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72 Nova, 65 Rambler, 37 Chevy
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Discussion Starter · #1 ·
I have a 350 and it is quite sluggish below 3000 - cant spin the tires (882 heads, 8.5 CR, 224* .465" 114LSA cam, 2000 stall and 3.08 rear gear) Im looking for a way to get alittle bit more bottem end out of it. It pulls real nice past 2800ish.

I was thinking advancing the cam (or is it retarding) from the timing chain. (My crank gear has 3 keyways, staight up and 4* either way) would this help bring the power range down at all?

Also I was considering using a .020 gasket to bump the compression a bit, and porting the 882s a bit.

I think a main problem here is the heads. Would changing to a set of 461's improve much? (62cc chambers giving atleast 9.5:1 with the thin gasket).

Would any of this help? Anything else inexpensive I can do without changing to a smaller cam. (oh yea the motor is apart now, so I might as well fix it now)
 

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ASE Certified Master Machinist
1967 Chevrolet Biscayne 10-71 blown 433 Big Block Chevy, T400 & 12 bolt 3.73 rearend
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The best thing to do is the one you don't want to do...swap in a smaller cam. You don't have enough compression for that cam. If you increase the compression ratio, it will help. I would use and recommend using Vortec heads instead of the 461's. Much better flow and more efficient combustion chambers.

Barry
 

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Errrrrrrrrr, lets come back to earth and think about those rear end gears. Describe the vehicle this thing is going in. A 8.5 compression engine can easily be competitive, just look at the super stock/stock drag racing classes. Going to high 3. to low 4. rear gears will wake up nearly any engine. The engine is not the only thing in the combination. Look at the whole picture not just part of it.
 

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72 Nova, 65 Rambler, 37 Chevy
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Discussion Starter · #5 ·
QuenchPiston said:
Errrrrrrrrr, lets come back to earth and think about those rear end gears. Describe the vehicle this thing is going in. A 8.5 compression engine can easily be competitive, just look at the super stock/stock drag racing classes. Going to high 3. to low 4. rear gears will wake up nearly any engine. The engine is not the only thing in the combination. Look at the whole picture not just part of it.
Its a bare bones 72 nova, th350 trans, like i said ealier with the 1800-2200 stall with peg leg 3.08. The converter stalled at about 1900 when I had it running.

I have a posi now and I figure Ill swap 3.73s(or higher?) in when I do the posi.
 

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topfuel said:
The best thing to do is the one you don't want to do...swap in a smaller cam. You don't have enough compression for that cam.
Barry
I'll second that. I had the exact same combo in a 350 and it was a slug off the line. Switched to a smaller cam (210/214 @ .050, 267 adv., w/.444 lift and 112 lsa) and it ran stronger all the way around.
Not to say that a stall and gears won't help (they will) but a fatter torque range is also preferable.
 

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Had this one in a low compression 360 w/mild ported 2.02 1.60, single plane engine in a A body. Stock stall converter and 3.55 hears and had no problem breaking tires loose but it did come alive after 2000rpm.

Duration at 050 inch Lift: 241 int./241 exh.
Advertised Duration: 284 int./284 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.484 int./0.484 exh. lift
Lobe Separation (degrees): 108
 

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Analog man in a digital world.
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Warrant said:
I have a 350 and it is quite sluggish below 3000 - cant spin the tires (882 heads, 8.5 CR, 224* .465" 114LSA cam, 2000 stall and 3.08 rear gear) Im looking for a way to get alittle bit more bottem end out of it. It pulls real nice past 2800ish.
WOW! DEJA VU all over again!!! I built almost the exact same motor back in the early 80's for a '79 Camaro with a supposedly 2500 stall converter ( 2500 my BUTT! :mad: ), TH350 and 3.42 posi. Until you hit 3 Grand it was completely gutless, couldn't even brake loose a bald set of 215-70 X 15's!. But once it hit 3,000 you better be hanging on because your were going for a ride! :eek: But by then the other guy was L-O-N-G gone..............

Get your compression up to around 9.5 to 1 or so and try get a true 2500 stall converter and at least 3.42 gears, preferably 3.73's. I assume you are running a dual plane intake, if not get a Performer RPM. If that gets you closer to the mark then you can play with cam timing. If isn't better then it's cam time, a tighter LSA would help. If you are "married" to the 3.08 gears and 2,000 converter then it is definitely time for a smaller cam.

QuenchPiston said:
Had this one in a low compression 360 w/mild ported 2.02 1.60, single plane engine in a A body. Stock stall converter and 3.55 hears and had no problem breaking tires loose but it did come alive after 2000rpm.

Duration at 050 inch Lift: 241 int./241 exh.
Advertised Duration: 284 int./284 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.484 int./0.484 exh. lift
Lobe Separation (degrees): 108
Lobe Separation (degrees): 108

That had a lot to do with it I bet............
 

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72 Nova, 65 Rambler, 37 Chevy
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341 Posts
Discussion Starter · #10 ·
runn141 said:
the motor is fine, if u want to continue to use the 3.08 gear put a stock torque converter in possibly a 13 inch from a turbo 400. it may sound silly but ive done it and it works
QuenchPiston said:
Had this one in a low compression 360 w/mild ported 2.02 1.60, single plane engine in a A body. Stock stall converter and 3.55 hears and had no problem breaking tires loose but it did come alive after 2000rpm.

Duration at 050 inch Lift: 241 int./241 exh.
Advertised Duration: 284 int./284 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.484 int./0.484 exh. lift
Lobe Separation (degrees): 108
Hmmm well w.t.f.
 

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72 Nova, 65 Rambler, 37 Chevy
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Discussion Starter · #11 ·
Hippie said:
I assume you are running a dual plane intake, if not get a Performer RPM. If that gets you closer to the mark then you can play with cam timing. If isn't better then it's cam time. If you are "married" to the 3.08 gears and 2,000 converter then it is definitely time for a smaller cam.
I have a weiand action + 8004 with stock quadrajet. Definitly not married to that converter and gear.

Can the 882s be milled at all? (thin casting) also does this change valve train geometry? will i need longer pushrods?
 

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Warrant said:
I have a weiand action + 8004 with stock quadrajet. Definitly not married to that converter and gear.

Can the 882s be milled at all? (thin casting) also does this change valve train geometry? will i need longer pushrods?
882s are one of the best to be milled,youll need to index the pushrods also. i see your using a q jet if it works fine id change that converter first and see what happens before you change a gear your cam, intake and compression ratio is matched well.
 

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Warrant said:
How much should I mill off? whats the going rate for a shop to do that? Can they be milled with the heads assembled (valves n springs in)?
i think if the heads have never been touched and their 76cc having.030 milled off will bring the down to 70cc. i dont know the price they have changed over the last 3 years around here as far as being assembled or not thats up to the shop if they want them unassembled itll be cheaper if u do it of course. most shops dont like to mill more than .050 though
 

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Analog man in a digital world.
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Warrant said:
I have a weiand action + 8004 with stock quadrajet. Definitly not married to that converter and gear.

Can the 882s be milled at all? (thin casting) also does this change valve train geometry? will i need longer pushrods?

Good manifold and carb for low end. Never tried milling the 882's personally, been 20 years or so since I owned any. You should be able to skim a little off them though and run a steel shim head gasket, it can only help. I'd check your local machine shops that do work for the street stock / bomber class dirt track racers. They should have lots of experience with 882 heads and how far you can safely mill them. What are you running for pistons and how far below the deck are they at TDC? The little bit you mill your heads and the thinner gasket shouldn't affect your valvetrain enough to need different pushrods. Cam change and thinner head gasket would be a lot easier and cheaper...............especially if you have it apart already.

My old room mate had an 8.5 to 1 350 very similar to yours back in the 80's, same heads, intake and carb but if I remember right with a Speed Pro cam just like the Summit 1103 cam, 214/224 @ .050" on 112 LSA . It was in a '74 El Camino that orignally had a 454 and it still had the stock big block converter, a TH400 and 2.73 posi. It would roast the tires at will and lay posi for 2 blocks on a hot day ( Much to the dismay of our land lady who lived next door! :spank: )
 

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Hippie said:
WOW! DEJA VU all over again!!! I built almost the exact same motor back in the early 80's for a '79 Camaro with a supposedly 2500 stall converter ( 2500 my BUTT! :mad: ), TH350 and 3.42 posi. Until you hit 3 Grand it was completely gutless, couldn't even brake loose a bald set of 215-70 X 15's!. But once it hit 3,000 you better be hanging on because your were going for a ride! :eek: But by then the other guy was L-O-N-G gone..............

Get your compression up to around 9.5 to 1 or so and try get a true 2500 stall converter and at least 3.42 gears, preferably 3.73's. I assume you are running a dual plane intake, if not get a Performer RPM. If that gets you closer to the mark then you can play with cam timing. If isn't better then it's cam time, a tighter LSA would help. If you are "married" to the 3.08 gears and 2,000 converter then it is definitely time for a smaller cam.



Lobe Separation (degrees): 108

That had a lot to do with it I bet............
Very observant, even though I went with a bigger cam with more overlap it was like lighting a stick of dynamite when it got on the cam over the previous cam:

Duration at 050 inch Lift: 238 int./238 exh.
Advertised Duration: 280 int./280 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.474 int./0.474 exh. lift
Lobe Separation (degrees): 110

Those 2 little degrees in lobe separation difference made a day and night difference in that low compression engine. Throttle response was spectacular even with the 8 degrees more overlap going from 60 to 68 degrees. After that swap I should of either tried more compression or a different cam with another 2 degrees less in lobe separation. However by far the easiest and cheapest way to make use of that .484 cam would of been a set of low 4. something gears. Kind of makes me want to build that engine over again w/more compression and better heads.
 

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Hippie said:
Good manifold and carb for low end. Never tried milling the 882's personally, been 20 years or so since I owned any. You should be able to skim a little off them though and run a steel shim head gasket, it can only help. I'd check your local machine shops that do work for the street stock / bomber class dirt track racers. They should have lots of experience with 882 heads and how far you can safely mill them. What are you running for pistons and how far below the deck are they at TDC? The little bit you mill your heads and the thinner gasket shouldn't affect your valvetrain enough to need different pushrods. Cam change and thinner head gasket would be a lot easier and cheaper...............especially if you have it apart already.

My old room mate had an 8.5 to 1 350 very similar to yours back in the 80's, same heads, intake and carb but if I remember right with a Speed Pro cam just like the Summit 1103 cam, 214/224 @ .050" on 112 LSA . It was in a '74 El Camino that orignally had a 454 and it still had the stock big block converter, a TH400 and 2.73 posi. It would roast the tires at will and lay posi for 2 blocks on a hot day ( Much to the dismay of our land lady who lived next door! :spank: )
i bet the 13 inch turbo 400 torque converter had alot to do with it
 

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Warrant said:
Hmmm well w.t.f.
Warant, you think about it, a factory muscle car grind from mopar is:
Basic Operating RPM Range: Idle-5,800 RPM
Duration at 050 inch Lift: 228 int./235 exh.
Advertised Duration: 268 int./276 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.429 int./0.444 exh. lift
Lobe Separation (degrees): 114

and a stock 360 4bbl cam had .430/.444 lift and 268/276 advertised duration. Your LSA gives you a smoother idle, less overlap and such. However putting some gears in the rear get that car moving quicker, easier and help that engine get to the rpm range where it will do more good a lot quicker than the 3.08 gears you have now. Button it up and swap the gears, save your money for the regular unleaded your going to be able to run with the 8.5 compression. More money for gas = more miles with smiles.
 

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72 Nova, 65 Rambler, 37 Chevy
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Discussion Starter · #19 ·
Hippie said:
Lobe Separation (degrees): 108

That had a lot to do with it I bet............

QuenchPiston said:
Very observant, even though I went with a bigger cam with more overlap it was like lighting a stick of dynamite when it got on the cam over the previous cam:

Duration at 050 inch Lift: 238 int./238 exh.
Advertised Duration: 280 int./280 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.474 int./0.474 exh. lift
Lobe Separation (degrees): 110

Those 2 little degrees in lobe separation difference made a day and night difference in that low compression engine. Throttle response was spectacular even with the 8 degrees more overlap going from 60 to 68 degrees. After that swap I should of either tried more compression or a different cam with another 2 degrees less in lobe separation. However by far the easiest and cheapest way to make use of that .484 cam would of been a set of low 4. something gears. Kind of makes me want to build that engine over again w/more compression and better heads.
This confuses me....I thought having like a 114LSA brings the power range down in rpm. While having like a 108LSA will make more power higher in the rpm range. I would think that with my motor, 8.5CR and the 224*, I would want the 114, Which is why I got that cam. It makes no sence to me on why having 108 would be better. Care to explain this?

Anyways... I put the motor back together on how it was before. And I know this is probaly overkill but it is a future investment for the 400(this motor is to get me goin untill 400 is built) I got a 10 inch 2700-3000 stall converter (and a cooler) I think this will really wake it up.?

As for gears, I will still be using the 3.08s for a short while. But I need a recomedation... 3.73? 3.90? 4.10? I can live with any of those. (Im 17 and not driving 70mph very much on long trips) I also think any of those will work fine for the 400 too.
 

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Analog man in a digital world.
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Somebody else could probably explain it better but in a nutshell on shorter duration cams tighter LSA can help the low and mid range because you are still maintaining short "overlap" when both the intake and exhaust are open thereby reducing mixture lost out the exhaust and boosting "dynamic" or cranking compression which helps the low and mid range and thereby throttle response. As duration goes up overlap increases and you need the wider LSA to decrease overlap and help maintain the low and mid range. A cam with 110* LSA will give a little rougher idle than the same cam with 114 but on a short duration cam it can also give better low end power. Take a look at the Comp cams HE series, they're ground on 110 LSA and have a lopey idle yet they are well known for their strong low and mid range.

I had a similar cam with 226 Dur. @ .050, .480 lift and 111* LSA in a low comp. 383 and it was a low and mid-range torque monster. It had just a hint of a lope at idle but it idled slightly higher and really needed a looser converter but the throttle response was right there and it would light the tires at will from any RPM even with a stock TH350 converter in the TH400. A friend built a 406 with a little more comp. and a similar cam but with 114* LSA and while it performed well on the bottom end it didn't have the "explosive" ( mild exaggeration but...... ;) ) throttle response my 383 had even though his 406 was in a lighter car with the same gears.

It's actually a bit more involved than that and I hope I haven't oversimplified but I'm at work with no reference material in front of me and I haven't had coffee yet so I'm shootin' from the hip but hopefully this will make it a little clearer. At least until you can get an explanation from somebody that knows what the hell they're talking about. ;) Short duration wide LSA cams have their niche as well, silky smooth idle, high manifold vacuum with strong mid range and top end, etc. Cam selection is probably THE single hardest decision to make on your car. It can make or break your combo. :drunk: As far as gears it's hard to go wrong with a 3.73 for a street performance car, especially if you plan to put an OD trans in later.

OK guys, let me have it, where'd I screw up?
 
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