Help, Fords and Rear main oil leaks

I'm helping friends prepare two different cars for the Great American Race.<P>The first is a 1936 for with 85 Hp V8 from 1937 in it.<BR>Last week we put the thing back together. <BR>After about 300 miles the rear main leaks oil like the Exxon Valdez.<P>Any experience out there with the rear main seal set up on these.<BR>This is my first Flathead Ford?<P>Second car is the 1929 Ford Speedster that the AACA Museum is sponsering in the race.<BR>It has a Ford B block with a Miller Head.<P>Also leaks from the rear main seal area. <BR>After we fix the '36 we're gonna tear into the B Block. Any hints greatly appreciated!<p>[ 05-13-2002: Message edited by: boettger ]

I have never worked on an flathead v8, however I do own a Model A.<BR> On the A engine, many things can help it to leak. 1. excessive bearing clearance.<BR> 2. excessive end play on the crank (back and forth motion pumps out oil 3. rear main return tube loose or missing 4. return tube not submerged in oil. 5. running at high rpm. (installing a pcv system can reduce this ) and last but not least 6. they can leak out of spite Bill

Excessive crankcase pressure can contribute also, especially if the engine is not broken in yet.<BR>Have you checked for any blowby coming from the oil fill?