340 Max HP Potential with X/J heads?

MobileCustoms said
It's easy to see from my dyno sheet that my build would peter out in a 1/4 mile run with the heads I have, so that is something to keep in mind if you plan to race it at all vs strictly street driven. It might do pretty decent at an 1/8 mile track and I will probably do that, for fun. I will also probably upgrade to some better heads eventually... who doesn't want better head??? LOL

Measure your Port volume next time. People don't realize you can just make that port a hell of a lot bigger and even flowing the same will RPM higher. One of the reasons why my production head 4 inch motor will RPM higher than others with production heads is because I got the port volume to 186cc.... that's in the neighborhood of W2's. I'm a nerd about having

To anyone using production iron on a 408-410 CID small block... just open them up. You can do this without touching the short turn if you havent the shaping skill. Raise the roof, knock the link down some, open the pinch, work the straight side wall, shorten the guide 'height and length... lightly blend that all to the bowl.
Part of the reason the rpm head flows more, is mostly due to it being a larger port...the turn is not a gem by any means. Think.