LA block running magnum heads

I hear what you mean, same reason I couldn't go with aftermarket heads with my build. In that case I would recommend looking in the FABO classifieds for someone selling stock Magnums in good shape. The only way to check if JY ones are cracked is to pull them and have them cleaned and looked at with a magnifying lens or magnafluxed by your machine shop which costs money. Also most machine shops should be able to re-drill the intake bolt holes, not sure how much it costs.

Do you expect to drive your car in colder weather? If not you could just get an Edelbrock Air-Gap intake for Magnums. And/or get one of the old factory air cleaners with the hot-air valve.

FWIW my 360 has brutal torque as it is since the cam is a bit small for the cubes/compression, and I put a little over $2000 in it. For basically the same amount of money if you instead put in a good mid-range single-pattern cam (Comp 270H for example) and port the heads a bit (mine are untouched except for smoothing the chamber edges down) it would really pick up the HP in the 3000-5500 RPM range. Then run a 670-750 cfm Holley with 3.55 gears and 2500-stall converter and your car would kick some serious *** at the drag strip but be easy to drive on the street.

I'm sure some other members here can give some good advice on cam and head stuff too...