First of all, I wouldn't make comments about heads that I have no personal knowlege of. If your going to bash Thumper heads or any ported stock head, please tell me you at least a) raced a thumper headed combo b) have had a set c) know in depth why they don't flow.
Yes, aftermarket heads are better, I knew that before I bought Thumper's heads, but budget is an issue for me. One day I will get some aftermarket heads but the only one's I would consider is AFR's. In the long run, you'll be better off saving the extra money and buying the AFR's now. Maby the aftermarket's are better on the hp:$$ ratio, maby they arn't, but this man's on a budget.
The comment, Thumper heads are still stock heads, but then again go out and get some Roush, World or other Iron head doesn't make sence to me. All iron heads start out as chunks of iron. It's what happens next in the machining that effects thier performance. It's the ports and valves, thier shape and size effects velosity and flow, and the more fuel and air can be let in the more power can be made. You want to move as much air as possible into the combustion chamber so there has be a balance between mass and velosity. Anyone who knows anything about science knows this. Yes, Thumper (mike) starts out with a stock head but changes everything about their port characteristics. If you belive that, because they started as stock heads, the air molocules are going to stop and back out, you better contact the head company and be shure that the iron ore they got didn't come from the same mine.
All I hear is how Thumper heads are just junk stock heads, and how my combo is so slow. Well, show me my s*** is so slow. I have been wishing to get someone to show me. I know I'm not the only one with a H/C/I N/A 302 setup in the Atlanta area, and I've raced plenty of cars, not yet pulled on by another n/a Mustang. Loosing just makes me more determined to make mine faster. I don't know many people with Mustangs. I hang out mostly with F-body guys, LT1's and LS1's all modded. I don't have any trouble keeping up, posing a threat, or even pulling away sometimes.
I am kind of outgrowing the heads though. I'm thinking of using part of my tax refund to start a new engine project with lightweight pistons and valve train with some nice AFR heads and custom cam with some high compression, made to revv to 7000+rpm.