My 383 will be ready to be picked up this afternoon from the machine shop. (After going through quite a lot of grief)

An interesting note on the balancing: This is a one pice rear main seal block. AFAIK, all one piece seal blocks were external balance at the rear, internal at the front.

My piston rod combo turned out to be pretty light. He was able to completely internal balance the engine. He simply removed the counter weight from the flex plate by drilling out the spot welds. This gives me the benefit simpler flywheel/flexplate changes down the road as I see it - plus, I can now use my universal fit crappy plastic torque converter cover without that weight whapping it on every revolution!

Al,
What a lot of people dont realize is that all the earlier 350's were also "external" balance, depending on how you want to define "external". If you look at the flywheel flange on the 2 pc cranks, the way it is shaped is for balance purposes. That is the reason that when the went to the one pc cranks, they had to put a weight on the flywheel.

Thanks for that info, Bill. Something I'd never considered. Did the 327 and smaller cranks have round flanges?

Right Bill,

Yes, the little "fan" on the edge of the flywheel ends of all the cranks from 327 on up were just for that purpose.

Only the the early 265, 283 and 302 didn't have them b/c they were round except for the medium journal 302 having a notch taken out of it..

Don't know about the offbeat 262, 267 and 307 motors cranks though??

pdq67

actually, taking that weight off the flexplate will cause more problems down the road if you need to swap it out- the one piece seal engines have a different bolt pattern than the old stuff, and all the flywheels and flexplates made for them have that weight on it. i think it should have been balanced with that weight on it, personally.

hey bpos, whats your bob weight on that thing? just curious.

That's what I thought, Derrik. But the more I think about it - if you want to re-balance after a flywheel change, what is easier? Removing the weight from the new flywheel and neutral balancing it as a stand alone piece - or - having the recip assembly re-balanced with the new flywheel attached?
I suppose another option would be to stab the new FW that has the weight on it and hope it's close enough.

I'm interested in opinions, although what's done is done.

Originally posted by 68rs406:
hey bpos, whats your bob weight on that thing? just curious. Just got off of the phone with the machinist. Bob weight was 1683.

Al,
That is a very light BobWeight. To add to Derricks post...it is always better not to have weights on the flywheel or damper if possible. It is a lot easier on main bearings, especially # 2 & 4, thats why most race engines are internally balanced. On most street applications it probably does not matter much. It is no big deal to balance a flywheel if it ever needs to be replaced.

that is a nice light bob weight, it should spin nicely. my 406 is 1730, which is also fairly light really. thanks graemlins/thumbsup.gif