is the stock flexplate used a 168 tooth, 11.5" bolt pattern or 153 tooth 10.75" bolt pattern? im thinking its the larger one

 

Easiest way to tell is by looking at the starter, or the mounting holes on the block. Starters that mount with the holes straight across use the 153 tooth plate, diagonal holes uses the 168 tooth.

 

Stock would be the 153 tooth....

 

i think i understand, the bolt holes are kind of offset. crap, the only way i can find out then is to call someone who has info on the 383 im buying

summit's tech help said i can use either one depending on the starter, and said my starter uses the straight bolts and to use a 153 tooth. thanks guys

 

When you get the 383 find out if it is internally or externally balanced, as the flex plate will be balanced differently. 383 strokers can be built both ways, if a crank from a 402 is used it will need external balance, if a new crank is used it could be either way.

 

Plus, some blocks came drilled to use both styles of starter. That may be what the Summit tech was referring to when he said you could use either one.

 

i think thats what he was trying to tell me. i started doing the wiring repairs today and noticed my starter case was broken, im assuming from when the 305 went boom, so im going to be getting a new one soon. autozone and advance auto always have some sort of online special that ends up saving me a bunch of money, and saves shipping for store pick up. i do know that the 383 is external balance and found the correct balancer and flexplate to use