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Author Topic:   valve angles
BIGG C
Dirt Maniac

Total posts: 114
posted October 31, 2005 02:28 PM  
What are the best angles to put on the back of the valves and the seats of a stock class motor. No porting and polishing allowed. Pocket porting is allowed. Will narrowing the valve guide help? BIGG C

leapinlizard
Dirt Freak

Total posts: 402
posted November 01, 2005 08:16 AM  
5 angles for low lift flow. Even more important in limited lift cam rules. Removing any obstruction to total flow will increase in power.

BIGG C
Dirt Maniac

Total posts: 114
posted November 01, 2005 06:25 PM  
What has more effect, cutting the seats or backcutting the valves? Can run any hydrolic cam so will be limited by lifters. BIGG C

leapinlizard
Dirt Freak

Total posts: 402
posted November 02, 2005 07:39 AM  
Cutting the seats will show more inprovment's alone than backcutting valves at mid lift. The seat cut's provide better low lift flow when limited to a production head with minimal port material to reshape. Can you bush the lifter bores to the ford .904 lifter? If so you can get more lift with the same duration to increase torque in the usable RPM range. If bushing lifter bores is a option and you have good heads, backcutting valves would provail over increase in power over a 5 angle seat cut. Both would be ideal.

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