mechanical 440

[joe connor]

I just dropped a mechanical 440 pushing about 625hp with th edelbrock dual quad carb system into my 70 rt challenger.Heres my problem.I fueled the car with 10 gallons of sunoco gold plus 3 gallons of c12 fuel. When the engine is cool,She makes tons of power when i buzz it.But once you get to drivin bout 20 minutes and try to buzz her,she falls on her face.Then when i check both 600 cfm carbs,you cant touch thme without burnin your hand.Does the c12 fuel make it run too hot and should i just use octane boost when driving other than the strip. Please help as this motor cost me way too much to cook it . THX

[Doug Wilson]

Joe - forgive my ignorance, but what is c12??

[joe connor]

c12 is a racing fuel

[rumblefish360]

I would guess that would be the problem. Sounds weird though.
If it didnt do it before, that would be the problem.

[Doug Wilson]

Maybe isolate the carbs by using a plastic or wood spacer under them. It shoouldn't take very thick ones - maybe 1/2 inch.

Also, the c12 - race gas - should not make the car run hot. If it's basically a high octane mix, it should help the engine run cooler. You could try backing your timing off maybe 5 degrees.

What kind of temp is the coolant running when it's "hot"? Maybe it's a fuel line routing problem or a cooling system hex.