Is there any improvement in doing this. I dont have the money to buy new and better intake manis. Im also looking at getting a set of GT40 heads or the equivelant. Any info would be appreciated.
There's no sense in porting if you're gonna use GT40 heads - the intake is a good match for the heads as it sits. If you open the heads up however, you'll likely find that all you need to port is the lower GT40 intake. It flows around 200 cfm stock - but the bottleneck is the lower not the upper. Let tmoss on the site port it for you - he can get the upper/lower GT40/Cobra/Explorer combos up into the 250 cfm range.
I have GT40 upper and tmoss ported explorer lower. Currently I have a set of GT40 P heads on it so it probably hasn't gained anything over what a non ported lower would give me but it gives me room to expand in the future. So if I decide that I want to have the Ps ported or go with a set of aftermarket aluminum heads I already have the intake done.
You'll gain HP even on Gt40 heads, but I don't generally recommend it strictly on a dollar-per-HP gained basis. If you want to build room to grow into an intake like RYC, you will see some gains now also.