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Author Topic:   15 inch cam?
rogracer2
Dirt Maniac

Total posts: 119
posted July 07, 2005 10:27 PM  
I think I've narrowed my choices to 2 different ones- problem is...I'm still unsure if these cams will make 15 inch vac at 750-1000 rpm. If anyone uses these cams, do you know what kind of vacuum you get?

1. Speedway Motors 915-113434
2. Comp Cam 12-238-2

I'm running a 3600 lb car on a 1/4 mi track with a 4 barrel carb.

J3
Dirt Maniac

Total posts: 188
posted July 08, 2005 07:34 AM  
I don't know about the speedway cam, but with the comp cam you shouldn't have a problem pulling 15 at 750 rpm. Will prolly pull around 17-18 @ 750. You could even go up a size to the 12-242-2 (XE268H) and that cam will still pull 15 @750 and about 17 @ 1000 R's.

J3
Dirt Maniac

Total posts: 188
posted July 08, 2005 07:35 AM  
OH, I forgot, those numbers are with a 2bbl carb. SHould be a little more with a 4 bbl.

DangerZoneRacing
Dirt Maniac

Total posts: 176
posted July 08, 2005 11:45 AM  
I run a comp cam 12-330-4 and pull almost 15 of vacuum. good cam....pulls hard on upper rpm's.

sc1 racing
Dirt Freak

Total posts: 419
posted July 08, 2005 04:34 PM  
can you run a solid lift?


rogracer2
Dirt Maniac

Total posts: 119
posted July 08, 2005 08:25 PM  
[QUOTE]Originally posted by sc1 racing:
[B]can you run a solid lift?
---------------------------
No, hydraulic only.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted July 08, 2005 10:40 PM  
Have you considered the Rhoades variable duration lifters??? I have been told that they can add around 2-3 inches of vaccum.

El Santo
Dirt Full Roller

Total posts: 36
posted July 11, 2005 11:15 PM  
From personal experience I would run the comp 12-238-2. I have won over 20 features and a points championship with that camshaft. When I ran that cam it pulled about 17.5" at 1000 rpm's. I tried about 5 different camshafts and when I put that camshaft in I gained an extra 2 car lengths on restarts. If you never intend on going over 6000 rpms then this cam will work excellent.

sc1 racing
Dirt Freak

Total posts: 419
posted July 12, 2005 07:13 AM  
we tried the rhoads lifters in a friends car. it lost all low end power, and never could get it to turn the r's it was before the rhoads lifters. so i would say they are a waste of money, and after playing with timing, tunning carb we still didnt gain but 2 lbs of vacum.

now we are running a solid lift cam with hydraulic lifters. since the class call for hydraulic and has a lift rule, and car pulls 19 vacum at 1,000, passes the lift rule, when not running you can push the top of the rocker you can see its hydraulic, and has unbeleivable power all around..4 feature wins out of 6 races, and getting stronger..

anytime you run a hydraulic cam loose you are just asking to destroy lifters..

theslowguy
Dirt Full Roller

Total posts: 30
posted August 03, 2005 07:40 PM  
total seal gapless rings advertise a 5in vacuum gain, anyone ever try them to verify this?

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