HELP with Flywheel differences??????

[Griffin]

I'm swapping from a 3 speed to a SM465 and need some help. I have the flywheel that came from the donor truck but 400's and 350's were available in the 1976 donor truck and i don't know which one came in it. I know the 400's are externally balanced and the 350's are internally balanced. I know there is a difference but how do you tell? is there a extra weight like a flexplate, dirrerent size, etc... Will the flywheel from the 3 speed work?

[70rs/ss]

If it is going on the same motor the 3-speed came from then yes the flywheel from the 3-speed will work for the 4-speed. The 400 and 454's have an extra weight on the motor side of the flywheel, don't use it on a 350 your fillins' will fall out!!

[Griffin]

Thanks! I figured it would some kind of extra weight similar to the flewplates but wasn't sure. I had a buddy that used a 400 flywheel on a 350 and added a couple or new drain holes to the block so i wanted to be sure. Thanks again.