Is .003 main bearing oil clearance too large?

engine is in 2000 lb 1/4 mile car

Gary,

Many Buick racers are using .003” clearance, and have been fine. A stock oil pump w/ booster and regulator should handle the oiling duties. My stroker came with .003” clearance on the rods and mains from TA. It uses the booster and regulator, but does have one of the new and improved timing covers.

I also went back through several GSCA engine-building articles to see if there was a consensus on street-strip bearing clearance. Three said .002 on the mains with .0025 on #5, and .002 on the rods for a street-strip engine. One gave .0015-.002 on the mains with .0005 more on #5, and .0015-.002 on the rods for a street-strip engine.


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Steve B.
GSCA #2173 (1986)
67 GS 525 Stg IV
66 GS Convertible
65 GS HT
63 Riv

Like Steve said for a Racing engine, that is probably okay. For a driver/cruiser, that seems to be a large clearance.

-Bob Cunningham
bobc@gnttype.org

Thanks Bob and Steve for your answers.

I have another question,the Buick 455 on propane
What is the best cam specs for most HP and Torque. 10:1 cast pistons, (2) CA425 mixers on Offy dual quad intake,1969 430 stock heads
with 455 (1.55)rockers/shafts,lifters,push rods
Thanks