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Discussion Starter · #1 · (Edited)
Greetings. I've lurked here for a while, learning my limitations and I'm ready to ask for some expert advice. I'm building a ’99 5.7 Vortec for a 66 GMC 1000 for decent street manners, some 1/8 mi bracket racing. I don’t expect it to see more than 5500 RPM. I want to build for torque, and I like compression. Truck has 3400# listed curb weight. TH350. Dana 44 axle w/3.54. 275/60-15 tires, 27.5” tall for street, 26/10.50-15 slicks for strip. ’77 C10 brake booster.

Block is OE roller, .030 over. I measured .029 deck w/old pistons & bearings. My piston choice is Summit 17350C-30 flat tops w/ 6cc valve reliefs, 1.561 compression height. I want to set deck at .015 and use .028 gasket, for .043 squish.. Calculated CR 10.6:1.
Heads were worked over for .550 lift, guides cut down, HP springs, screw-in studs, 3-angle grind. Keeping OE rockers. I measured 63cc chambers after surfacing.
Edelbrock 1905 650 cfm, Jegs 513002 manifold. I might add a 1" spacer.
1-5/8” long tube headers (Hooker Competition if I can find some),18” collector extension, crossover. 2.5” duals to bumper. Mufflers not yet chosen, but wife says it has to sound ******.

Looking at Comp XR276HR, 08-423-8 224/230, .502/.510, LS 110º. This looks like the longest duration that will operate a brake booster. Using Stealthformula’s overlap calculation shows 7º, but Comp says it has 12” hg @ 800 rpm. Their dyno graph shows a nice long torque curve, >400ftlb from 2700 to 4700. I like this. Wife should like the sound of the 7º.

Most of my choices were to get the most power per dollar. The pistons, manifold, keeping the OE rockers and roller lifters. Had the carb. I have to spend money on the cam, so I want the best streetable one that will make power for me.

Advice needed:
Is this a good choice of cam to get the most street torque and have some good manners?
Is 10.6 too much compression for this cam?
What fuel could I expect to run with this .043 squish? I’m willing to dial the timing back a bit M-F, then turn it up and fill the tank with 93 for Saturday night. Might less deck height (and more compression) prevent detonation?
What stall converter would be good with this build?
Are the “house brand” TC from the likes of Summit and Jeggs any good? How about B&M?

Lastly, what have I overlooked?

*edit: This HAS to be a budget build. I bought a rusty 77 C10 as a parts truck for my 66 GMC. 350 w/manifold, carb, headers, pretty valve covers, TH350, front crossmember, power steering, power brakes. A set of reworked iron heads, a set of roller rockers, and a 272 cam were in the deal. The VIN and emissions sticker said the lump of grease with the pretty dress parts was a 350.
My wife told me I spent waaay to much on it.
Me, thinking of Plan A (a $99 re-ring kit, a $129 trans kit, a $129 converter, and belts and hoses) said, "I can get this running in the 66 for $500".
I pulled the lump, scraped it off, and found a 305. I should have gone with Plan A.1: The $99 rering kit and a 200 shot of nitrous.
Nooooo. I went out and bought a 99 5.7 Vortec, with all the accessories. Serpentine drive, baby! Modern parts! Make REAL power!
Then on teardown I found water had been in the cylinders. 030 over. I found Vortec parts are >spendy<.
Like 3x what sbc parts cost. So, every time I think of a stroker kit, a Sniper, coated headers, I picture her arms folded and toe tapping.
Not because of the cost to build it, but because she told me to buy a crate motor.
 

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Greetings. I've lurked here for a while, learning my limitations and I'm ready to ask for some expert advice. I'm building a ’99 5.7 Vortec for a 66 GMC 1000 for decent street manners, some 1/8 mi bracket racing. I don’t expect it to see more than 5500 RPM. I want to build for torque, and I like compression. Truck has 3400# listed curb weight. TH350. Dana 44 axle w/3.54. 275/60-15 tires, 27.5” tall for street, 26/10.50-15 slicks for strip. ’77 C10 brake booster.

Block is OE roller, .030 over. I measured .029 deck w/old pistons & bearings. My piston choice is Summit 17350C-30 flat tops w/ 6cc valve reliefs, 1.561 compression height. I want to set deck at .015 and use .028 gasket, for .043 squish.. Calculated CR 10.6:1.
Heads were worked over for .550 lift, guides cut down, HP springs, screw-in studs, 3-angle grind. Keeping OE rockers. I measured 63cc chambers after surfacing.
Edelbrock 1905 650 cfm, Jegs 513002 manifold. I might add a 1" spacer.
1-5/8” long tube headers (Hooker Competition if I can find some),18” collector extension, crossover. 2.5” duals to bumper. Mufflers not yet chosen, but wife says it has to sound **.

Looking at Comp XR276HR, 08-423-8 224/230, .502/.510, LS 110º. This looks like the longest duration that will operate a brake booster. Using Stealthformula’s overlap calculation shows 7º, but Comp says it has 12” hg @ 800 rpm. Their dyno graph shows a nice long torque curve, >400ftlb from 2700 to 4700. I like this. Wife should like the sound of the 7º.

Most of my choices were to get the most power per dollar. The pistons, manifold, keeping the OE rockers and roller lifters. Had the carb. I have to spend money on the cam, so I want the best streetable one that will make power for me.

Advice needed:
Is this a good choice of cam to get the most street torque and have some good manners?
Is 10.6 too much compression for this cam?
What fuel could I expect to run with this .043 squish? I’m willing to dial the timing back a bit M-F, then turn it up and fill the tank with 93 for Saturday night. Might less deck height (and more compression) prevent detonation?
What stall converter would be good with this build?
Are the “house brand” TC from the likes of Summit and Jeggs any good? How about B&M?

Lastly, what have I overlooked?

Thanks!
I like what you have planned. The one thing that jumps out the most though is the compression. 10.6 is too much on iron heads. A full point lower would be perfect for your combo. The trouble with dialing back timing to keep it from pinging is power drops off faster than it would with less compression and the correct timing.
Your quench of .043 is great but even at 9.6 to 1 compression and that cam 91 octane gas would be preferred.
The 3.54 gears should be good on the street, but more gear would be better for the strip.
As far as a torque convertor goes, don't even mess around and get one custom built. It's money well spent and you'll never be happier. Most of the house brands are kind of a one size fits all thing and slippage could be a real problem.
Other than that, that cam should be fun with a nice lope at idle and decent street manners.
 

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If you really are looking for torque, a 3.75" stroke crank for a 383" stroker build is a much smarter move, especially at that weight and only 3.54 gear.
It's to the point now where you can buy the stroker rotating assembly kits at a cost nearly equal to the refurbishing cost of all the old parts.

That said, if you intend to stay stock stroke I don't see anything wrong with the plan, other than maybe a touch too much compression. I'd rather see about 10.2 if it isn't going to get a steady diet of premium grade pump gas.
If your willing to buy a good custom torque converter and not a shelf stock 'fitz-all stall', and step up one step (6°) on the cam duration then I wouldn't be afraid of the 10.6:1 plan.
Somethng like a 9-1/2" or 10" 35-3800 stall speed "tight" custom converter will act normal at partial throttles, then get up and boogie when you put the hammer down.
FTI, PTC, Transmission Specialties, Coan, Yank, Freakshow Performance could all handle the converter.

Stay away from B&M, TCI, Fairbanks, ACC/Alabama Boss Hog stay away.....B&M and TCI might still be able to do decent full competition converters, but the stuff you see in mail order parts dealers catalogs like Holeshot or Street fighter is just junk.

Last I knew The better Jegs brand converters, the XHD versions, were made by Transmission Specialties "white boxed" for Jeg's the last I knew, but that was a couple years back....pictures of the converter do still look the same though.
Pretty much comes down to the fact if you aren't spending $350+ on the converter, you aren't getting good stuff.

Don't know who might make the Summit converters.
 

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My comments in bold type:

Greetings. I've lurked here for a while, learning my limitations and I'm ready to ask for some expert advice. I'm building a ’99 5.7 Vortec for a 66 GMC 1000 for decent street manners, some 1/8 mi bracket racing. I don’t expect it to see more than 5500 RPM. I want to build for torque, and I like compression. Truck has 3400# listed curb weight. TH350. Dana 44 axle w/3.54. 275/60-15 tires, 27.5” tall for street, 26/10.50-15 slicks for strip. ’77 C10 brake booster.

Block is OE roller, .030 over. I measured .029 deck w/old pistons & bearings. My piston choice is Summit 17350C-30 flat tops w/ 6cc valve reliefs, 1.561 compression height. I want to set deck at .015 and use .028 gasket, for .043 squish.. Calculated CR 10.6:1.
10.6 is probably a bit much for an iron Vortec head.

Heads were worked over for .550 lift, guides cut down, HP springs, screw-in studs, 3-angle grind. Keeping OE rockers. Bad choice, the sliding shoe rocker drags across the valve stem with a lot of force when you get into high lifts which results in a lot of guide wear, especially when the guide is shortened for high lift. Add to the problem is the ball fulcrum gets really hot with high lift and serious valve springs. A full roller rocker is a more durable, less wearing solution all the way around. My recommendation is on a 7/16ths stud this adds a lot of needed stiffness that allows you to rev out to tge cam’s and valve spring‘s abilities otherwise the wavering 3/8ths stud stops RPM growth before you hit these other limiting factors by a lot of RPM.

I measured 63cc chambers after surfacing. I wouldn’t have spent a dime on the Vortec head’s, even the least costly aluminum imports would have been the better all around choice for detonation tolerance and power output.
Edelbrock 1905 650 cfm, Not a good choice the cam you’re looking at will demand quite a bit of tuning and 4 corner idle none of which are present on the otherwise very fine Edelbrock. Jegs 513002 manifold. Nothing combines the virtues of good street manners and high performance like the Edelbrock Performer RPM. I might add a 1" spacer.
1-5/8” long tube headers (Hooker Competition if I can find some) To small for the cam look for 1-3/4 , 18” collector extension, crossover. 2.5” duals to bumper. Mufflers not yet chosen, but wife says it has to sound **.

Looking at Comp XR276HR, 08-423-8 224/230, .502/.510, LS 110º. This looks like the longest duration that will operate a brake booster. Wi’ll require a high stall converter if running an automatic Comp recommends a 2000+ stall my experience is this will want something more like 2900-3200. Using Stealthformula’s overlap calculation shows 7º, but Comp says it has 12” hg @ 800 rpm. Their dyno graph shows a nice long torque curve, >400ftlb from 2700 to 4700. I like this. Wife should like the sound of the 7º.

Most of my choices were to get the most power per dollar. The pistons, manifold, keeping the OE rockers and roller lifters. Had the carb. I have to spend money on the cam, so I want the best streetable one that will make power for me. The XR264 is more streetable!

Advice needed:
Is this a good choice of cam to get the most street torque and have some good manners?
Is 10.6 too much compression for this cam? Within some kind of reason reducing timing lead to get under the detonation limit costs more power than backing down the compression ratio.
What fuel could I expect to run with this .043 squish? I’m willing to dial the timing back a bit M-F, then turn it up and fill the tank with 93 for Saturday night. Might less deck height (and more compression) prevent detonation? Detonation is funny stuff but aluminum head’s are way more tolerant than Iron maybe a better word is suppressive.
What stall converter would be good with this build? As I said earlier 2800 to 3200.
Are the “house brand” TC from the likes of Summit and Jeggs any good? How about For just playing around the edges of performance these are probably good enough, hopefully you have budgeted a tranny rebuild on the front end putting a frisky power plant on a tired automatic nets a major rebuild sooner than later.

Lastly, what have I overlooked? Rods, the GM powder forged on the Gen I and IIs are not trustworthy, neither are hypereutectic pistons, when these things give up all your investment is in a pile of junk. It’s one thing to build a good performing street engine, it’s something else to take it racing. The excitement of competition leads one to go deeper that they built for, it’s human nature at its finest.

Thanks!
A 383 would be a better build with a lot more torque on less cam. Since you need better rods and pistons, it’s just the cost of a crank, in a case like yours a SCAT cast steel crank goes a long way for not a lot of money.

Bogie
 

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I had that cam in pretty much the same combo, only my 99 L31 only got rings and bearings. The block was decked, but I never calculated my final compression. But if Eric says it will work, you will be fine.
Mine ended up pushing a 4020 pound Squarebody 13.5s in the quarter. It ran very similar to the 406 I have right now. Good torque, good good torque with that cam.
And when I purchased a nice converter, seat of the pants feel was amazing. Along with a .4 second improvement in the 1/4. Both converters behaved the same, just the cheap one soaked up a lot of power. So much, I had to start using drag radials after because of traction problems...
Your weight has been mentioned before, but if you really are only 3600 that thing will move out pretty good.
I used stock rockers, and pushrods on mine, with an RPM Intake. I had a 670 Street Avenger, but I would recommend a 750 Holley or equivalent.
Power brakes worked fine. It was a really good running motor, and would have done good in a lighter car!
 

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10.6:1 will work with premium and the very efficient vortec chambers, but you might have to get creative with timing curves. It's a little excessive, but not way off. I ran the next size smaller cam on a similar combo at 9.5:1 on 87 octane and it was just fine. Your problem is that the easy way to drop compression a bit is to do a thicker head gasket, but then your quench will suck and it may not do any good for detonation tolerance.

Only other thing I can see that I don't personally like (just opinion) is the 1905 Edelbrock. It's the old-schooliest, low-techiest, thing you can do. It's a 60-year old Carter design that hasn't really been changed much. It's a chunk of aluminum that mixes fuel and air, but not well. I would much rather see a good Qjet or Holley-type carb on it. 600 cfm isn't really too small, but you will get a couple more ponies from a 750 and not really give up much down low.
 

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Discussion Starter · #8 ·
I had that cam in pretty much the same combo, only my 99 L31 only got rings and bearings. The block was decked, but I never calculated my final compression. But if Eric says it will work, you will be fine.
Mine ended up pushing a 4020 pound Squarebody 13.5s in the quarter. It ran very similar to the 406 I have right now. Good torque, good good torque with that cam.
And when I purchased a nice converter, seat of the pants feel was amazing. Along with a .4 second improvement in the 1/4. Both converters behaved the same, just the cheap one soaked up a lot of power. So much, I had to start using drag radials after because of traction problems...
Your weight has been mentioned before, but if you really are only 3600 that thing will move out pretty good.
I used stock rockers, and pushrods on mine, with an RPM Intake. I had a 670 Street Avenger, but I would recommend a 750 Holley or equivalent.
Power brakes worked fine. It was a really good running motor, and would have done good in a lighter car!
Thanks, that's reassuring.
 

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Discussion Starter · #9 ·
10.6:1 will work with premium and the very efficient vortec chambers, but you might have to get creative with timing curves. It's a little excessive, but not way off. I ran the next size smaller cam on a similar combo at 9.5:1 on 87 octane and it was just fine. Your problem is that the easy way to drop compression a bit is to do a thicker head gasket, but then your quench will suck and it may not do any good for detonation tolerance.

Only other thing I can see that I don't personally like (just opinion) is the 1905 Edelbrock. It's the old-schooliest, low-techiest, thing you can do. It's a 60-year old Carter design that hasn't really been changed much. It's a chunk of aluminum that mixes fuel and air, but not well. I would much rather see a good Qjet or Holley-type carb on it. 600 cfm isn't really too small, but you will get a couple more ponies from a 750 and not really give up much down low.
I'm "saving money" with the carb I already have...unless I see a clean used Holley.
What sort of timing curve creativity do you suggest?
 

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Discussion Starter · #11 ·
If you really are looking for torque, a 3.75" stroke crank for a 383" stroker build is a much smarter move, especially at that weight and only 3.54 gear.
It's to the point now where you can buy the stroker rotating assembly kits at a cost nearly equal to the refurbishing cost of all the old parts.

That said, if you intend to stay stock stroke I don't see anything wrong with the plan, other than maybe a touch too much compression. I'd rather see about 10.2 if it isn't going to get a steady diet of premium grade pump gas.
If your willing to buy a good custom torque converter and not a shelf stock 'fitz-all stall', and step up one step (6°) on the cam duration then I wouldn't be afraid of the 10.6:1 plan.
Somethng like a 9-1/2" or 10" 35-3800 stall speed "tight" custom converter will act normal at partial throttles, then get up and boogie when you put the hammer down.
FTI, PTC, Transmission Specialties, Coan, Yank, Freakshow Performance could all handle the converter.

Stay away from B&M, TCI, Fairbanks, ACC/Alabama Boss Hog stay away.....B&M and TCI might still be able to do decent full competition converters, but the stuff you see in mail order parts dealers catalogs like Holeshot or Street fighter is just junk.

Last I knew The better Jegs brand converters, the XHD versions, were made by Transmission Specialties "white boxed" for Jeg's the last I knew, but that was a couple years back....pictures of the converter do still look the same though.
Pretty much comes down to the fact if you aren't spending $350+ on the converter, you aren't getting good stuff.

Don't know who might make the Summit converters.
Thanks for the great advice.
I'm gonna get off my wallet for a good converter. Your description of the results is exactly what I want.

The XR282 is too radical for me. If I understand the physics, XR282 has less dynamic compression than XR276, so the engine can stand more static compression. The hair-puller is the tradeoff between parts cost, fuel cost, and power.

The KB193-30 D-cups get me 9.74:1 with .040 squish.
The flat-tops are three bills less than the KB D-cups. Haven't found any other D that keeps the 1.56 compression height. I can get 10.2:1 with flat tops and .048 squish.
Would it be wrong to find a "rebuilder" piston with less compression height, a D-cup and cut the deck a bunch?
Assuming the XR276, 32º timing, as close to .040 squish as possible,
What octane for 9.7:1?
What octane for 10.2:1?
Will I gain any significant power going from 9.7 to 10.2?

I appreciate your insight.
 

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I'm "saving money" with the carb I already have...unless I see a clean used Holley.
What sort of timing curve creativity do you suggest?
Gotcha. Then go for it with the 1905. Alternatively, $60 should get you a junkyard Qjet and a rebuild kit if you're feeling adventurous.

Timing curve will probably be ok if you just retard it a bit. Use weights to give you a total of 22 or so worth of mechanical and set initial around 10 ish? Springs I would choose to have full mechanical by 3200-3500 rpm. Use an adjustable vac canister to tailor detonation out of part throttle and cruise. My rule is, (however the directions tell you to adjust... usually something like 1/2 turn per 2 degrees or something) add vacuum until you get detonation. Back it off until you don't hear it anymore on the hottest day, then go two more degrees since some detonation can happen without you hearing it.

You need enough initial for idle, but it is not an overly important number. 34 total is about the sweet spot for most Vortecs, but you might need to keep it to 32 or so. My actual process would be to stab it in and set initial to get your 32 total. Advance it a bit until you get detonation then back it off 2 degrees but any more than 34 total mechanical is excessive. Then, if you don't have enough initial, change your weights for less mechanical and bump up initial.

I think you can still buy test knock sensors that thread into the block somewhere and just lead to a light. It can be very helpful when tuning an ignition curve on the edge like that.
 

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I'm fine with the 10.2:1, flat tops, and .048" squish, I would roll with that no problem, 89 octane midgrade until it gets really hot dead summer may demand 91 super.
You don't want to deck the block any more than you have to, everything you take off is a % of strength lost. Deck cut just enough to get flat and square with the crank.
Cutting the deck a bunch to fit a short piston messes with deck strength, intake fit, pushrod length, stripping head bolt holes. Not a good idea.

D.S.S. Pistons has a 2 relief flat top, 4cc relief, forged for the same price as those KB Hypers.
$349.
8700-4000 350 SBC E Series -4cc Flat Top Piston Set. 4.000 bore (dssracing.com)

Summit Racing has a coated skirt 4 relief flat top forged piston if you really need to pinch the budget.
$299
CHEVROLET Summit Racing SUM-17360FC-30 Summit Racing® Coated Forged Pistons | Summit Racing
383 forged piston
$319
CHEVROLET Summit Racing SUM-17365FC-60 Summit Racing® Coated Forged Pistons | Summit Racing

The $150 cost difference would be the best insurance you ever bought. I've seen enough exploded hypers.
 

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Gotcha. Then go for it with the 1905. Alternatively, $60 should get you a junkyard Qjet and a rebuild kit if you're feeling adventurous.

Timing curve will probably be ok if you just retard it a bit. Use weights to give you a total of 22 or so worth of mechanical and set initial around 10 ish? Springs I would choose to have full mechanical by 3200-3500 rpm. Use an adjustable vac canister to tailor detonation out of part throttle and cruise. My rule is, (however the directions tell you to adjust... usually something like 1/2 turn per 2 degrees or something) add vacuum until you get detonation. Back it off until you don't hear it anymore on the hottest day, then go two more degrees since some detonation can happen without you hearing it.

You need enough initial for idle, but it is not an overly important number. 34 total is about the sweet spot for most Vortecs, but you might need to keep it to 32 or so. My actual process would be to stab it in and set initial to get your 32 total. Advance it a bit until you get detonation then back it off 2 degrees but any more than 34 total mechanical is excessive. Then, if you don't have enough initial, change your weights for less mechanical and bump up initial.

I think you can still buy test knock sensors that thread into the block somewhere and just lead to a light. It can be very helpful when tuning an ignition curve on the edge like that.
I see that GM says the vacuum should NOT be hooked up for the 350/357 vortec crate engine. Am wondering why this is.
 

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Discussion Starter · #15 ·
Gotcha. Then go for it with the 1905. Alternatively, $60 should get you a junkyard Qjet and a rebuild kit if you're feeling adventurous.

Timing curve will probably be ok if you just retard it a bit. Use weights to give you a total of 22 or so worth of mechanical and set initial around 10 ish? Springs I would choose to have full mechanical by 3200-3500 rpm. Use an adjustable vac canister to tailor detonation out of part throttle and cruise. My rule is, (however the directions tell you to adjust... usually something like 1/2 turn per 2 degrees or something) add vacuum until you get detonation. Back it off until you don't hear it anymore on the hottest day, then go two more degrees since some detonation can happen without you hearing it.

You need enough initial for idle, but it is not an overly important number. 34 total is about the sweet spot for most Vortecs, but you might need to keep it to 32 or so. My actual process would be to stab it in and set initial to get your 32 total. Advance it a bit until you get detonation then back it off 2 degrees but any more than 34 total mechanical is excessive. Then, if you don't have enough initial, change your weights for less mechanical and bump up initial.

I think you can still buy test knock sensors that thread into the block somewhere and just lead to a light. It can be very helpful when tuning an ignition curve on the edge like that.
Understood. Made notes, added the vac pot and curve kit to the parts list. Thank you.
 

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I see that GM says the vacuum should NOT be hooked up for the 350/357 vortec crate engine. Am wondering why this is.
This cam times a little longer on duration but uses less lift and a lot less LSA than say the LT4HOT cam. The 357/350 cam is 215/223 at .050 with .473/.473 lift with a 1.5 rocker using a 108 degree LSA. The HOT cam is 210/228 at .050 with .492/.492 lift with a 1.5 rocker using a 112 degree LSA. So the cam used in the 357/350 will have low idle vacuum probably 12 to 10 inches rendering vacuum advance outside a useful operating range. Idle with this cam will be rough sounding along the lines of Thumper cams. For the street this would not be my desire unless I was 60 years younger and had a manual transmission in the vehicle.

Bogie
 

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Discussion Starter · #17 ·
I'm fine with the 10.2:1, flat tops, and .048" squish, I would roll with that no problem, 89 octane midgrade until it gets really hot dead summer may demand 91 super.
You don't want to deck the block any more than you have to, everything you take off is a % of strength lost. Deck cut just enough to get flat and square with the crank.
Cutting the deck a bunch to fit a short piston messes with deck strength, intake fit, pushrod length, stripping head bolt holes. Not a good idea.

D.S.S. Pistons has a 2 relief flat top, 4cc relief, forged for the same price as those KB Hypers.
$349.
8700-4000 350 SBC E Series -4cc Flat Top Piston Set. 4.000 bore (dssracing.com)

Summit Racing has a coated skirt 4 relief flat top forged piston if you really need to pinch the budget.
$299
CHEVROLET Summit Racing SUM-17360FC-30 Summit Racing® Coated Forged Pistons | Summit Racing
383 forged piston
$319
CHEVROLET Summit Racing SUM-17365FC-60 Summit Racing® Coated Forged Pistons | Summit Racing

The $150 cost difference would be the best insurance you ever bought. I've seen enough exploded hypers.
Summit snuck in some rebuilder pistons with the 17360 - 1.550 height instead of 1.560.
I found $339 Speed-Pro L2256F30 forged flattop, 6.1cc, and 1.563 compression height... puts me at a magical .041 squish.
You are on the money about "hot dead summer". I got really stupid on that kind of day and broke a cast piston in my old 429. Really stupid. The insurance of which you speak is wise.
Thanks
 

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What about the Skip White rotating assemblies in 383 config with the high compression height forged pistons. Should be able to match up a dished piston to get nice lower CR and good squish with minimal decking of block. Plus Scat crank and rods. Dont know about vortec heads on a 383 though.

Sent from my moto g power using Tapatalk
 

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I dont like that combo much at all. The vortec heads run into stall of airflow when valve lift gets that high. If you get someone like Chad spieir to do your heads then the high lift cam can work but you are way better off getting heads that flow better in aluminum,,,especially at 10 1/2:1 cr.
Run a .440 lift cam that will pull 6k. Use a 750 cfm carb on a dual plane. with vortec heads 9 3/4:1 cr. 1 5/8 long tube headers. I like 3.54 gears. Get an after market coil if you use GM hei.
 

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I dont like that combo much at all. The vortec heads run into stall of airflow when valve lift gets that high. If you get someone like Chad spieir to do your heads then the high lift cam can work but you are way better off getting heads that flow better in aluminum,,,especially at 10 1/2:1 cr.
Run a .440 lift cam that will pull 6k. Use a 750 cfm carb on a dual plane. with vortec heads 9 3/4:1 cr. 1 5/8 long tube headers. I like 3.54 gears. Get an after market coil if you use GM hei.
Why only .440" lift?

The OP has already outfitted the heads to handle .550" lift.
 
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