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Old 06-24-2010, 10:43 PM
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Is 400HP too high for build??

I am building a 350 for my 1978 Camaro, I will be using
1972 Block
441 Heads, shaved .030, maybe bigger valves?
Edelbrock Performer intake
Standard Bore? Would I need like 0.030 over for 400 HP?
Holley 750 duel line
Hooker Headers
True duel flow master 40s
Summit distributor, 50,000v coil adjustable advance, low resistance bushing.

Really would like to hit 400HP, but after all torque is where its at and I would like as much as possible. Would this be a good build for that? If I bore it .030 over I will use flat tops with 4 valve reliefs. How much would bigger valves and the bore and pistons add? Would Roller tipped rockers help?

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  #2 (permalink)  
Old 06-25-2010, 01:18 AM
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441 heads have 155cc intake runners, 76cc chambers and the following flow numbers....

0.100 55/45
0.200 110/83
0.300 160/118
0.400 194/133
0.500 201/146
0.600 203/148

They do not appear to me to be a good foundation for a 400 hp 350 motor.

Cutting them 0.030" should yield about a 71cc chamber. Using flat-top, 4-relief pistons with a 1.560" compression height, 0.025" down in the hole and a 0.040" gasket will yield a 8.98:1 static compression ratio. A cam like the following Crane flat tappet hydraulic will match up with the SCR and give you a nice little 350 for everyday driving.
http://www.summitracing.com/parts/CRN-113901/

You want 400 hp? Pony up for some cylinder heads that will support 400 hp.
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Old 06-25-2010, 01:19 AM
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Quote:
Originally Posted by lizardking7750
I am building a 350 for my 1978 Camaro, I will be using
1972 Block
441 Heads, shaved .030, maybe bigger valves?
Edelbrock Performer intake
Standard Bore? Would I need like 0.030 over for 400 HP?
Holley 750 duel line
Hooker Headers
True duel flow master 40s
Summit distributor, 50,000v coil adjustable advance, low resistance bushing.

Really would like to hit 400HP, but after all torque is where its at and I would like as much as possible. Would this be a good build for that? If I bore it .030 over I will use flat tops with 4 valve reliefs. How much would bigger valves and the bore and pistons add? Would Roller tipped rockers help?
Get you a set of vortec heads with matching intake(carburated) and a comp xe262 cam along with the rest of your goodies and you'll be well over 400hp and would be very streetable
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Old 06-25-2010, 03:20 AM
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Here's a reasonable formula....
Bore the block 0.030", use these or other 12cc pistons w/5.7 rods....
http://www.kb-silvolite.com/test/kb...etails&P_id=155
Makes 9.6:1 static compression ratio. Cut block decks to zero and use a 0.040" head gasket.
Use XE274H Comp cam installed at zero with Comp 981 valve springs/ 750-16 retainers/ 630-16 keepers and stock 1.5 rail rockers.... 1.250" springs should be OK because the cam is a moderate grind, hydraulic flat tappet.....Narrow the O.D. of the guides to less than the I.D. of the damper spring and cut for PC-type positive seals...Cut top of guide for 0.550" play from bottom of retainer to top of guide seal. Pin the pressed-in rocker studs with this kit....
http://www.summitracing.com/parts/M...15&autoview=sku
Performance Distributors 12720 HEI, custom curved...
http://www.performancedistributors.com/gmssdui.htm
Cam card is here....
http://www.compcams.com/Cam_Specs/C...px?csid=87&sb=0
Edelbrock RPM Vortec intake mounting a 750 vacuum secondaries carb of your choice. Edelbrock, Rochester 5 psi max at the inlet, Holley 6 psi max at the inlet.
Performer RPM Vortec #7116*
Performer RPM Vortec w/ EnduraShine finish #71164*
Polished Performer RPM Vortec #71161*
Look for a used manifold on craigslist to save a few sheckels.
Long-tube 1 5/8" headers with X or H pipe right after the collectors, 2 1/2"/2 3/4" pipes to the rear through mufflers of your choice.
Use 2500 stall converter, shorter rear gears.
I factored the published head flow times 0.95 for this DynoSim....
RPM HP TQ
2000 138 364
2500 176 369
3000 224 392
3500 281 421
4000 331 435
4500 370 432
5000 402 422
5500 405 386
6000 375 328
Peak dynamic compression ratio 8.16:1 on KB's calculator.
Peak volumetric efficiency 97.2% @5000
Peak BMEP 184.5 @4000

In this build, I would be interested in spending the least amount of money. In that vein, I would use stock rail rockers. Lift is under a half inch, so I would think the RR would be ok. Since I'm not sure that all locks locate the valve tip the same, relative to the top of the retainer, I would welcome input from others about using a (-0.050") lock (that's what I used above.) to insure the valve tip sticks up far enough above the retainer so that the retainer top surface doesn't get loaded by the side rails of the rail rockers. Break in the cam on the stock L31 springs, then change to the comp springs after a couple hundred miles. Use an extreme pressure oil additive at break in and at subsequent oil changes. One bottle of this Crower product added to the engine oil on break-in and at each oil change will provide your flat tappet cam with the protection it needs, while operating on any available off-the-shelf motor oil.
http://www.summitracing.com/parts/CRO-86092/
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Old 06-25-2010, 04:38 AM
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Quote:
Originally Posted by techinspector1
Here's a reasonable formula....
Bore the block 0.030", use these or other 12cc pistons w/5.7 rods....
http://www.kb-silvolite.com/test/kb...etails&P_id=155
Makes 9.6:1 static compression ratio. Cut block decks to zero and use a 0.040" head gasket.
Use XE274H Comp cam installed at zero with Comp 981 valve springs/ 750-16 retainers/ 630-16 keepers and stock 1.5 rail rockers.... 1.250" springs should be OK because the cam is a moderate grind, hydraulic flat tappet.....Narrow the O.D. of the guides to less than the I.D. of the damper spring and cut for PC-type positive seals...Cut top of guide for 0.550" play from bottom of retainer to top of guide seal. Pin the pressed-in rocker studs with this kit....
http://www.summitracing.com/parts/M...15&autoview=sku
Performance Distributors 12720 HEI, custom curved...
http://www.performancedistributors.com/gmssdui.htm
Cam card is here....
http://www.compcams.com/Cam_Specs/C...px?csid=87&sb=0
Edelbrock RPM Vortec intake mounting a 750 vacuum secondaries carb of your choice. Edelbrock, Rochester 5 psi max at the inlet, Holley 6 psi max at the inlet.
Performer RPM Vortec #7116*
Performer RPM Vortec w/ EnduraShine finish #71164*
Polished Performer RPM Vortec #71161*
Look for a used manifold on craigslist to save a few sheckels.
Long-tube 1 5/8" headers with X or H pipe right after the collectors, 2 1/2"/2 3/4" pipes to the rear through mufflers of your choice.
Use 2500 stall converter, shorter rear gears.
I factored the published head flow times 0.95 for this DynoSim....
RPM HP TQ
2000 138 364
2500 176 369
3000 224 392
3500 281 421
4000 331 435
4500 370 432
5000 402 422
5500 405 386
6000 375 328
Peak dynamic compression ratio 8.16:1 on KB's calculator.
Peak volumetric efficiency 97.2% @5000
Peak BMEP 184.5 @4000

In this build, I would be interested in spending the least amount of money. In that vein, I would use stock rail rockers. Lift is under a half inch, so I would think the RR would be ok. Since I'm not sure that all locks locate the valve tip the same, relative to the top of the retainer, I would welcome input from others about using a (-0.050") lock (that's what I used above.) to insure the valve tip sticks up far enough above the retainer so that the retainer top surface doesn't get loaded by the side rails of the rail rockers. Break in the cam on the stock L31 springs, then change to the comp springs after a couple hundred miles. Use an extreme pressure oil additive at break in and at subsequent oil changes. One bottle of this Crower product added to the engine oil on break-in and at each oil change will provide your flat tappet cam with the protection it needs, while operating on any available off-the-shelf motor oil.
http://www.summitracing.com/parts/CRO-86092/
I vouch for cam head and intake swap
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Old 06-25-2010, 04:52 AM
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I agree with most everything above with the exception of boring the motor. Just bore it enough to take out the defects in the cylinder wall. Might even be .010 or just a hone, you never know. Leave yourself some meat for next time, boring is expensive and it really adds no power.

K
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Old 06-25-2010, 05:09 AM
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Quote:
Originally Posted by killerformula
I agree with most everything above with the exception of boring the motor. Just bore it enough to take out the defects in the cylinder wall. Might even be .010 or just a hone, you never know. Leave yourself some meat for next time, boring is expensive and it really adds no power.

K
TRUE
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Old 06-25-2010, 05:50 AM
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Quote:
Originally Posted by lizardking7750
I am building a 350 for my 1978 Camaro, I will be using
1972 Block
441 Heads, shaved .030, maybe bigger valves?
Edelbrock Performer intake
Standard Bore? Would I need like 0.030 over for 400 HP?
Holley 750 duel line
Hooker Headers
True duel flow master 40s
Summit distributor, 50,000v coil adjustable advance, low resistance bushing.

Really would like to hit 400HP, but after all torque is where its at and I would like as much as possible. Would this be a good build for that? If I bore it .030 over I will use flat tops with 4 valve reliefs. How much would bigger valves and the bore and pistons add? Would Roller tipped rockers help?
Yeah, this combo won't get you 400hp. I've run an engine almost exactly to those specs (with .030-over flat-tops), except the 750-holley (ran a 600, 0-1850). Ran a Comp Cams 260H. Good torque, not real big on the HP. I liked the way it idled, pulled good from idle to about...4000rpm maybe? Good for everyday driving.
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Old 06-25-2010, 06:33 AM
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1.21 giga-watts???!!!!
 
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How many articles and stories of 400 + HP using Vortec heads are out there for anybody to copy and use as a plan?

Bigger valves? For the street? Why?
Holley 750? Why? You haven't even picked a cam yet.

Vortec heads (pocket ported), Comp XE 268 or 262, headers, carb of your choice in 650 or 750 range, 1.6 ratio rockers on intakes and exhaust. Easy 400 hp and 400 tq.

This topic has been beat to death. Did you use the forum search and punch in "400 HP small block"? Probably not. This is not a rant directed at you specifically. It's to all the guys out there that refuse to use one of the coolest features of this site...Forum Search. Of course, if more people used it, the number of new posts would go down by about 90%
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Old 06-25-2010, 10:26 AM
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The cam thats in the motor is the Summit brand .488 lift. I bought the motor with it in it. Boring costing $8 per cylinder at my local machine shop. I guess I will have to find some vortecs, everything seems to point to them.
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Old 06-25-2010, 12:47 PM
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1.21 giga-watts???!!!!
 
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I think you will be happy with them. When I have the dough, I am picking up some Bowtie 180 heads from GM Performance Parts. Hoping I can find a collector who will want my 041 heads.
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Old 06-25-2010, 02:25 PM
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How to get 400hp using 441 heads.....

Its all about airflow. To get the port flow up to make 400hp with these heads requires a full port job. You need to get the flow up 230cfm+ ( like a vortec head or a Edelbrock rpm head.)
Full porting is not the same as a "pocket port job"

10:1 cr (small dome piston with 441 76cc heads)
performer rpm manifold +750cfm carb
Long tube headers
hyd or solid cam with 234 to 248 @.050" duration .500" ish lift.

The resulting engine will want a 3000+ stall converter and 3.73-4.56 gears in your typical street machine.
Ya its easier to just bolt on vortecs.
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Old 06-25-2010, 03:26 PM
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Quote:
Originally Posted by killerformula
Might even be .010 or just a hone
The problem w/that is there needs to be about 0.003" left to hone the cylinder w/plates, the bore is going to be worn some amount, so you would need to set up to bore something on the order of a ~0.003" to 0.005" material removal.

Then you need to find 0.010" over pistons.

I think you'll have a lot better luck shooting for at least a 0.020" over, and a LOT better piston selection at 0.030".
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Old 06-26-2010, 07:38 PM
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A guy wants to trade me his 370 double humps for my 441s, this is a good deal right? Are they good performing heads?
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Old 06-26-2010, 08:24 PM
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Never heard of 370's, looked for the number, couldn't find it. You should double check that number.
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