[thirdgen455]

The first intake is the gutsram with Holley hi ram top 300-217 and 300-218.
It's going to need some welding and a lot of machining to finish up.

The second is my dominator efi super victor. It's already port matched to my 340+ cfm Butler heads, opened up in the plenum has the injector bungs. So I plan on running it first. I just have to open up a hole for the 4500 base.

I'd like to get some testing in on both intakes, along with 4150 efi victor I have with a Edelbrock 90 degree elbow and 90mm throttle body. Both of the hi rams are 105mm.

I'll try and start a build thread when I get closer to running. I still need to bolt the heads on and measure the pushrods, and figure out the fuel system from the fuel cell to the fuel pressure regulator and back. Also need a drive shaft made. But after almost 15 years I have almost everything to build the car.

I also want to thank Tom for helping through out the years to get this far.

[charlie66]

I like the first pic..

[taff2]

Yes, me too, although I intend doing it a little bit different on ours. I don't see the need to use the Holley lower box section-the Gutsram and my modded Offy 360 dual quad both have plenty of plenum volume- so I'll be bolting a 3/8" thick ali plate to the manifolds carb mounting flanges and then bolting the Holley efi top section to the ali plate, shouldn't be any welding or machining needed.
ps, the 3/8" plate will have radiused entries into the manifold plenum/s

[thirdgen455]

Thanks charlie!

Taff I agree about the lower, what you are saying will work perfectly. I just want as much volume as I can get. I was going to do this with my vortech box, but decided I can put it better use on another project.

This will also be boosted using the Luhn brackets and YSI I got from 4RSFEDGTO.

[Tom Vaught]

There is a relationshop between the manifold volume/velocity and the plenum volume.

Personal opinion is that the upper LS Holley LID without at least some volume below the lid will feed the majority of the air to the back of the plenum. Lean rear cylinders and rich front cylinders.

With the right EFI system you can remove duty cycle on the injectors on those cylinders but they will not make the power of the front cylinders. Just an observation from a lot of dyno testing. Marcella's intake looks the way it does for a reason.

Tom V.

[taff2]

Thanks for that insight Tom, maybe I'll have to re-think my plan, is there a certain amount of 'below the lid' volume I should be looking for? I'd like to keep the height down but don't want to give up any power, do you think a short baffle just behind the first plenum would catch and direct more airflow into the front cylinders without giving up flow?

[thirdgen455]

Thought I'd add a pic without the lower. And how the top fits to the g-ram using the topper. You can see the holley top is much larger than the g-ram top.

hope the visual helps.

[performerrpm]

man that looks cool as hell....it sux u cant just by something like that off the shelf...like the ls guys

[taff2]

Thanks for the pics thirdgen, my plan was to put a 3/8" ali plate between the manifold and the lid, with the 3/8" plate bolted to the manifold with countersunk allen head bolts, and then the Holley lid bolted to the 3/8" plate. (to save any welding or machining costs). Maybe a thicker 'spacer' plate would work, perhaps an inch thick, or perhaps just easier to buy the Holley base too!
Your first pic with the Holley base does look better from a flow point of view.

[charlie66]

Originally Posted by taff2

Thanks for the pics thirdgen, my plan was to put a 3/8" ali plate between the manifold and the lid, with the 3/8" plate bolted to the manifold with countersunk allen head bolts, and then the Holley lid bolted to the 3/8" plate. (to save any welding or machining costs). Maybe a thicker 'spacer' plate would work, perhaps an inch thick, or perhaps just easier to buy the Holley base too!
Your first pic with the Holley base does look better from a flow point of view.

If you're going to go the plate rout i would go with the biggest spacer you can fit. Better for straightening out the air for distribution. Mike leach had like 6" of spacer ... JMO

[JSPONT]

subscribed

[Chris Petersen]

I like the first picture. Back when I was planning mine, not much $ to spend. I used a victor EFI, and rails, and this elbow, had to slot the holes for it to bolt up to the intake, but works good with a cheap LS throttlebody.

[Tom Vaught]

Originally Posted by taff2

Thanks for that insight Tom, maybe I'll have to re-think my plan, is there a certain amount of 'below the lid' volume I should be looking for? I'd like to keep the height down but don't want to give up any power, do you think a short baffle just behind the first plenum would catch and direct more airflow into the front cylinders without giving up flow?

Looking at my intake again, the Gutsram V shaped plenum (with Holley Top and Bottom Piece), I think you could remove about an inch (or a bit more) from the Bottom side of the Holley Piece (Retaining the upper lid mounting bolt pattern flange) and still have adequate plenum volume. In my case when I removed the Upper Nash Dual Quad plenum I just had the runners so I had to get some of that plenum back with the Upper and Lower Holley pieces.

Tom V.

[hgerhardt]

Back when I was designing my carbon-fiber EFI intake, I had no idea how big to make the plenum, so I asked Ken Duttweiler his opinion. He said to start with the same displacement as the engine, so mine is about 440 cu in. It makes a little more power than the best carb/intake combo I ever tried, so must be reasonably OK.

[Tom Vaught]

Mr Duttweiller is one of the people I was fortunate enough to be introduced to (by my friend Dave Austin (Turbonetics and Vortech Supercharger Tech Expert)).

Very Modest Gentlemen, with a vast amount of Boost Experience.

Tom V.

[taff2]

Thanks Tom. I've also thought that as the Holley lid is longer than the Gutsram or Offy intake- the lid could be offset towards the front of the manifold by around 2" - thereby giving the airflow a longer path in which to turn into the front runners.

[Tom Vaught]

That would work well, TAFF, and actually allow the air to make the turn into the front runners a bit easier too. You would have to mock it up to see if moving the lid forward caused interference on some hood lines of the vehicles.

If no issues, simple to make a base plate that was moved forward and had the LS Bolt Pattern.

Tom V.

[AIR RAM]

Im actually really happy to run across this tread. I'm planning with my current 498 build with approx 15lbs boost. My goal is to have a FWD facing throttle body, Intercooler and manifold all tucked under a factory style 69 Firebird hood.

Perhaps adding an intercooler between the Holley High Ram Top and the intake would add much needed volume as well as cool the incoming air at the same time. They do make bolt on Intercoolers for that intake... just need to adapt it to the lower.

Over the past couple months, I have come up with a couple combinations that Im looking at however I'm leaning more towards #1 at the same time, the 671 intake manifold is basically void of any real runner length... So I would prefer to manage in longer runners.... somehow... which is why I came up with #2.

1) 671 lower intake manifold + 671 4" Intercooler + Holley High Ram Top. The only adapter that would need fabrication would be the plate between the top of the intercooler and the Holley High Ram top. This would stack up approximately 10.5" from the bottom of the lower intake manifold. It Should/possibly clear. Could come down an inch on the Intercooler.

2) Dual Quad + Adapter plate + Holley High Ram 2" Inter-cooler and then Holley High Ram top.

3) Take a Victor intake to Wilson Manifolds and ask them to modify it to include intercooler and low profile throttle body mount location. Basically tell them what i need and then let them have "Their way" with it.


Both set ups would be MPFI with a single bore LS 105 throttle body.

What MPFI system do you plan to run? What throttle body do you plan to run with it? Does the kit your planning on using use GM LS style connectors?

Looking forward to seeing what you end up with.

NICK

[taff2]

Larry at Wenzler just shipped our Gutsram intake, I mentioned to him that there is some interest in the Pontiac world for a high hp efi manifold similar to the Holley LS stuff, if enough of us email him then maybe he will cast up an efi top box and plenum similar to the Holley stuff that would be a bolt on to his Gutsram manifold, just a thought.

[ponjohn]

That is what the Pontiac community needs street or strip. (Gutsram)