hey guys,
my brother is swapping in a late 70's 355 into his 86 camaro. he pulled the old (now dead) 305 and we found a pin, about 1/4-3/8in wide (im guessing dont take that very strictly) pressed into the crank and it lines up with a hole in the flywheel. i checked my 305 that was out of a 84 Camaro and it didnt have one, but then i thought it may have been an automatic thing (only manuals may have it) but then i checked another 305 we have that was out of my 84 trans am which was a manual and it dosent have one!?? i am wondering if this is something that 1-piece rear seals have and 2-piece rear seals dont, because now that is the only diffrence i can find. we need to get his car back on the road asap so any feedback is greatly appreciated
Thanks
Joe

 

I have a 1994 1 piece rms crank that has the dowel pin, it was mated with an automatic. I didn't put one on the new 1 piece rms aftermarket crank I have, I'm using that one for a manual. I doesn't really matter. Its there to help locate the flywheel or flexplate when you install one. I just lined up the hole and bolted the flywheel on. You should be fine without one.

 

thanks so much, hopefully we can get this together now,
Thanks again
Joe

 

One-piece rear main seal flexplates & flywheels have to be indexed because they include a balance weight. Two-piece rear main seal flexplates don't have that weight, so they can go on in any orientation (except 400 SBC's, which are externally-balanced).

If you look closely at the two-piece rear main seal crank, you will see a counterweight built into it outside of the seal surface. You can't do that with a one-piece seal crank, so they put the weight on the flexplate/flywheel.

 

so does this mean that the two peice rear seal cranks need the dowel pin or do the one peice rear seal. i heard from a guy at the local napa store that one peice rear seals dont need them and that 305's didnt get them. somehow my brother has a one peice rear seal 305 with a centering dowel.
thanks
Joe

 

One-piece needs the pin. The NAPA dude is confused.

 

ok thanks five7kid, so just to make sure a two piece rear seal 355 will not need a pin?
Thanks again
Joe