Hot Rods ZZ4 to th400 flexplate

I have a zz4 350 sbc casting #14093638. I will be mating this to a th400 trans. My old flexplate is 168 tooth, 4.125" dia but the crank hole is too big, I need one with a 2" crank hole for 1 pc rear main. Can anyone give me a part number for the correct flexplate? I will be about 500hp and would like a good plate. Also can I use my old converter? Thank a lot.

 

Don't have part number handy, but just need flex plate for one piece rear seal crankshaft with the large diameter flexplate. Your converter should bolt to it, if it has both patterns drilled in it.
Check this one at Summit
FRA-159HD

 

Is the ZZ4 externally balanced? If that is a stock converter, 500 HP will probably require a higher stall converter.

 

according to the instructions, you probably want GM 14088761

https://www.chevrolet.com/content/d...ne-long-block-installation-guide-24502609.pdf

 

Thanks fof the reponse

It is externally balanced. I have a 355 sbc with a Howards Cam in it, 525/530 lift, 226.6234.6 dur. @ .500, /1800-5600 rpm band, AFR 195 heads, TH400 trans, and 373 rear gear. This should give me approx. 500 hp. Howards said I could run a stock converter which didn't sound right to me. I have a 2400-3000 stall that I used on a 400hp engine that I was planning on using. Does this sound like it would work? I really appreciate your input.

 

Thanks for your reply. Would the standard work for a 500hp roller cam?