steven6282

Hello everyone,
I hope I'm posting this in an appropriate section that might get some feedback tonight / tomorrow morning.

First a little rundown of my situation. I have an engine that was built for me by cmengines (a fairly reputable local company) that is supposed to be a 340 hp engine. I've had it for about 5 months now in my 86 z28 with a T5 transmission. It's got a .440" flat tappet cam in it with 270 / 224 duration. The camp rpm range is 2500 to 5300. It has stock OE cast iron heads on it. And currently I'm running my stock aluminum intake from my 305 on it. It has a non cc 750 cfm Qjet on it. For exhaust I have hooker 2055 headers (1 5/8" primary to a 3" collector, 3" straight pipe to a flow master exhaust). Well I've been questioning the power of it every since it was installed, and finally took it to a dyno earlier this week. I was only producing around 234 rwhp. Even the people who made the engine said that seemed about 50hp lower than it should be on the rear wheel. Them and a few others have suggested my intake is probably one of the biggest things holding me back.

So I'm looking at replacing my intake this weekend to see how much difference it makes. I just can't find any good information or any agreeing information on which intake to go with.

The various ones that have been suggested to me, Edelbrock Performer, Edelbrock Performer RPM, GM Performance ZZ4, and Professional Products 52001 (this one was suggested by a local race parts shop, the ZZ4 and performer were suggested by members of thirdgen.org).

Can anyone give me opinions on which one would be the best and give some reasons to support it?

I don't think I need the EGR. I've eliminated my ECM in my car, and have been told by the mechanic that originally did my engine install that the EGR isn't even functioning now because of that. I've long since removed my smog pump, and I cut the smog tubes off the hooker headers. I want to keep my Qjet carb for now as I've had plenty of people tell me they are really good carbs, just a pain to tune correctly. So it would be nice if whatever intake I get supports both spread and square patterns, in case I decide to switch to a holley or something later.

On special note of the Performer vs Performer RPM. I've read that the Performer RPM makes more power at higher RPMs. I think I read the range of it is around 1500 to 6500. Would this be to high of RPM with my cam topping out at 5300? I read the Performer is good for idle to 5500, but I was worried about losing to much power at the top end (which I think is what is killing my horsepower now with the stock manifold).

The professional products I haven't really read much about on the net. It was suggested to me by my local race shop and they said it should be a large improvement over stock. It's also pretty cheap at 135 dollars. But that is what worries me, being that cheap I wonder if the race shop is just trying to sale me something and it's not actually going to be much improvement over what I have. I think it is about equivalent to the edelbrock performer though. Looking at pictures of it, it's almost identical to it as far as looks go.

Anyway, hopefully some people here can chime in and help me decide which one to go with!