Runs hot on the highway

[T-Boy's GW]

My AMC 360 rebuild with the timing chain, AL rad, and water pump upgrade from BJ’s … I’m still having temp problems… I can putt around town all day and it runs cool (180 – 200) but as soon as I get up to highway speeds 55 to 65 (still in break-in) the temp will bolt up to 250 – 260 and hang until I slow down and then it drops just as fast to normal. I replaced the thermostat once with no change.

[chief1ton]

Have you checked your timing curve. and total advance? on the freeway your running at or close to full advance. around town your not. if your total advance is running to high it will cause it to heat up.

[Stuka]

Sounds like a timing issue or a carb issue. You may be running way lean off idle which will cause high temps as well.

[T-Boy's GW]

Thanks, I'll work on that this weekend.

[T-Boy's GW]

I have a HEI ignition, to I use the manifold vac or timed vac for the advance?

[T-Boy's GW]

Also, I'd like to have a tac gauge. Anyone have one they like?

[Stuka]

I would suggest ported (timed) vacuum, unless of course you plan on road racing it