The guy who really knows this is JohnRR. Maybe a PM to him is in order.

IMHO by the time you get done messing around trying to make this or that piston work, you will be within spitting di$tance of a custom forged piston which will be exactly what you need. Trying to find a new set of old TRW slugs is a hassle, buying a set of Speed Pros will cost more than you think. Either choice will be incredibly heavy, because the OEM pistons were heavy. The TRW or Speed Pro pistons were built to replace stock pistons. You should be able to save over 100 grams per piston with a custom forged piston from one of the companies I mentioned in my last post.

Really check your options before buying a piston.

R.