Getting conflicting search results for this. What flexplate do I need for 1991 305/700r4/starter - all stock

1 or 2 piece rear seal - I know this is 1 piece

153/168 tooth count - ?

Internal/External engine Balance - I thought all 86+ small blocks were internally balanced (except the 400) so not sure why summit sells an externally balanced flexplate for a 305/350??

Weighted/non-weighted - ? Does it need the little bat-wing weight on it?

Converter bolt pattern? 10.75 or 11.5?

Researching my dissertation was easier...thanks for the help.

 

All V8 third gens were 153 tooth.

The weight is part of the internal balance of all 86-up SBC. There is no 86-up 400.

 

Thanks for the clarification.

So I need:
1 piece rear main seal
153 Tooth
Internal Engine balance

Any idea on the bolt pattern/size?

 

Found out it's 10.75 inch bolt pattern.

Still not sure if that weight on the flexplate needs to be there. I found some flexplates online that meet all the criteria, but don't have the weight bolted on it.

 

For 1 pce RMS engines that have been custom balanced

The info on the Summit site is confusing as they erroneously call any flexplate with a weight on it " external " balance

Sofa's comment below tells it as it is

https://www.thirdgen.org/forums/post...243-post6.html

 

Then, "no you didn't."

There may be aftermarket neutral balance flexplates for 86-up crank bolt pattern, but those aren't working with a stock 86-up SBC.

The "imbalance" weight stays the same, whether 86 Z28 engine or 2002 5.7L GMC van. The balance work is done internally to the crank.

 

Thanks Vetteoz - Sofa's comment you posted clears up all the confusion. Like you said, the descriptions on Jegs/Summit are very confusing - calling these things externally balanced - which refers to the external weight attached, not the engine balance.

Anyway, I ended up getting this: http://www.jegs.com/i/JEGS+Performan...01073/10002/-1

Hope this thread helps anyone else looking for a flywheel for 86+ 305 in the future.