The Stovebolt Site Forums The Shop Area Engine Shop Removing Headers from 230?

I purchased a 65 C-10 Fleetside with a 230 in August. The engine is mostly stock and rebuilt approx. 30K miles ago. Headers were installed in the late 90's. The engine runs good when cold, bad when it heats up. I understand that the exaust manifold should heat the intake manifold. After driving for 10-15 minutes the intake manifold is still cold. I replaced the carb with a rebuilt with no change. Compression is OK for all cylinders. I don't want to remove the headers as someone did a good job installing the dual exaust. Any advice?

Does it have a phenolic block under the carb? Sounds like the heat is the problem. Chevy sixies are notorously cold natured and the heated intake was used to overcome this. The headers have likely done away with the heat riser valve(?) so that is something you might check out. Exactly what do you mean when you say "bad when it heats up? Does it have the correct carb and carb gasket?

Runs good cold but bad when it warms up? Sounds like a choke problem. Warm 'er up and pull the air cleaner and look at that butterfly that is just under the air cleaner - is it all the way open? It should be. If not, it's just a matter of an adjustment or maybe it's stuck and needs freeing up.

I think you are correct running cold,,,look at a hot water block for under the carb..We used to block off the heat to the intake back in the day to get more noise from the dual ex,s,,, work good but preformance and milage suffered...doc

The carb seems to overload with fuel and misses bad. I have the original exaust manifold and there is a butterfly valve connected to heat springs built into the top of the manifold where it should connect to the intake. It all looks like cast iron.

Purchased a rebuilt carb from LMC, only one I could find to fit that engine. It matched the one I replaced. The choke works fine and is open fully when pushed in.

The heater hoses and radiator hoses are on the other side of the engine.

Thanks for your input. Yesterday I removed the headers and installed the original exaust manifold and had a muffler shop fabricate a connection to one of the mufflers. Amazing...the engine runs great! Guess those GM engineers had it all figured out.