Well it looks like I got my hands on a 454 block for me for Christmas, ho ho, but I got to get mama's 396 humming before I can start my buildup. I have the 3969854 block which shows 396/402, 69-72 use. The block says hi perf pass bossed into the block. I calipered it out to 4.11" across the top of the cylinders. Since this is only .007" above the std 396 bore, I can only assume I"m measuring the wear and its a std bore 396. I want to take it to the 375hp version. Can you tell me what the cam profile was on those, and compression. Was there a steel crank in those? And last but not least I have the 3999241 heads to work with. Will they work, or will 2.19's and a little bowl blending in order? Street car and b-day present for the wife. Thanks guys.