Desktop Dyno Help
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Senior User
Joined: Jun 2001
Posts: 150
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From: Watertown, NY
Desktop Dyno Help
Ok so I found out that I was calculating the CR on the motor I was using on Desktop Dyno wrong. I found out from this site that the stock deck clearance from the top of the head to the top of the piston on TDC is .028" stock. It was on one of the posts in here somewhere so Im going on that. It also said that the stock combustion chamber was 69cc's. So I put the deck clearance of .028" into my calculations and used a .041 thick FEL-PRO gasket with a 4.100" bore, a combustion chamber of 60 cc's (that what the Performer RPM's have) and came up with 10.71 to 1. Are these numbers I am using right? Where can I find them. What is the tock gasket bore? I try to put the stock specs in and it keep coming up higher that what it should be. (I think its supposed to be 8.8 to 1) I think its gonna be because I dont have the right gasket bore. Assuming this CR is right, is it too high for the stock bottom end? With these edelbrock preformer RPM heads, performer rpm intake, 750 cfm carb, roller retrofit cam from crane, and headers with open exhaust this combo pushes nearly 500 ponies. [487 HP @ 6000 RPM, 468 ft*lb @ 4500 RPM]
Thread Starter
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Senior User
Joined: Jun 2001
Posts: 150
Likes: 0
From: Watertown, NY
Its a 1988 351W engine. The pistons are stock so I am assuming that they are flat topped...? I know that the stock CR is 8.8 to 1 so I think im gonna put in values for the gasket and the deck clearance until it comes out what I want. But if anyone knows the stock values for the deck clearance, gasket thickness, or gasket bore I would appreciate them. Thanks.
Ryan
Ryan
