Overheating when driving and gas tank building up pressure

[urmyboyblue]

Did you check fan rotation to see if it is blowing or sucking?

I happen to read a little about the FI Fuel command center. It is capable of feeding 800HP. At road speed, you are making 100 or less which means a lot of fuel is bypassing back to the tank. That is your source of heat in the fuel. Unless you can turn the pump down with an electronic controller, you may have to go to a smaller pump. Also- does the return return the fuel under the fuel level or just allow it drain back into the tank. If it just empties into the top, it will cause aeration and pump up the tank more than just heat will. You need to return fuel under the fuel level.

[Adam1966C10]

The fan is on the engine side and feels like it is pulling the air properly. That is probably why it does not get hot while stopped I guess. Only heats up at higher speeds.

I will move the vent so it it attached to the tank in another location.

I also will adjust the fuel command center as suggested by Fitech here.
http://fitechefi.com/fitech-uploads/...tionFiTech.pdf

Hopefully this will take care of the over pressure issue.

Thanks for your help.

[Raked 64]

I fought a similar problem on my 64.
Long story, here are the cliff notes:
Engine ran hot at highway speeds and sometimes in traffic
tried several electric fans and even installed a large fixed blade fan
Installed an Edelbrock aluminum water pump ( made it worse)

I believe we finally found my issue. (waiting for the 100 degree heat to be sure)

I run March pulleys and the water pump speed was too fast. (hence the reason the Edelbrock high efficient pump made it worse)

We ran a calculation and slowed down the water pump. I have been running 190 since. I hope it stays there...

Won't take long to do a little measuring and check your setup

[number9]

Had the same issue on a truck I bought in Arizona and drove back home, would only get hot at freeway speeds. The timing was waaaay too far advanced. Stopped by a O'Reilley's store and bought a cheap timing light and distributor wrench. Reset the timing and adjusted the carb and the problem went away, sometimes it is something very simple. By the way it had one of those shiney chrome aftermarket radiators in it that I took to my buddies radiator shop when I got back, flowed like crap. Put in a oem brass style radiator, much nicer. My truck never runs over 190 now, 230 may be alright but it should never run that hot.