Another Head Thread...

I'm running 12.10 113 mph through the same exhaust manifold and slightly modified stock intake. This is a 410 so they don't compare as far as that goes, but don't discount the exhaust manifolds. IIRC stock eddy heads are worth about 15/20 cfm over a stock x head. However the eddy heads present some issues. It's hit or miss that the drivers side exhaust manifold will hit the head where it turns back towards the block. If you buy a header flange and get longer studs and extra gaskets. It will space it out enough to clear. Also alternator fitment can be a pain. You may have to modify the adjusting arm to bring the alt up so it doesn't hit the head. Then a longer belt. My cam is about .557 lift. You also need different head bolt/stud kit with the eddy head. 3.73 gear would be good. What you have for a center section can dicteate what choices you have for gear. The intake is your restriction. 750cfm would be the minimum carb. Back when these cars were new, one of the easiest performance gain was to put the bigger AVS on it.