Need ya'lls opinions on SBC heads
If they are the Patriot Freedom heads 2168 with the 185cc runners they should work real well with your 355 motor. The 64cc chambers with the flat top pistons will have about 10:1 compression which is good for aluminum. I would be worried about detonation with the iron heads especially after being milled. Be sure to have the matching valve springs for your camshaft installed on the new heads. If you install new lifters get some 30w Royal Purple break-in oil. Do the cam break-in procedure for about 20-30 minutes at 2500 RPMs. When changing oil after break-in use 10w30 or 10w40 oil with the ZDDP additive and a good filter. When time come to build the 400 motor you will need a set of heads with about 210-215 intake runners.
Last edited by cdminter59; 11-01-2012 at 10:36 PM.