I've been slowly working out the bugs in my 70 Runner. It's got a 440 that supposed to be mostly stock except for a 509 cam. I didn't build the car or engine-I'm just cleaning up all the messes left by the last guy. It runs hot and I've burped the system, verified (and reset) timing, replaced the fixed fan with a clutch/fan setup, installed a 180 thermostat (ran hot), pulled the thermostat and ran it (still ran hot). I pulled the 974 radiator and had it checked by the local radiator shop. They said it had recently been recored and flowed just fine. The water pump is fine. I'm guessing that the 26" 2 core 974 radiator (from a 340 6 pak E body) is just too small for the 440??? I figured that since it was a 26" radiator it would cool ok, but I guess not???? any guidance? Thanks
The 340-6 pack radiator (2998974) is a 26" radiator - only thing you might do is have it re-cored with 3 rows vs. 2. Nothing wider than a 26" came in E or B-Bodies. Also, coolant passages in the motor could have a bunch of mud accumulated. I had a '78 Super Coupe 360 that ran hot all the time. I pulled the radiator & had it boiled & inspected, & that did not solve the problem. We pulled the motor to paint it & replaced all the freeze plugs. First one we removed revealed a bunch of sediment (mud) that was all settled in. We took them all out & took a garden hose & really flushed out everything - a LOT of crap came out of the passages! New freeze plugs, got it all painted & detailed, reinstalled the engine & it ran nice & cool! Good luck.
