Is their different sizes?? My buddy switched his out with a refit....and now can't get a starter to engage with the flywheel...he has tried mutiple starters???

uh oh, did the fly wheel get changed. I used my Jet Boat 454 as a Donor engine. Guess what, the flywheel gear was closer to the block because it was made for the starter to be mounted like a Car starter does. The fly wheel with the rear facing starter has the grear futher away from the block. Um I guess another possibility is, well, put it this way.... I don't even know if its possible or not to put a fly wheel on backwards or not. Try to see if the gear is closest to the starter.


Notice the gear offset on the flywheels of those two pictures posted.

Is he running a rear mount plate?

I think they all come in one size. But if you run a rear mounting plate, it bolts between the housing and block. So some of the bell housings will be milled down the thickness of the plate.
Ran into this problem once myself.
Gary

As stated abouve, if he is using a rear mount plate, the bellhousing has to be "cut". I ruined 2 starters finding out the hard way the differences between a "cut" and "uncut" bell housing. It is a simple fix if the engine is already out.

Can you buy them cut? Or does a machine shop have to modify it?