Hallo guys,
one of the former owners of my car has put an old 305-engine ( build about 1978 I think ) into my IROC. Now I want to install a 350 ( build 1988 ). Whats about the flexplate. I read the archives, and I know that I definitely need a new one. But do I need one with 153 or 168 tooth and can I use my old starter ?
Thanks, Uwe

 

if you are talking about an automatic flexplate, you can use either. which is in there now, and why do you need a new one?

 

I think the 1978-engine has a 2-piece seal and the 1988-engine has a 1-piece seal, therefore the flexplates ( it´s a TH700 ) won´t fit ? ( Should have another bolt-pattern ? )
Thanks, Uwe

 

as far as i know, 1987+ is a 153 tooth flex, while anything before 1987 is a 168 tooth

 

Either size is available for either crankshaft type.

The easiest thing to do, is to determine what you have now, and get the same size one to put on the other motor. Look at the starter; if the 2 bolts are directly next to each other, then it's a 12¾" (153-tooth) flex plate; if the bolts are staggered, such that the one nearer the crank is about 1½" farther toward teh front of the motor, then you have a 14" (168-tooth). Just get a 1-piece design one to match the size you have now.