Horse Power Potential of Cylinder Heads

Tech857 said
I may end up swapping to a manual trans at some point. For now I'm going to stick with the 727. I was thinking of putting the engine together with my stock iron heads just to have it running sooner. I just don't want to choke it out. The stock heads have 42k miles so they could be cleaned up and used as is. There was nothing wrong with them. But as soon as your start throwing valve springs and parts at them it makes more sense get aftermarket heads. I get a really nice discount on anything from Mopar so anything in there catalog is on the table. But I don't really know how much flow I really need for an engine that is street torque build that will not see more than 6k. I don't want to run a 3500 stall converter and have no low end. I drive this everyday in the summer.

A couple thoughts - there are no camshafts that would not require some sort of modification to the heads: spring seats cut, guides cut, etc. They may have exhaust rotators too which would have to go - and the exh valves are different in regard to where the lock grooves are placed on those so it means new exh valves. Plus - the stock work is not really that great. If you want to screw on bone stock heads and install a bone stock cam, you certainly can do so. But I don't see it doing much more than giving a bit more torque off idle, and not having much mid range (I consider 2500-4500 as "mid range" rpm). It will be it's own rev control so I'd say probably 4500-ish will be max rpm. Additionally - there's not much from Mopar Performance that will not require a lot of cash to get running. Your cheapest way out would be the Engine Quest Magnum heads. In stock form they have closed chambers, have the LA intake pattern, are cheap, can run the factory Magnum rocker gear, and will flow enough air to feed a mild stroker - they will outflow any stock LA type head right out of the box. You should be able to buy them, have them assembled with a spring to work with a milder cam (around .510 lift with a 1.6 rocker), and ready to run for the same money as having the factory 360 heads set up for performance work.