I think I have an out of balance problem. I pulled the 6 out of my sons 75 Mav and put in a good running mid 70’s 302. I had a good used flex plate but I used the torque converter from the 6cyl and a late model harmonic balancer. The motor runs well but feels very out of balance. To the point where it shakes up and down. Any ideas???
You can't use a late model damper since it will be 50oz imbalance .... both the flexplate and damper need to be 28oz imbalance for an 70's 302 ..
yep, what dan said. 28 oz for the 70.better get the right balancer on before ir screws up the crank and anything else.
WOW, thanks for the quick help!!! I'm pretty sure that the flex plate is an early one. Is it ok to leave that converter in?
The converter for the six, assuming it is for the 250, is ok but it will act like a high stall converter when put behind the 302. It will generate slightly more heat when driving around town so adding a cooler to the one in the radiator is a good idea. Is the transmission also from the six? If so add a big (30000 lb) cooler. The C4 behind the sixes is not as stong as the V8 tranny and heat will kill it fast. A good shift kit (TransGo 40-2) will also help the tranny live a long and happy life behind the 302. Paul
I just had the trans rebuilt by Lee Miles and told them to put in a shift kit and that it was going behind a 302. It works great. And I do have a trans cooler as well. They did a nice job. I guess I better find a balancer soon and a pulley.
Hey Robbie, Yeah, I'm getting the same thing from my son. I've been working on his C4 so he can take his Ranchero out to the strip. I spent some time on here talking to PaulS about what I need to do to it and it's almost complete. I just came in from working on it just a while ago. Dang it's still humid out there! Anyhow, if it works it will be my first successful auto rebuild! I'll be there Don. We went out for a test and tune last Saturday and found another issue with the belt drive. It was leaking oil pretty bad. I think that we are going to go back to a timing chain and stock style cover until we figure it out but we are going for points.
