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Author Topic:   VACUME RULE
baddracing42
Dirt Roller

Total posts: 20
posted March 07, 2004 08:16 PM  
OUR TRACK HAS STARTED RUNNING A 18 INCH VACUME RULE IM RUNNING A 350 SBC BORED 30 OVER ANY IDEALS ON A GOOD CAM TO RUN ON A 1/4 MILE RED CLAY TRACK

bigcityracer
Dirt Freak

Total posts: 431
posted March 07, 2004 09:29 PM  
Never heard such a high vacuum rule. I would call cam manufacture for some ideas

Special Ed
Dirt Full Roller

Total posts: 63
posted March 07, 2004 09:52 PM  
We had to run 17 inches of vacum one year. We got a special grind from Comp and with proper carb adjustments it would pull up to 21 inches. It did not sound radical at all but I won more races and money with that cam than any other. It had all kinds of power. It was in a Ford but Comp will have a similar profile for a Chevy. If you would like I will try and get the part # off of it for you. By the way, we ran it on a 1/4 mile dirt also.

avila
Dirt Freak

Total posts: 217
posted March 08, 2004 10:11 AM  
call comp cam guys. they will work with
you to get a customer proper grind on
the cam.

jay116
Dirt Freak

Total posts: 428
posted March 09, 2004 11:45 AM  
we ran comp cam for years with several wins on this cam part no cca 12 210 2 from summit218/218 dur. at 050 454/454 liftyou might have to run rhodes lifters we did pulled 18 1/2 most of the time we also had a lift rule no bigger than a 460 runs good hits hard good luck

Special Ed
Dirt Full Roller

Total posts: 63
posted March 09, 2004 03:24 PM  
The cam I ran is 222 and 224 duration @50 and 494 and 500 lift. We ran completely stock lifters and pulled 21 inches.

Raz_900
Dirt Forum Champ
Total posts: 635
posted March 10, 2004 07:43 AM  
If you run a wide LDA it should help vacuum too. A tight angle, like 106 or 108, will cost you a couple inches at idle. I'd bet if you got a custom cam ground on really wide angle, like 116, you could run a pretty high duration and still pass.

Scoot
Dirt Forum Champ
Total posts: 517
posted March 10, 2004 03:51 PM  
I have to agree with Jay. Support our sponsors. Charles the owner of Camcraft will help you out. I've bought from them the last two motors I've built or had built. I've Had good luck with pulling the required vacuum. Something my engine builder mentioned the other day. You can use different ratio rocker arms on the exhaust to make you pull more vacuum, like use a 1.6 on the intake and a 1.5 on the exhaust.

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Scoot
Smith Racing Team
870-365-5989

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