Does anyone know if the aftermarket (TCI, Summit, B&M etc) and GM 168 tooth flexplates beginning with the 1986 one piece rear seal for the SBC all have the same counter weight? ie are they a direct swap with a damaged '86 flexplate or does the rotating assembly need to be re balanced?

Thanks
Roy

 

I'm fairly certain the cars use a small 153 tooth flexplate or do you have a custom thing going on?

 

Thanks TTOP, have not counted teeth yet but will prior to any ordering of a new one. Just need to know if the counter weights on the flexplates were engine specific or would balance any one piece rear seal crank.

Roy

 

All stock 1-pc RMS for 305/350 cranks have the same balance.

Aftermarket ones are a different matter... all bets are off, if they say anything other than "stock".

Same for aftermarket flex plates and such... if they say "stock", then they should be OK. If they say anything else, ... ,, ..... caveat emptor.

 

I've never had a problem using an 86-up SBC GM flexplate or flywheel on another 86-up SBC.

If your starter bolts are perpendicular, look for 153 tooth.
If your starter bolts are diagonal from each other, look for 168 tooth.

 

Thanks to all for responding with good info. 153 teeth and I can use an '86 and up RMS flexplate. Next test question. Is it possible to remove the flexplate w/o separating the trans from the engine. I've always R & R engine and trans together from the car and then separated them. It seems there was at least a half inch of travel in and out/fore and aft on the trans shaft once the TQ converter is fully seated. Just enough room to slide the flexplate down and out between the crank and TQ converter? Any thoughts on this? tracking down a problem that may require a flexplate swap. Thanks again
Roy

 

No it is not possible. They must be separated at least far enough to get a tool up in there and all such as that. 2" is usually enough but it depends on your wrench.

My usual technique for many many years has been to take out 2 of the lower bolts and put longer ones in their place, maybe 5 - 6" long; support the trans on a piece of plywood or the like under the pan; and slide it rearward enough to gain access.

 

Thanks Sofakingdom, great gouge/tip on the 5 or 6" bolts , bellhousing to block I'm guessing
to slide the trans back and keep it all aligned and supported with a jack. No prob, pain in the backside, but not pulling the engine. My original thought was a flat wrench with an internal ratchet end and rotating the crank to orient the bolt being remover/installed to the bottom. If I remember correctly the bolts securing the plate to the crank are very close to the crank/snout flange and a socket barely fits to remove the bolt!
Thanks again for the tip
Roy