[Lee]

Originally Posted by grd777

when i tried to set it on the specs .i did not run properly ,that's why i mention that i have a mild cam and my have to adjust

Details, man! WHERE did you have to set the timing?

I have a low CR motor with a mild cam, and my timing is quite normal.

[ccie3611]

For what its worth here is my 455 overheating story

I restored my 72TA, everything new in the engine, got a stroker kit from butler, bored .30 over. New vales, pistons, rods, street cam XR276HR, new water pump, radiator, fresh rebuilt 7042273 carb the works! And of course it ran hot, about 210 to 220. I tried EVERYTHING, every trick I could find on this forum and elsewhere to cool it down, most adjustments only slowed how long it took to go over 210.
What finally fixed the problem was re-jetting the carb, it was too lean with the stock jets. I added an o2 sensor to the exhaust and I could see it was obviously too lean. I put in .072 main jets with .39 rods, also replace the secondaries with AX rods. Changing the jetting made a big difference, it stopped the temp at about 195, and most important it stopped that endless climb up! I wanted to bring it down more so I researched the fan and pully (the only thing I had not replaced as I thought they were stock), I found that I had the wrong fan and the wrong pulley (both too small). I got a 485397 pulley and a 3991431 fan (correct for a 72TA) and that did the trick! Btw that pulley is hard to find!

[grd777]

Originally Posted by ccie3611

For what its worth here is my 455 overheating story

I restored my 72TA, everything new in the engine, got a stroker kit from butler, bored .30 over. New vales, pistons, rods, street cam XR276HR, new water pump, radiator, fresh rebuilt 7042273 carb the works! And of course it ran hot, about 210 to 220. I tried EVERYTHING, every trick I could find on this forum and elsewhere to cool it down, most adjustments only slowed how long it took to go over 210.
What finally fixed the problem was re-jetting the carb, it was too lean with the stock jets. I added an o2 sensor to the exhaust and I could see it was obviously too lean. I put in .072 main jets with .39 rods, also replace the secondaries with AX rods. Changing the jetting made a big difference, it stopped the temp at about 195, and most important it stopped that endless climb up! I wanted to bring it down more so I researched the fan and pully (the only thing I had not replaced as I thought they were stock), I found that I had the wrong fan and the wrong pulley (both too small). I got a 485397 pulley and a 3991431 fan (correct for a 72TA) and that did the trick! Btw that pulley is hard to find!

wow this is what i was thinking is the problem . my car is getting painted now but this is the first thing i will be working on
thank you for this info

[Formulabruce]

Alcohol in fuel really makes our Pontiac beg to run richer to run right and run cooler.