327 rear main leak and more leaks
I have a 1967 Chevelle 327, frame off restoration. I purchased the car 3 years ago as a nut and bolt, original 24,000 mile frame off restoration. Car looks good, BUT. The engine is, i was told rebuilt. After 500 miles the rear main started to leak, at the end of last year every seal in the engine was blown. Intake, oil pan, timing cover, valve covers, oil pump and rear main approx 1500 miles since restored. I had the engine pulled and disassembled and discovered that the PCV port in the intake manifold was blocked off by a plate under the carburator. Don't know why this would be done?. Purchased a Felpro seal kit, and a double lip, offset rear main seal. re-assembled and repainted everything. re-installed the engine, (this was done by a shop, $1000.00 + gaskets, oil, antifreeze and paint). They let the car run for over an hour, no leaks. Then another 1/2 hour and still no leaks. Drove the car home 1 mile, parked it and 3 days later took it out to clean it up and I have a pool of oil and it looks as if it is coming from the rear main, dripping out through the inspection cover. I was present when the work was done and feel the rear main seal was properly installed.
Can anybody give me any thoughts. My only possible thought is that the crank was polished up the first time the engine was rebuilt and the seal is to big. The only problem there is it originally took 5-700 miles to leak and nothing has changed. But 1 mile????????
Also any thought on why the block off plate would have possible been installed. I am assuming this let pressure built in the engine and blew out all the seals, but why would you put it there to begin with????
Any help would be appreciated. This car is becoming a money pit