Visit The Dirt Forum for More Information

Author Topic:   355 ci 9:1 compression
Dirt Roller

Total posts: 7
posted December 10, 2005 09:04 AM  
how can a person get a 355 9:1 engine to run hard this is our limit on engines this year must be cast iron manifolds and 2bbl intake

Dirt Forum Champ
Total posts: 5510
posted December 10, 2005 09:20 AM  
Make sure you read all the rules in case you are limited to what Carb, Head, and Cam you can use. Not much sense in trying to do something that is disallowed.

Dirt Maniac

Total posts: 191
posted December 10, 2005 06:36 PM  
also gotta plant the power to the clay

Dirt Forum Champ
Total posts: 649
posted December 11, 2005 03:31 PM  
Use as many LW parts as possible/allowed (crank, rods, pistons flywheel etc). Pick the best heads your rules allow and call a cam manufacturer's tech line to get a cam matched to what you have for heads, gears etc. Turning it over 6000 with a stock 2bbl and iron manifolds is a waste of time. Getting the internals light will let it spool up faster off the turns. The key will be the cam. Many use the 'bigger is better' theory which usually just slows you down.

Dirt Roller

Total posts: 7
posted December 12, 2005 08:31 PM  
thanks guys for the info . after looking at the rules any castiron gm heads allowed 76cc or larger ,must be factory gm 2bbl intake castiron also ,and castiron exhaust , as far as carb must be oem 2bbl so i bought a 500cfm rochester that has been reworked by jet performance ,as far as the cam goes i got a speedway cam not sure of the number but the specs are gross valve lift int.502&exh.516 dont know if this will help or hurt ? anyother hints would be greatly appericated

Dirt Forum Champ
Total posts: 5510
posted December 12, 2005 10:10 PM  
That particular cam is on the ragged edge for 9:1 compression. Maybe too much for cast iron manifolds. You didn't mention what sort of budget constraints you're under, so: Like Raz_900 said, keep everything as light as you legally can, including the car; Figure out what parts combo you're using, (heads, intake, carb, transmission, and final drive ratio, vehicle weight, etc.; and call a reputable cam grinder for their recommendations. Without knowing this stuff, nobody's set-up recommendations are going to help.

You can build a 9:1 7000 rpm screamer with no torque and a two-minute wind-up, or a 9:1 stump-puller that runs out of breath at 4500 rpm, or if you "guess" at it you can miss on both.

The key is to make your car run where your engine wants to run, and gear accordingly, not necessarily where someone else's does

[This message has been edited by Normal Sullivan (edited December 13, 2005).]

Dirt Full Roller

Total posts: 63
posted December 22, 2005 09:51 PM  
what is the 9:1 stump puller/ screamer would like info on 9:1 engines thanks

[This message has been edited by bigdozer (edited December 22, 2005).]

Normal Sullivan
Dirt Forum Racer

Total posts: 87
posted December 22, 2005 11:20 PM  
PM me.

Back to the Archives