I have a 92 k1500 with a 350. I blew a head gasket two weeks ago and replaced that. Less than 24 hours after getting it put back together it started running bad again (shaking, loss of power, slight smoke before i shut it off). I tore it apart again and had blown another head gasket. I replaced the gaskets for the second time thinking maybe the replacement gasket was bad when i bought it. I have had it put back together now for about 3 days and at first it was running alright but now its lacking ALOT of power on acceleration, can barely make it up a small hill going 30. The oil pressure when i start it will be around 45 but as i drive it the pressure will end up around 15-30. It doesn't seem to be gaining or losing any level of oil and the antifreeze level seems to be staying about the same. I don't smell anything out of the ordinary in the exhaust gases. I have no idea whats going on and need to figure it out ASAP. Any help is reeeallly apreciated!!

 

Did you have the heads checked for warpage when you had them off? Valves adjusted properly? Make sure intake is sealed? Timing set correctly?

 

What does the temp hand say ? Like said check timing 0 degree.
Sounds like a clogged cat. Did you get all wires back especially the grounds at t stat.
Like said^^ may have valves to tight. Does it back fire any?