I picked up another guy's shortblock. It's a 1990 350 2 bolt block with a scat two piece 383 crank (3.75"). He claimed it was balanced, and there are some hole drilled in the crank throws, but all I got in the deal was a pioneer balancer. I figure it's the right one, because it's got a big weight screwed onto the back it it. What flywheel can I run with this. The previous one was from my forged crank 327, and has a weight (a lug nut actually) welded onto it. Do I just remove the lug nut, or can I buy an ext balanced flywheel?
Mike  

You're gonna need to get a 383 specific flywheel and then have it balanced to the crank and balancer by a machine shop. That's the best way to do it.  

dusterdood:
I picked up another guy's shortblock. It's a 1990 350 2 bolt block with a scat two piece 383 crank (3.75"). He claimed it was balanced, and there are some hole drilled in the crank throws, but all I got in the deal was a pioneer balancer. I figure it's the right one, because it's got a big weight screwed onto the back it it. What flywheel can I run with this. The previous one was from my forged crank 327, and has a weight (a lug nut actually) welded onto it. Do I just remove the lug nut, or can I buy an ext balanced flywheel?
Mike

I did not know you gwt a383 flywheel ,normally it is a350 or 400 flywheel
J Smit  

A 383 stroker needs to be externially balanced just like the 400. Therefore you could use a standard 400 or a 383 specific flywheel. But not a 350 flywheel; because of the lack of balancing weights welded to the flywheel. If you are not going to run it past 6000 rpm you should be fine without the added cost of balancing the whole rotating assembly.  

When you balance a 383 as with mine that's internally balanced it requires a stock wieght balancer and stock type flywheel. If it's balanced as the seller stated and the balancer belong's on that crank go to auto zone and put a heavy duty 350 flywheel on it.  

Find out if it's ext or int balanced if it's ext use a 400 flywheel & balancer if it's int use 350 flywheel & balancer.