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Old 09-11-2007, 11:00 PM
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Cam selection for pickup

Hi everyone,

Lookin at swapping a different cam into my pickup. Current set up is:

86 chevy 4x4
350
automatic
"487" heads 76cc chambers 2.02/1.60 valves
performer intake
flat top pistons
headers
9 to 9.5:1 compression?
q-jet
31x10.5x15 tires
3.42 rear gear

Currently has an edelbrock performer cam: 204/212 .420 lift intake/.442 lift exhaust.

I was thinking I could get by with a little more cam to make a significant change in power. Mainly used off road with the occasional highway/street cruising. Looking at Comp's line of extreme energy or extreme energy 4x4. Any suggestions? Thank you.

Chevy 21

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Old 09-12-2007, 05:33 AM
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I don't think you'd want much more cam than you have if you want to keep low end power for offroading. You could step up about one notch to the 212/218 or 218/224 range, but above that you will begin to lose low end power that you need.

I think I'd put my money into lower gears, probably about 4.10's as a good compromise. It won't make highway cruising very comfortable, but it will help your off roading quite a bit.

A switch to 4.56's would be even better for off-road, but wouldn't work well on the highway with 31's. Then it would be time for 35's and a lift kit .

Bruce
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Old 09-12-2007, 05:55 AM
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I agree with 75gmc, with those heads and that compression I don't see much if any gain by going to a bigger cam for what you're looking to do. It might make more power at a higher RPM but without changing gears and putting in a looser torque converter you would lose the power where you need it most.
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Old 09-12-2007, 07:46 AM
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You have the perfect cam already.

I would put on some 64cc, 180 afr aluminum heads or go to a 383 or 406 if you what more power.

I think you have about 8.5:1 cr with 76cc heads.
717cc /cylinder
9cc head gasket
4cc piston below deck
6cc valve reliefs
76cc head volume

(717+9+4+6+76)/ (9+4+6+76) = 812/95 = 8.5

with 64cc heads
(717+9+4+6+64)/ (9+4+6+64) = 800/83 = 9.6
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Old 09-12-2007, 07:55 AM
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Getting different gears would be nice. Probably a little pricey though. Just seems that I am running out of steam a little early. Right around 4800 rpms is pretty much where it cuts off. I figured a little bigger cam could net me more power.
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Old 09-12-2007, 05:01 PM
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If you are willing to switch to 3/4 ton axles (8 bolt), you might find a set of used axles with 4.10 gears. A 3/4 ton full floating corporate 14 bolt rear axle and a HD Dana 44 front axle was a fairly common drivetrain on heavy duty 3/4 ton and 1 ton trucks in the mid to late 70's.

Brucd
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Old 09-12-2007, 06:11 PM
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More cam will likely slow the truck down because of moving the intake closing point to a later closing position and capturing less mixture which will result in lower cylinder pressure. I am computing your c.r. based on 8cc gaskets, 5cc piston eyebrows and 5cc's in the piston deck height (pistons 0.025" in the hole at TDC) and come up with 8.61:1 static c.r.

If you want more cam, you will need to increase the static c.r. with different heads or whatever to take advantage of the later closing point and extend your rpm range.

That's just my opinion. I could be wrong.
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Old 09-12-2007, 09:11 PM
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Your duration is right where it needs to be but you could benifit from more lift, the extreme energy 4X4 cams work really well and are more aggressive with higher lift values. I run a small one in my 350 4X4 with 33's and 3.73 gears and it pulls really strong from 800 idle to 5K with marginal heads.
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Old 12-23-2008, 09:00 AM
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I agree with techinspector im runnin the performer cam in my truck now(355) with the performer intake and edelbrock 1406 carb it is a 78 3/4 ton 2wd(882 heads) granted its not a lifted 4wd but I have steep gears ( I really think they're 4.10 cause on the interstate it just howls and I have lots a pull with it also with those heads my guess is your only at 8.5ish-1 CR bigger cam wouldnt help ya here if anything maybe put the edelbrock 400 sbc performer cam in there (yes there is such a thing) dont quote me but iIthink it is 214/.214,.442/.442 thats max for you that id go
but id stick with watcha got put some 64cc's on 'er with a 4.10 gear and roll I think you have more fun with a setup like that
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