I'm building up a 400 low deck block for my '65 Dodge Coronet. It's a new old stock block that I found with stock flat-top pistons, crank, rods, etc.. I plan on using a forged 383 crank in place of the cast one that's in it now (As soon as I can find one that is!). I'm using an Edelbrock STR-15 crossram manifold and will be using a set of 625 cfm Carter AFB's. Using 1 7/8" headers and a Lunati bracket master II cam w/ advertised Duration (Int/Exh): 292/292 Gross Valve Lift (Int/Exh): .480/.480, RPM Range: 2500-6000. I just bought a set of 915 HP closed chamber heads with the larger 1.74" exhaust valves. My question is this: has anybody used a set of these 915 heads on one of these low compression motors? Does anybody know what compression this is going to give me using the stock flat-tops? Any advice on how to make this combo work for me would really be appreciated? This is going to be a street driven car.