I bought a motor from an engine shop with full 5 year/50,000 mile warrenty. 4-bolt main 383 came with XR264HR cam, 1.6 roller tip rockers, on 'profressionally ported' and cleaned up 193 heads. Combo runs well with plenty of torque in my 91Z28 TPI.

I am pulling this motor and dumping it into my miniram 91GTA.. hopefully it will be a good combination.

Here is my dilema; I have a nice set of 'home ported' 113 aluminum heads. So should I put them on now while the engine is out? Will I see that much gain, if anything? If I do change the heads, are they an exact replacement (direct bolt in), or do I have to measure rod length, etc.

 

IDK about the bolts, since you're supposed to use washers under the head bolts on aluminum heads. But IIRC, the 193s are swirl-ports. If so, the power improvement should be dramatic! Unless the port job on the aluminum heads made them worse.