Visit The Dirt Forum for More Information

Author Topic:   I need cam, 15 in minimum vac.
Dirt Roller

Total posts: 13
posted October 01, 2002 10:56 AM
Im in the process of building a sbc 355 w/JE Forged Flat tops 9.5 to 1 w/76cc 441 heads. Cast iron 2 barrel intake with Rochester 2 barrel. The rings are Total seal Max seal rings. All stock valve train except for springs which are H-11 tool steel Crane. The stroke is 3.48 and the rods are 5.7, My only worry is the rules specify we need 15 inches of Vacuum at 700 RPM, Can someone please give me advice on what brand cam to run and what size to stay somewhere around the 15.5 to 16 inch range. I really appreciate all the help i can get. The cam i was looking at for now was a Crane Powermax cam and lifter set, hydraulic, Advertised Dur. 276*/284* with a lift of .454/.480. Any other tricks will also be considered. Thanks.

[This message has been edited by bncars10sen (edited October 01, 2002).]

Dirt Full Roller

Total posts: 26
posted October 01, 2002 08:58 PM
Try calling comp cams. their helpline is very good and they have LOTS of information about their products. I personally wouldn't be able to tell you the vacuum your cam would make in that engine cause i just haven't ever check all of the engines that i've stabbed cams into. But simply by guessing i'd say that you COULD go a LITTLE bit bigger than what you have picked out there. Hope this helped some.

Dirt Freak

Total posts: 408
posted October 02, 2002 06:01 AM
Camcraft. Just click the link that scrolls by on the top of these pages. Charles will help you beyond what any big cam maker will, and he makes power and not just promises.
Tell him I sent you, and he'll set you up right.

Dayton Umholtz, owner
Kinetic Performance

Dirt Freak

Total posts: 330
posted October 03, 2002 03:31 AM
I agree call Charles with Camcraft, he'll help you out.

Smith Racing Team

Dirt Maniac

Total posts: 180
posted November 02, 2002 11:04 PM
schneider cams is superior. And they will help out a lot very good tech support and check you pm

Dirt Freak

Total posts: 353
posted November 03, 2002 01:11 AM
Jeez, 15" @ 700 rpms? Try Hoover or Eureka!

Dirt Forum Champ
Total posts: 620
posted November 03, 2002 08:06 AM
a lot of guys overlook this. if you want to pull some big vacuum numbers and still make a lot of horsepower, then compression is how to do it. BIG DOMES. with more compression, you can run a bigger cam and not lose all the low speed vacuum. racing gas only though........

rico 08
Dirt Freak

Total posts: 372
posted November 06, 2002 02:03 PM
big domes in my class is a no no flattops only,one trick is bleed down lifters(crane has these)and try to keep lobe center wide around 112-114,i'd definitely keep the .050 duration below 240 deg and anything in the 230 deg range should be fine.

Dirt Newbie

Total posts: 1
posted December 13, 2002 01:01 PM
try a 480 lift cam with a set of rhoads anti pump up lifters

Dirt Roller

Total posts: 24
posted December 13, 2002 09:43 PM
I mud raced in a vac class 15in. @ 800rpm and tried 4 or 5 cams.

The cam i found to be the best was the

270/270-465/465 224 @ .50 sep 106

Compression is a big factor.
(the higher the easer to pull vac)

[This message has been edited by 20bmw (edited December 13, 2002).]

Dirt Full Roller

Total posts: 61
posted December 15, 2002 12:42 PM
Lunati makes a cam 00011 (i think) it should
do that vacuum . 230@.050 .485 lift 114lobe separation ( box grind so it's cheaper)
The lobe separation is the KEY to pulling vacuum. More compression helps also. Call the cam companies, they can help. The special
grind cams will cost more, but they ARE worth it.

Back to the Archives