What would I be looking for if I was to order a replacement flexplate for my 85 Z28 equipped with a 305 and 700r4?

Slso, what is everyone's opinion on the lightweight flexplates? Doesn't look like they have a whole lot of meat to them...

 

Well what your would be looking for is just a standard flex plate for use with a 2 piece rear main seal (unless the motors been replaced with a newer one) and with the smaller tooth count i believe 153? Light wheel flex plates rea great in my oppinion as ther reduce a good amount of weight helping acceleration faster revs ect. If there strong enough for day to day street use? That would be someting to ask the manufacturer about because something like that may vary frombrand to brand depending on their perpouse and quality. I would say tmany of them would be fine for street use but again ide check with the manufacturer

 

Correct, 2-piece rear main seal, 153-tooth (12-3/4").

Makes more sense to get a smaller torque converter than it does to get a lightweight flexplate. An SFI piece will take more abuse than a standard replacement, but it probably isn't necessary. A plain old Pioneer replacement will do for most applications.

 

OK. Last question.

How do I know whether I need an externally or internally balanced flexplate?

 

You need the internally balanced flywheel.

 

OK I just ordered a 153 tooth PRW flexplate for a 2 piece internally balanced engine made out of chromoly.

But It's advertised as SFI approved and says 0.35" thicker than stock. Doon't I need tto worry about using a different spacer now?

 

Bump

 

Well it depends in what way is it thicker. Ive heard of some that were machined thicker to compensate for the use of engine plates or it could just be thicker in a different way to be stronger yet bolt in like a factory piece. You really have to call the manufacturer for something like that.