I've a spare block out of a '93 c1500. My plans are to make it a more efficient engine for my 97 Blazer.

I've recently been doing research on the 4.3, and until now I did not know there was such a diversity from the 1st to 3rd gen engines, or even between themselves. I have figured out a few modifications that may need to be done, and as time progresses other little things that will need to be changed out, but right now my main concern is the crankshaft...

On a few '95 model special vins and '96+ the crankshafts were fitted with a reluctor wheel for the OBDII crank pos sensor, giving the snout a machine of 0.100" more than it's predecessors, which is a good bit as far as an engine. I'm wondering if anyone knows if this clearance would be an issue in the '93 block. I'm going to look into it some more when I can and post some feedback if no one else has yet. No sense in me starting the build without a main product.