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Old 07-21-2002, 09:08 PM
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Post SBC 270H Comp Cam

Need info. on this cam if anyone has used it with the combination of a 350, auto trans and power brakes ect. If you have used or have one let me know what you think of it.
Gene

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Old 09-20-2011, 12:36 AM
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cams

give some more specs on your 350 motor 72vette

I am running a 68 327 sbc with lunati 60102 voodoo cam with 2.02 heads cast 68 ported and polished with 64cc and it kicks butt, and i have heard these voodoo cams out perform comp cams on many dyno runs pretty aggressive ramps on lunati grinds. My 68 chevelle pulls hard up to 6400rpm with this cam. But there are many who like comp cams. That is my 2 cents!
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Old 09-20-2011, 05:51 AM
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270 grind has been around forever. There's a reason for that.
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Old 09-20-2011, 07:06 AM
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That cam (270H) would need about 9.5:1 cr, headers, 2600 stall, 3.55 gear, and aftermarket intake.

if you use the stock 72 350 (low cr) with 3.08 gear, th400, and stock converter then get a smaller cam.

with an otherwise stock 72 vette setup, I would use the compcam 260H.

If you have headers and a little more stall, you could get by with the 268H.
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Old 09-20-2011, 12:52 PM
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270H cam is mild midrange camshaft. Good for street use with power brakes.
It will give you a slight lopy idle. Works great with automatics.
Hope this helps
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Old 09-20-2011, 07:01 PM
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I agree that it is a very good cam. Used it in a stock bore 350 with FT pistons, z-28 alum intake, 461 heads, 600 holley, 1 5/8 headers with 2 1/2 exhaust. Had a slight lope in gear but smooth otherwise. Comp says its the largest cam with a stock converter. I had a B&M Breakaway and 3.73 gears.
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Old 12-05-2011, 08:47 PM
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270h

How would this cam do with on my 300hp sbc350 with stock 1.94/1.5 heads, 10:1's, TH350 with 3600 stall, 3.08 rear gears, performer intake/ quadrajet and power brakes? Would I have to upgrade my valve springs?
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Old 12-06-2011, 05:28 AM
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Quote:
Originally Posted by CHEVILLAC
How would this cam do with on my 300hp sbc350 with stock 1.94/1.5 heads, 10:1's, TH350 with 3600 stall, 3.08 rear gears, performer intake/ quadrajet and power brakes? Would I have to upgrade my valve springs?

I think you have a mismatch in parts.

stock heads, 3.08 gears, performer, qjet, power brakes requires a small cam.

10:1 cr, 3600 stall requires a bigger cam.
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Old 12-06-2011, 10:24 AM
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Quote:
Originally Posted by 454C10
I think you have a mismatch in parts.

stock heads, 3.08 gears, performer, qjet, power brakes requires a small cam.

10:1 cr, 3600 stall requires a bigger cam.
I disagree. I think it perfect cam for the motor. The only thing I would change is the converter. I would go for a 2200 rpm. 3600 is a little steep.
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Old 12-06-2011, 11:22 AM
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Quote:
Originally Posted by CHEVILLAC
How would this cam do with on my 300hp sbc350 with stock 1.94/1.5 heads, 10:1's, TH350 with 3600 stall, 3.08 rear gears, performer intake/ quadrajet and power brakes? Would I have to upgrade my valve springs?
The actual compression ratio (or CR) that you will have when using pistons rated at '10:1' or whatever, depends mainly on the combustion chamber size and the piston volume and to a lesser degree on the deck height, cylinder overbore and head gasket compressed thickness and bore diameter. So a couple questions will help pin the CR down:

Do you know if the block or heads were ever decked? If so, how much was removed? Is the block bored oversize?
Do you know the piston volume, or if not are the pistons flat tops, dished or domed? Do you have a part number for them?
Do you know the size of the chambers, or if not what is the casting number of the heads?
Do you know the head gasket specs or have a part number for them?
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Old 12-06-2011, 08:06 PM
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Quote:
Originally Posted by CHEVILLAC
How would this cam do with on my 300hp sbc350 with stock 1.94/1.5 heads, 10:1's, TH350 with 3600 stall, 3.08 rear gears, performer intake/ quadrajet and power brakes? Would I have to upgrade my valve springs?
I meant 2600 stall
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Old 12-06-2011, 08:16 PM
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I bought that cam in 1989 right after it was introduced. 400, 8.5 comp., 3.23 gears, stock converter. I used Rhoades lifters though. Idle was decent enough for street use. If I remember correctly it had 14" if vacuum. The car ran good but would have been a lot better with a stall. (2.10 60 ft. times, 101 mph. @ 1/4mile) More compression would have been a good idea too, but I was only 19 and didn't know about that stuff. In my opinion I think it would work great in a 10.0 comp. motor.
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Old 12-06-2011, 09:34 PM
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My exppireince with the mag 270 is that it is a race cam. Making 400+ hp, no low end, but with a 3500 stall you could brake torque it. Wind it up and let go. HOLD ON.

Going to the vortec 906 head made more difference than cam, starting out on my stock sbc build. The Vortec head upgrade total cost was a little over 325 with without some gaskets. Going from a .380/.400 lift to .420/.442" cam made a all around increase in the operating range, even the off idle was better. Cam is 100 without some gaskets. The heads were the secret, The blistering top end power was like a monte carlo ss to a corvette. Heads are the best way there.
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Old 12-30-2011, 06:24 PM
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cam selection

Ok, I've done some figuring on my motor. Heads are 3932441 castings with stock 76cc chambers, 1.94/1.5 valves with edelbrock 5703 valve springs. Pistons are flat tops with 4 valve reliefs each, 5cc. Block has not been decked, guessing at .25 from piston to deck, 4" bore, 3.48" stroke. .039 gasket. I get 9.5:1cr. Edelbrock Performer RPM intake, Edelbrock 1406 600cfm carb, 1-5/8 primary headers with 2-1/2" exhaust with Smithy's glasspacks, TH350 trans with 2600 stall, 3.08 rear, power brakes. This is in a 1961 Chevy swb that never hauls anything, it's my daily driver but I drive it like it's a Camaro so I want it fast off the line but good torque and power through 5500 rpm. I'm thinking the Lunati Voodoo 60102 would be a perfect fit. What do you guys think?
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Old 12-30-2011, 09:56 PM
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would be a good cam to use with a 3.08 gear and 9:1 cr. 9.5:1 is a little high for that cam and could detonate. A 268H compcam would match the stall and compression better.

are you sure about 9.5:1? I'm thinking it should be closer to 9:1.

716cc cylinder
76cc head
8cc head gasket
4cc piston below deck
5cc piston reliefs

(716+76+8+4+5)/(76+8+4+5)=(716+93)/93=8.7:1

The 60102 cam should be perfect!
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