Basically Im concerned about performance. I have a zz4 long block I could use but I was hoping for more from a 406. Wasn’t that impressed with the zz4. So here is what I have for the 406 build. Heads? I have a nice set of 461's with 64cc chambers, 2.02/1.60 in good shape with hardened seats and drilled for 400 steam holes with screw in studs. Not the 461X But Im concerned that they may not allow enough air in and out and that with the 64 cc chamber I may be pushing my CR for 93 octane. I would like to use the parts I have simply because of economics but if its not going to perform then I need to make changes. I could spring for a set of heads…Not vortec please. Something aftermarket. Heres a list of what I have 406 Bore:4.125 12.5 cc dish piston 5.7 eagle rods with apr blots Stock crank Dual-plane performer intake 750 double pumper Double timing chain and gears Rotating assembly balanced. Block has not been decked Summit Racing Part Number:CCA-CL12-239-3 Hydraulic flat tappet Duration 262/270 Lobe separation: 111 deg. RPM Range:1,300-5,600 Intake Valve Lift 0.462 in. Exhaust Valve Lift 0.480 in. But I have a few sets of 1.6 / 1.5 roller rockers if needed. Grind Number:CS X4 262H-11 Im curious about the torque and horsepower with this set up and the performance I can expect. Built power glide 3:36 10 bolt 1966 Chevelle Thanks.