First time swapping edelbrock aluminum for 915 cast iron heads.

I’ll try to answer some of your questions everyone. I believe my original 915 heads chambers if they weren’t milled down are at about 78cc and the previous engine builder about 15 yrs ago said the compression with the 915’s was at about 9.8 to 1. The cam is 284 duration 484 lift and it’s in a 4 speed. The motor has about 10,000 miles on it after about 15yrs. It still runs great at about 30-40 psi oil pressure hot at idle. I had the edelbrock rpm performers freshened up by a machine shop I trust. They say they are bolt on but I never trust that statement. The heads were milled slightly to be true and mildly ported. Originally they had 75cc chambers but my guy at the machine shop said after milling they are down to about 72cc. So assuming the gasket is a similar thickness to what was pulled off I’m thinking I’ll come in with slightly higher compression about 10.2 to 1. The gaskets I purchased are cometics .020 thickness. I’m hoping I can get away with running 93 with no probs. I’m hoping for about a 40 horsepower gain over the old 915’s. I’m a little concerned about the comment on needing different pushrods? I thought all I would have to do was swap over my Harland sharps off my 915’s put everything back and I would be good to go. What does everyone think? I’m interested for input.