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Author Topic:   Question about proper cam specs
mod24racing
Dirt Newbie

Total posts: 3
posted March 27, 2005 12:48 PM  
I was just wondering what the proper cam would be for my engine. This is an alcohol engine for a ump modified. The compression will be about 14:1, I'm not exactly sure but that is what we were aiming for.We were looking at having about 650 hp. Rpm range for this engine is from 5000 to 7000. The engine specs are:
350 block
forged 383 stroker rotating assembly
w/wiesco pistons.
6" H-beam rods
pro topline 49 cc heads
victor jr intake

I usually race on a 3/8 mile track.
If anybody can help me out I would appreciate it. Comp cams make really good camshafts so if anybody knows the right part # for my application I would appreciate the info.

chomme
Dirt Freak

Total posts: 300
posted March 27, 2005 05:35 PM  
quote:
Originally posted by chomme:
I'd run 260/264 @ .050 or 262/266...and shoot for around .700" lift at the valve and a 106 lobe center. I'd run a shaft rocker setup with it, but that's just me. Remember on an alky motor to have the timing at .050 closer than on a gas motor.

Thanks for the info. I was looking on the comp cam website and the part #'s that are close to what you are suggesting are 12-612-5 12-517-5 12-687-47
Which do think would work best?

chomme
Dirt Freak

Total posts: 300
posted March 28, 2005 12:19 AM  
Bill Hendren's is in the hospital, he had a stint put in his heart .He 's doing fine and will be home in the next few days. I run the same combo and use a 12-505-5 comp cam and love it.I have a 410 that has the 12-515-6 in it.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted March 28, 2005 02:29 PM  
ISKy has an off the shelf solid flat tappet cam thats 258/262 @ .050 and .570/.580 lift. Also a 254/258 .560/0.570. if you wanted to go a little smaller, the first on might be a little big for a 3/8 track. We ran the first one of these for years and it pulls hard in that size motor. We usually turned aroudn 7000 with it but would go to 7400+ if we needed to. Always wanted to try 1.6/1.5 split rockers on it but never got the chance, rod broke first....lol.

Id look for intake duration around 255 at .050 and keep exhaust within 4 degrees of that on alky.

mod24racing
Dirt Newbie

Total posts: 3
posted March 28, 2005 04:30 PM  
quote:
Originally posted by dirtbuster:
ISKy has an off the shelf solid flat tappet cam thats 258/262 @ .050 and .570/.580 lift. Also a 254/258 .560/0.570. if you wanted to go a little smaller, the first on might be a little big for a 3/8 track. We ran the first one of these for years and it pulls hard in that size motor. We usually turned aroudn 7000 with it but would go to 7400+ if we needed to. Always wanted to try 1.6/1.5 split rockers on it but never got the chance, rod broke first....lol.

Id look for intake duration around 255 at .050 and keep exhaust within 4 degrees of that on alky.


Thanks for all the info guys

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