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cam suggestion..

7K views 89 replies 10 participants last post by  candy63impala 
#1 ·
i know ,another cam topic...
cant make up my mind looking for some suggestions. let me start with what i am working with.
63 impala,350 turbo,2500 stall,321 gear/9" rear. appx tire height - 23"(155/80-13)
383 sbc. .060. zero decked, -.007 dish-kb134, vortec heads,64cc chamber, 185 runner. block hugger headders, 750 holley carb, probaly gonna run air gap edelbrock intake
may have missed something... ask for more info if needed. thanks again... looking for suggestions...(not opinions on bigger tires!!!)
 
#2 ·
What you gonna do with it........

is a major concern. With those tiny tires.....the kind of cam an engine like that deserves.....will smok'em down to the wire rims you gott'um on.
With that engine I would run a flat tappet hydraulic cam and lifters. 235-240ish degree of duration@.050 and lift in the under 500 neighborhood because of the vortec heads. LSA of 108/110 degrees. Its gonna have a killer idle and gobs of HP and torque upto about 6200rpm's.
Let me guess........this is a low-rider! :mwink:
6sally6
 
#3 ·
yes its a lowrider.hence the 13s!

as far as vortec heads and only 500 lift,how come? ive machined the guides down,as far as that restricting me?. i have an edelbroc perf. rpm cam that was in it,i am wanting to know if i should go with that or id like to change it up and get some more hp out of it,while i got the engine out
 
#5 ·
just an fyi....

a +0.060 350 with a 3.750 stroker crank is a 388, not a 383 0.060.

and those piston are +7cc not -0.007 dishes.


with a zero deck you are making around 10.9:1 cr. this will require a cam the size of a compcam 292H (242/242 at 0.050, 501" lift, 110 lsa) to run pump gas.

Your small tires are good, as they will make that 3.21 gear seem like a 3.90 gear with normal size tires. the compcam 292H does best with 4.11 gears so 3.90 is not too far off.

however, that 2500 stall isn't enough. you need a 3000 stall for the compcam 292H. so you have a little mismatch with the stall and compression ratio. However, a cam with 114 lsa and 240 degrees at 0.050 would work with the current compression ratio and stall. as the 114 lsa will smooth out the idle a little (less over lap) and the 240 degrees will shut the intake valve late to reduce cylinder pressure.

a cam like this will require 20 degree of timing at idle and 36 total with vortec heads.

I would not use the air gap if you plan to drive it in the winter as these intakes have very slow warm up. the regular rpm intake is much better for an all weather street engine.

use an oil additive with any high performance cam. use at break in and at every oil change. www.zddplus.com.
 
#7 ·
454C10 said:
just an fyi....

a +0.060 350 with a 3.750 stroker crank is a 388, not a 383 0.060.

and those piston are +7cc not -0.007 dishes.


with a zero deck you are making around 10.9:1 cr. this will require a cam the size of a compcam 292H (242/242 at 0.050, 501" lift, 110 lsa) to run pump gas.

Your small tires are good, as they will make that 3.21 gear seem like a 3.90 gear with normal size tires. the compcam 292H does best with 4.11 gears so 3.90 is not too far off.

however, that 2500 stall isn't enough. you need a 3000 stall for the compcam 292H. so you have a little mismatch with the stall and compression ratio. However, a cam with 114 lsa and 240 degrees at 0.050 would work with the current compression ratio and stall. as the 114 lsa will smooth out the idle a little (less over lap) and the 240 degrees will shut the intake valve late to reduce cylinder pressure.

a cam like this will require 20 degree of timing at idle and 36 total with vortec heads.

I would not use the air gap if you plan to drive it in the winter as these intakes have very slow warm up. the regular rpm intake is much better for an all weather street engine.

use an oil additive with any high performance cam. use at break in and at every oil change. www.zddplus.com.
i forgot to mention,the heads are from patriot performance? got them at alabamacylinderhead.com.. they have 2.02/1.6 and screw in studs. probaly not much winter drivng,itll be garage kept anyways,not a daily driver, may see 1/8th mile everynow and then
 
#9 ·
too 274 degrees of cam duration is too small for 11:1 cr and pump gas.

Do a search on dynamic compression ratio. You will need to know the intake valve closing point (when the valve hits the seat).

I have run 11:1 cr with a 292H and it works with 93 octane.
 
#10 ·
here is a good online dcr calculator to use. It is a pontiac site, but work fine with chevy numbers (bore, stroke, rod length,....)

http://www.projectpontiac.com/ppsite15/compression-ratio-calculator

I get 11:1 cr (static compression ratio) with your setup.

8.67 dcr with a 274 degree cam with 110 lsa (xe274)

8.00 dcr with a 292 degree cam with 110 lsa (292H)

8.67 dcr is too high (in my opinion). 8 is good for a sbc with pump gas.

280 degree cam with 114 lsa makes 8.12 dcr which could work ok with 11;1 scr and your 2500 stall.
 
#12 ·
ap72 said:
The 292 may be the best way to go, though its awfully big for a hyd. flat tappet. The power down low will be soggy, but that's the result of running such a high SCR and so low of a stall.

that is true. The 292H is not good under 3000 rpm.

That is why a 280 with 114 lsa might bridge the problem. as the 114 lsa will smooth out the idle (good for the low stall) and also close the intake valve later (good to the high cr).
 
#14 ·
candy63impala said:
how thick of a head gasket can i run to bring the compression down a bit to run something like the 274 cam? on the comp cams camquest page, im comming up with around 504hp with that cam setup and 10.5:1 comp.
not sure if the pic will show...

you can't do that with a gasket swap, you'll create more problems than you'll solve. Also, that computer generated dyno is VERY optimistic. 460hp for that combo seems more appropriate. I would also skip the wide 114 LSA idea, it will smooth the idle out and perhaps allow you to run on pump gas, but you'll be giving up about 30hp when compared to a cam that more closely matches that combo. The best thing to do is get the rigt cam, and then get the right conv. Don't try to compromise, it just leads to dissapointment.
 
#16 ·
I don't like the Voodoo's for street enignes since they are notorious for failing. If you do everything perfectly right then you can run one and be fine, but more often than not something is compromised and they fail.

Older grind may not give you the same power, but they'll last a lot longer.
 
#19 ·
You keep picking cams that are too small. These cams will make too much cylinder pressure with your setup.

If you don't want to change the stall then get a 280H ground on 114 lsa with no advance ground into the cam. (cost an extra 50.00 for a custom cam, call compcams). They will try to push their xtreme cams, but don't did it.

if you are ok with changing the stall, then get a 292H with a 3000 stall.

Check the specs on over the counter cams. I bet you could find a 280/280 cam with 114 lsa from other cam grinders.

use an oil additive with your new cam. www.zddplus.com. get a case as you will be needed it at break in and at each oil change.

Yes, I agree. avoid xtreme or voodoo cams. too aggressive for a flat tappets. Older slow lift grinds will live longer.
 
#20 ·
Here's a good cheap cam, PAW-221011. It'll give you pretty good performance, last a long time, and is a decent compromise for your combo. Realistically it could use more stall, but any cam that will work well with your engine is going to prefer more stall. Run it with 1.6:1 rockers.

When you get it all together get it dyno tuned on a chasis dyno with the fuel that you plan on using everyday (from the local gas station).
 
#21 ·
454C10 said:
You keep picking cams that are too small. These cams will make too much cylinder pressure with your setup.

If you don't want to change the stall then get a 280H ground on 114 lsa with no advance ground into the cam. (cost an extra 50.00 for a custom cam, call compcams). They will try to push their xtreme cams, but don't did it.

if you are ok with changing the stall, then get a 292H with a 3000 stall.

Check the specs on over the counter cams. I bet you could find a 280/280 cam with 114 lsa from other cam grinders.

use an oil additive with your new cam. www.zddplus.com. get a case as you will be needed it at break in and at each oil change.

Yes, I agree. avoid xtreme or voodoo cams. too aggressive for a flat tappets. Older slow lift grinds will live longer.
so am i looking for more duration then or more lift? whats the worst case from using the small/less stall. i mean how will the engine react to it?
 
#25 ·
i had it assembled and running a few years ago. i tore the car down again to repiant it,and time and money victimized me!. the engine was dissasembled, cleaned up,im going with a new block and vortec heads this time,and a new intake,cause my rpm wont fit the new heads. when i tore it down,the beaings were beat out pretty good i supect from spark knock
 
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