Hey guys been searching this forum for a while and finally joined. New to the forum but not to third gens. It's time to upgrade the TPI intake on my 91 z28. My question is between these three intakes, which is better? My car has the 3.42 rear gear. Im looking at adding a cc503 cam. The tpi as some of know leaves us wanting more. Im not looking to all out drag race with this car. Just want something a bit better than the tpi. Not really looking for anything to turn much higher than these intakes allow. Here is what I have observed and im looking for opinions from someone who has personal experience or knowledge of them.

HSR-Good intake overall, allows you to reuse a TPI throttle body. Ive noticed most say these favor a larger cubic inch such as 383 or bigger. Cheapest option out there for the money.

GM Ram Jet-similar to the HSR. From all the dyno results ive seen it looks like it is tip for tap with the HSR. Doesnt have as much plenum volume as HSR. Cost more money and requires a LS throttle body which requires a different throttle cable to be utilized.

Edelbrock Pro Flo XT- looks to be similar to the GM ram jet. Cost more than HSR but a little less than GM ram jet. It also requires a LS throttle body and different throttle cable. I havent been able to find much info on this intake.

The question is which would be most beneficial on a mostly stock bottom end 350? Im not looking to go the 383 or other stroker options. I realize I will lose some bottom end torque but would like the intake that will work best to help get the most torque down low yet be much flatter than tpi. Sounds complicated im sure but would like to hear some opinions on which of these would be better. My engine when done will be around 9.5:1 compression ratio with a set of vortec heads that has been machined for higher valve lift and screw in studs. I would prefer to keep the happy medium 3.42 gears out back. Car is not a daily driver but would like to drive out of town from time to time. Id appreciate feedback on some of these intakes. Thanks TGO

 

Out of the three mentioned and what I have read on this board, the Stealth Ram is your best bet.

 

Another vote for the HSR. ....although I'm personally in favor of a fully ported SLP long runner set up. In fact, Steve Mack did the porting work on the one I'm running now!

I've heard the ramjet is a nice piece, and the numbers seem to back it up, but it's not overly common. (which could be good thing). I looked at the pro flow too, but the finish seems to leave a lot to be desired. Needs port and cleanup work to see it's full potential. The HSR is cheap, and works great right out of the box.

 

I have the HSR on my car. Drawback is hood clearance. My stock TA hood bracing needed to be cut by the throttle body. One thing to consider is where the intake makes its power. It is designed to run at higher RPM. The stock TPI setup is truly better for making low end power once you have some porting work done. Looking back, I wish I would have just done an LS swap...but that is another story.

 

Agreed, but there's not an intake you can put on a 350 vortec motor that won't spin the tires. Point being just because the TPI might make MORE....the other intakes still have MORE than enough!

 

Thanks for the replies. I know I can get the RamJet and the Pro Flo for vortec heads. I can't seem to find the stealthram for vortec heads except the polished version and man did it hurt my feelings.

I havent really found much info on the pro flo intake. I can find some on the ramjet and it seems pretty decent. Pro flo is a little cheaper and I do like how it looks a little better than the ramjet. I just want the best bang for the buck. I know the stealthram wins there if it is still offered by holley. Can anyone confirm if Weiand still makes the satin intake?

 

Holley's website doesn't have the satin vortec HSR listed anymore. I tried the part number 7542 and Summit Racing said it's unavailable.

 

Running HSR too and don't have any experience with the others but it runs very well. Still blows the tires out in first and second will still spin them but I'm running a well built 400. The only draw backs are hood clearance and distribution. The stock TB rubbed but my 58mm hits hard. This may be worse because of my AFR heads and thick intake gaskets so it may not be as bad with the vortec heads.

However fuel distribution, more precisely air distribution is probably still going to be an issue. It will still run well but I get a noticeable difference in plug readings between the front four and rear four. I think it's the tunnel ram heritage that's the problem.

If I were doing it over I would probably go single plane.

 

Are you using poly mounts or factory rubber ones. The stock ones are said to lower the motor a little bit.

 

It's the short runner, log style open plenum with TB in the front. Same issue with the Miniram and LT1 style manifolds. Except GM got smart and cast in some idle air distribution passages to compensate for that effect.

this is how I solved that problem on my miniram....

https://www.thirdgen.org/forums/diy-...ram-split.html

 

Thanks for the replies guys. Keep the opinions coming.

 

Agreed, yeah the front draw plenum is the main culprit. The "tunnel ram" heritage I was referring to is the grouping of 4 front cylinders and 4 rear cylinders as would be appropriate for a dual 4-barrell setup. I can't remember any other EFI manifold grouped this way. They may be in pairs but still are separated side to side.

 

When the Edlebrock Pro Flo first came out I read a car magazine build on it.The horse power numbers were pretty disappointing.

 

What if you were to modify the plenum similar to the hi-ram intake for LS motors. And what I mean is to cut the top part of the box and angle it from the throttle body to the distributor so that the front part sits up higher. Obviously it would require a cowl hood, but would this help in any way? Just thinking out loud.