What are the best heads I can get for a 305 TPI engine without having to change my intake. What kind of power increases would I have from 210 HP (stock heads). I'd prefer lightweight aluminum heads too, but cast iron will do. I'm trying to figure out what I can do best without having to replace the TPI system, intake, do any drilling.

 

The problem is, you really need to do all 3 to get the full benefits. The power of the engine will be limited by the "weakest link". On a stock TPI engine the intake, heads and cam are all pretty well matched and changing just one thing will be limited by the other "stock" parts.

If you were to go to a slightly longer duration cam you will notice a difference. But you don't go too far (duration or lift) without fixing the heads and intake or you end up with a cam that starts killing low end torque but your intake and heads won't flow enough for the top end (like the cam wants to) and end up slower overall (lost bottom end TQ and no gain in top end HP).

Heads (alone) will just be chocked by the intake itself. At lower rpms it will probably have more TQ since the intake can support additional flow there, but as the rpms increase the intake will choke it and limit the high end rpm potential of the heads.

Changing intake (alone) generally helps both in low end TQ and the top end. It is probably why most guys change the intake first when they start to modify their motors.

I toiled over this same dilema over the last 3 years and I eventually decided to wait until I could do all 3 simulataneously and match them to each other. I now have all the parts and will install a new intake (Miniram), heads and cam this spring.

 

if you are willing to change intakes id go with alluminum vortex but world products sells a 305 torque head that i dont think you have to change intake with...