sounds like you have multiple problems. first off if you have vac line problems and have had them for some time you very well could have been running it lean and burnt out your rings. also without you knowing your vac leaks very well could have gotten worse now causing it to run to lean. anytime that your having engine problems and you know yo have vac leaks then thats the first thing you need to fix. once you think you might have gotten them all start the engine, let it idle, and spray brake cleaner over every line, vac power items, ext. the brake cleaner will make the engine idle up noticeably with so much as a pin hole leak. vac line also have a tendency to stretch due to heat. use zip ties at every vac line connection to help ensure a tight seal. using brake cleaner along the intake and intake gaskets will also reveal if you have a cracked manifold and/or blown intake gaskets.
did you by chance check the oil and coolant to ensure there is no mixing of the 2 and also for fuel in the oil?
fuel pressure, did you check to make sure you have enough fuel pressure. its been some time since i have worked on carbureted engines but i think you want something like 8-13psi. check the pubs or you local chevy dealer to confirm that.
easy way to check for clogged cats is drop the exhaust and start it up. other than sounding bad and loud if it runs any better then you know it was your cats.
did you check your timing to make sure it still has a correct tune?
does it have a hei ignition? if so bench test the spark modulator to ensure proper function.
does it have any knocking and/or ticking sounds and if so from which location?
thats just some things i would have checked off the top of my head.
did you by chance check the oil and coolant to ensure there is no mixing of the 2 and also for fuel in the oil?
fuel pressure, did you check to make sure you have enough fuel pressure. its been some time since i have worked on carbureted engines but i think you want something like 8-13psi. check the pubs or you local chevy dealer to confirm that.
easy way to check for clogged cats is drop the exhaust and start it up. other than sounding bad and loud if it runs any better then you know it was your cats.
did you check your timing to make sure it still has a correct tune?
does it have a hei ignition? if so bench test the spark modulator to ensure proper function.
does it have any knocking and/or ticking sounds and if so from which location?
thats just some things i would have checked off the top of my head.
