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Author Topic:   Budget Bomb
Pit Bull
Dirt Full Roller

Total posts: 42
posted May 21, 2001 06:04 PM
I am preparing to build a 350 bomb. I have enough parts laying around the shop that are taking up space and need to be condensed into one running unit. My question is about head and valve grinding. I dont really have access to a valve/seat grinder, and was wondering if I could just take a junk set of heads, lap the valves, and run em? Or does having that good ground seal make that much difference? Ive heard that many engine builders dont believe in lapping valves, so im after your opinions...thanks for the help!!

awkwardjeff
Dirt Freak

Total posts: 219
posted May 21, 2001 10:47 PM
The valve seats are the biggest part of any head........the angles these are cut improve flow........as for lapping the valves or not, it depends on how they are cut. and then ground with a stone........todays machine shop have the best cutters nad stones to grind them with that lapping a vavle is a thing of the past.......if you have a otherwise good set of heads with one vavle leaking a little that one valve can be taken apart at home and hand lapped back in to help seal that cylinder back up.
to check this you need to have a motor together and leak each cylinder.......
Bring your heads down and have the shop due a quicky valve job........cheapest horsepower you can buy.

Pit Bull
Dirt Full Roller

Total posts: 42
posted May 25, 2001 08:45 PM
Ive got one more question - in a mildly built 350 (cast intake and exhaust manifolds, quadrajet carb, hydraulic cam) Would upgrading from 1.5 and 1.94 valves to 1.6 and 2.02 make that much difference?

A2KY2K88
Dirt Full Roller

Total posts: 58
posted May 25, 2001 09:21 PM
YOU WONT FEEL ANY DIFFERENCE AT ALL. EVERYTHING WORKS TOGETHER IN A MOTOR, CARB, INTAKE, CAM AND HEADS. YOU ARE VERY LIMITED BY RUNNING A QUAD WITH THAT INTAKE AND STOCK MANIFOLDS.

awkwardjeff
Dirt Freak

Total posts: 219
posted May 26, 2001 12:54 AM
I will agree that you wont notice much of a differance, But I would put in the 1.6 exaust valves.........the exaust need to flow 80-85% of the intake to make good power and torque, the 2.02 would hurt you with the rules you have for intake and exaust manifolds..........But getting the exaust side of the head to flow a little better will help...........
It is a total package deal, I think the 1.6 exaust valves would make you a better package than you currently have.......Jeff

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