383/TH350 flexplate question

[Chevy Tom]

I’m building a 383 SBC to replace the original 305 in my c10. The block is a 87-95 1 piece rear main seal roller block. I plan on using the Th350 that is in the truck, which will be built up. I will be using a summit brand 2500 stall converter. The engine is internal balance. What flexplate should I use? Will I need a special one? Thank you

 

[Frankenchevy]

I believe, unless yours is custom, that engine is internal and external balance. That is what I think my 1-piece RMS Vortec is. I used a Hays SFI flex plate. If you go to summit and search for an 87 c10 flex plate, you should be in business.

 

[Chevy Tom]

the engine is custom, internal balance. Im running a neutral balance balancer and need a neutral balance flexplate. Im assuming a stock 1 piece flexplate will work. Just want to make sure.