Hi,



I have a 1990 iroc and just replace the 305 TPI with a 350TPI stock. Maybe in a couple of years I’d like to add more horsepower withoutbraking the bank. I was thinking on a set of edelbrock performer RPM heads andhi-flo intake/runners. Not sure if it worthy to replace camshaft. Anyhow, howmuch horsepower would the engine gain with heads/in manifold/runners? I alreadyhave shorty hookers. Thanks in advance for the input/ideas.

Heads and runners will certainly help, however you'll still have some significant bottlenecks that will greatly reduce the effectiveness of those upgrades, namely the cam as you mentioned, but also the rest of the TPI (baseplate). I would recommend that you consider upgrading the TPI as a whole, and not just piece-parts. In other words, in addition to the runners, you really need to do the base, and then port the plenum, base, and runners as a system. Or, replace it all with something else, like a Stealth Ram. The Stealth Ram costs about the same as runners & base cost, but flows significantly better. This will allow you to get the most out of other mods like cam & heads.

With respect to the heads, I suspect that there are other heads that will work better than those Edelbrocks. AFRs are generally considered the best, but at lower price points I think there are still a lot of other options that will surpass the Edelbrocks.

Overall, I would recommend that you decide on an induction system first (modify the TPI, or use the Stealth Ram) so that the rest of your mods can compliment that choice. It's important for the whole system to work well together otherwise your gains won't be optimized. The heads, and especially the cam & intake need to compliment each other.