Okay, here's the deal... I've been pulling my hair for a couple weeks on this problem. I have a 350 sbc, Holley Contender intake manifold PN300-36, Edelbrock 1406 600cfm, HEI ignition, ramhorn exhaust manifolds and a TH350. Unknown mileage on the motor and tranny. The motor is out of an 83 Blazer.
Originally my carburetor started fuel dumping, but I rebuilt it and now it's fine and the engine is running 20" of vacuum. Added a fuel pressure regulator set at 5.5 psi.
After I rebuilt the carburetor then I started seeing smoke out of the exhaust and it is bluish white. Compression check results showing 155 psi +/- 5 psi. All cylinders within 6.5%.
I Removed the PCV and added a breather, that didn't change anything. Checked the transmission line to the carburetor and that is bone dry also.
When I rebuilt the carb, I changed the cap, rotor, plugs and wires. However, when I did the compression check I found all my plugs to be black and sooty looking.
It seems like the longer I let the motor idle the worse the smoke gets when I rev the engine and let it back down. I've been leaning towards valve seals and guides, but am unsure that all my seals would just go bad at the same time. Also, the smoke can get pretty thick, which means my valve seals would have to be pretty shot to blow that much smoke.
I figure I could replace the heads, but am skeptical that the problem is something else. So I have been kicking around the idea of just grabbing a 290/350 sbc from Jegs or summit, but I am also worried that it might be some easy fix that I am missing.
Engine ran beautiful until the fuel dumping issue and I would appreciate any suggestions regarding other things I can check and possible solutions. Especially since Cherry's Jubilee is in a few weeks!
Thanks for the help! This site is awesome because of all the information provided by its members.