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Shuie Shuie is offline
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Join Date: Feb 2003
Location: ....down Highway 61
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39mm intake ports too big for a 3.2 street motor?

Here is how my motor is shaping up:

3.2 Max Moritz short stroke, single plug, 9.8:1, GE40 cams, and MFI from a 2.7 RS. This engine was previously setup to run with 40mm Weberís instead of the MFI.

Grady has lined me out on how to make the MFI work.

My current issue is that the throttle bodies on my MFI system are bored to 39mm and I have a completely refreshed set of small port (34mm intake ports) SC heads that were used before with carbs.

This will be at least a 90% street motor. Are 39mm intake ports too big for this engine? Should I look for a smaller set of MFI stacks and throttle bodies? Iím not entertaining the idea of changing cams or pistons at this point.

I know that drivability and streetability are relative terms and that you must look at the entire engine as a system instead of trying to make decisions based on individual components.

What am I going to lose if I go to the bigger 39mm intake ports? How big of a difference do the bigger ports make on a '78-'79 SC compared with a '80-'83 SC?

My guess is that I will lose some low end grunt and I will have a little more breathing room in a rev range that a street motor will probably never see.

Any thoughts or advice is appreciated.
Old 12-21-2004, 07:28 AM
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