My project isn't a 3rd gen. F-Body, it is a 1955 Chevy 2DR post. I have a 406 SBC with 1989 TPI converted to SD. I have a Ed Wright Chip, 24# injectors, stock heads with steam holes, Comp. Cam #12-404-4, stock throttle body, new cross flow aluminum radiator with 3300 CFM electric fan & new aluminum water pump.

I've just started the engine a few times to check it out. I don't have a tack, but it won't idle below estimated 1000 RPM. It will warm up to the 160 degree thermostat and dwell there about 2-3 minutes then the temperature starts to climb and doesn't stop until the engine is shut down. All this takes place within 5-8 minutes. I haven't ran it about 210-220.

When shut down, the hoses, radiator & water pump are hot so I assume I'm getting flow through the radiator to the water pump and back.

With the thermostat removed, I have confirmed that the passages from the intake to the heads are open. Are there other passages that could be blocked?

It is running very rich and I'm not real comfortable with the timing. Would rich fuel mixture & timing contribute to this extreme heating?

Thanks for your help.

 

yes the timing will do that. A sbc 400 got a bad name early in life for no reason and many will tell you "oh a 400 you need a better cooling system" which is not true. I would guess you have bad timing or wrong rotation water pump usually some minor over looked thing like that

 

Thanks, since the post, I have confirmed the water pump rotation is correct. I haven't got back to the timing issue, but did modify the area around the electric fan to improve the amount of air pulled through the radiator.