Author Topic: Sheet Metal Intake on Tunnel Port Intake Adapter (Read 8279 times)

jayb · « **on:** November 27, 2016, 09:25:35 AM »

One of our forum members, Garry C, recently purchased on of my tunnel port intake adapters and is a building a sheet metal intake for it. He asked me to post these pictures of it in process, and ask for any comments or suggestions. I'm sure he will chime in with a better description of what he is trying to accomplish; here are the pictures:

KMcCullah · « **Reply #1 on:** November 27, 2016, 10:58:32 AM »

Looks cool Garry. The runners look short to me. Is this for hood clearance issues? What kind of car is this going in?

edgarval · « **Reply #2 on:** November 27, 2016, 11:12:33 AM »

I like.

e philpott · « **Reply #3 on:** November 27, 2016, 11:23:06 AM »

Quote from: KMcCullah on November 27, 2016, 10:58:32 AM

Looks cool Garry. The runners look short to me. Is this for hood clearance issues? What kind of car is this going in?

it's just the adapter for a sheet metal manifold , runners are not done yet

GJCAT427 · « **Reply #4 on:** November 27, 2016, 11:42:55 AM »

Okay guys, What you see is a rough idea. I plan to set this up on my 63 Galaxie or my 64 T bolt clone wagon. I`m hoping to keep it under a bubble hood if possible. The runners now are at 2" into the ram box. After studying other designs I wondered about the width of the floor. Jay has suggested that they should be longer to help with low end RPM. I wondered if an inverted "V" the length of the box would help or hinder the air flow. The V would be as wide as the floor up to the port openings to allow for blending the runners. The plan is for a removeable top plate for single or dual carbs. The box sides are going to be 1 1/2 to 2" high at this point I`m thinking. This is based on a Cleveland tunnel ram I have for some reference on another of Jays adapters. Will it be streetable , I`m not sure but I plan to try it on both the street and strip. I have some othe thoughts but I want some imput before deciding. I plan tp bring the finished manifold to the Beaver next spring to show off my handy work. Oh ya the carb covers are for another project 2x4 intake I`m planning to install in a 56 COE with a 410 setup.

e philpott · « **Reply #5 on:** November 27, 2016, 11:45:52 AM »

how many cubes are you feeding ??

ScotiaFE · « **Reply #6 on:** November 27, 2016, 11:47:46 AM »

I think I would bend the sheet.
The weld will pull it hard and you may have to go back and touch up a pin hole.
Looks great.

GJCAT427 · « **Reply #7 on:** November 27, 2016, 11:53:14 AM »

427/454 possible, using a C8AX-D cam. Bending the bottom is a possibility, welding it doesn`t bother me as I can control my heat.

ScotiaFE · « **Reply #8 on:** November 27, 2016, 11:55:47 AM »

I can't so I avoid as much welding as I can.

e philpott · « **Reply #9 on:** November 27, 2016, 12:04:44 PM »

Quote from: GJCAT427 on November 27, 2016, 11:53:14 AM

427/454 possible, using a C8AX-D cam. Bending the bottom is a possibility, welding it doesn`t bother me as I can control my heat.

the bigger cubes you go the more streetable it would be with same set up , might be a good time to go with a 482 , just a thought ,,,, sweet project for sure with either car !!

Heo · « **Reply #10 on:** November 27, 2016, 05:58:55 PM »

I have seen a few intakes that was made for turbos.
Where they have the runners protruding in to the
plenum and the runners was...beveled? ..Like a
velocity stack. Supposed to be the hot stuff for
turbo plenums.But then they inject the fuel down
stream in the runner

Joe-JDC · « **Reply #11 on:** November 27, 2016, 10:15:24 PM »

I started to answer this morning, but decided to wait and see what develops with the answers. Not trying to be a naysayer, but you are building an intake that uses a 1 3/4" venturi going into what looks like over 2" diameter round tube. Unless you intend to install Dominators and spin it to very high rpms, I think you are way too big. Whatever your heads flow, whether a mild porting of 340 cfm, or radical at ~370 cfm, you only need a runner size for those intakes that is about 1 3/4" diameter at the head, and only slightly larger in the plenum for a small taper. You also will need to contour the opening into the ports quite a bit to prevent any turbulence and loss of flow. A smooth tube that is 1 3/4" diameter will flow over 400 cfm in case anyone is doubtful. We build things too large for optimum filling in my opinion. Otherwise, have fun, and keep us posted on the results after you get it running. Joe-JDC

GJCAT427 · « **Reply #12 on:** November 28, 2016, 05:50:33 AM »

Thank you Joe. Jays adapter is 2" all the way to the head, and I think the head opening is a 2 1/8"-2 1/4" semi oval. I will check the heads today to see. I just happened to have the 2" tubing so that is what I used. Any suggestions on the floor, flat vs taper into the ports? I`m going to play with template today at work and see what it looks like.

jayb · « **Reply #13 on:** November 28, 2016, 09:33:03 AM »

Quote from: Joe-JDC on November 27, 2016, 10:15:24 PM

I started to answer this morning, but decided to wait and see what develops with the answers. Not trying to be a naysayer, but you are building an intake that uses a 1 3/4" venturi going into what looks like over 2" diameter round tube. Unless you intend to install Dominators and spin it to very high rpms, I think you are way too big. Whatever your heads flow, whether a mild porting of 340 cfm, or radical at ~370 cfm, you only need a runner size for those intakes that is about 1 3/4" diameter at the head, and only slightly larger in the plenum for a small taper. You also will need to contour the opening into the ports quite a bit to prevent any turbulence and loss of flow. A smooth tube that is 1 3/4" diameter will flow over 400 cfm in case anyone is doubtful. We build things too large for optimum filling in my opinion. Otherwise, have fun, and keep us posted on the results after you get it running. Joe-JDC

Joe, can you explain a little further? What are you referring to when you say a 1-3/4" venturi? Is this the neck under the valve? If so, with a tunnel port (2.25" valves) its going to be bigger than that, probably a hair over 2". Also as Garry mentioned the ports on the tunnel port head are large, and if you put a 1-3/4" diameter tube up against the tunnel port head you would have a pretty extreme port mismatch. Just trying to understand your comments...

ec164 · « **Reply #14 on:** November 28, 2016, 08:43:30 PM »

Wouldn't the runners need to angle in towards each other as to look more at(toward) bottom of carbs?, better fuel distribution. Also with the floor so low and flat I would think raw fuel will lay and puddle..... Al

fekbmax · « **Reply #15 on:** November 28, 2016, 08:45:16 PM »

Good luck, cant wait to see how it turns out. I think it's awesome your doing this with a tunnel port.

Joe-JDC · « **Reply #16 on:** November 28, 2016, 10:52:32 PM »

Jay: On the venturi, I was referring to the two carb spacers he is using for placement of the carbs. The typical 4150/4160 Holleys are 1 3/4" butterflies. Also, with a round port, you only need ~80% of the valve diameter for optimum flow which would 1.800" inches, or just over 1 3/4" intake runner size at the head opening/intake exit. Anything more than that will lose velocity and be down on torque until the rpms build enough to keep the velocity strong. I recently watched a dyno test of a Cleveland that had killer CHI heads, and an intake that was large enough to literally stick your arm down the ports. The dyno operator tried everything he knew how to load the engine at 34-3500 rpms, and it simply would die because the airflow was too slow to take the load. Even went up to 4500 rpm and still no loading. Worked on the tune, worked on the ignition, worked on the EFI, and had two Super Flow technicians try every trick in the book to get good clean pulls. Two days wasted. Installed a different Cleveland with CHI heads, smaller intake, and instant 750+ hp. My point is that with a stock 427 TP, or even 454 TP, those ports are going to be lazy until the rpms come up. Your 585 SOHC with a 2.350/2.400/2.450 intake valve would be just about perfect at 1.960-2.000" tubes at head entrance. JMO, but that is my past experience. Joe-JDC

GJCAT427 · « **Reply #17 on:** November 29, 2016, 05:57:09 AM »

Joe I have seen where some guys have epoxyed the head at the intake to make a "D" port. this was a trick to create turbulence mid way on the runner. Do yo have any ideas on this. Also I had a friend who worked at Holman Moody back in the late 60s early 70s who worked on the first 429s. they found the runners were too smooth and let the gas fall out of suspension. There trick was to put a spiral down the runner walls to create turbulence. I`m wondering if this might work? Any ideas?

Joe-JDC · « **Reply #18 on:** November 29, 2016, 10:23:03 AM »

The ports are enlarged to compensate for the tube, but you could fill the floors by cleaning them, roughing them up to give the epoxy a rough texture to cling to, and fill the floors at least a half inch all the way to the short turn. You can do that by running a piece of wide tape all the way across the face of the head, and doubling it for strength, then tilting the head so that the short turn is level with the top of the tape. Fill each port until they run over the short turn, and let set up. Do both heads the same way. After the epoxy takes a hard set, you can shape it anyway you desire, and I would recommend a rough (36-40 grit) or even use a carbide, or stone, to rough up the intake ports. Do not polish them. If you know someone who can port them, they can actually fill the ports more and increase the short turn height, giving a much faster velocity and actually increase the flow potential of the heads. I have ported several sets of heads for other brands of engines that flow in the 280-290 cfm range that make ~600 hp, so the TP is capable of much more with some matching of parts. Joe-JDC

jayb · « **Reply #19 on:** January 30, 2017, 06:53:14 PM »

Garry sent me some pictures of the intake as it is now:

GJCAT427 · « **Reply #20 on:** January 30, 2017, 07:51:38 PM »

Ok, I made a change to the carb area after talking to my buddy Rocky. Instead of 4 holes he suggested to open it up to one large opening. I also decided to put a 3/8" bung in the back to run The PCV for the street. Also all the welds have been ground smooth and sanded to compliment Jays finish on the main adapter. Every one who walks in my shop is surprised by my workman ship on this. Some have been surprised that I even built it! People who know me are always wondering what I do for fun.

ec164 · « **Reply #21 on:** January 31, 2017, 11:19:09 AM »

So far you have great effort into this, look forward to seeing it on your engine...The open over 4 hole sounds better, make ure to use some type of shear plate also...IMO Al

thatdarncat · « **Reply #22 on:** January 31, 2017, 01:18:56 PM »

If I'm understanding correctly, you opened the area under single Holley Dominator from the 4 hole pictured to a fully open single hole? If that's correct you will want to be sure and use a safety plate under the Dominator carb. Here's a link to an example of what I'm talking about:

http://www.jegs.com/i/Moroso/710/64935/10002/-1

It's certainly something you could fabricate. The Holley Dominator is unique in that the primary to secondary mechanical linkage is exposed under the center of the carb and not external - if anything comes loose it can drop into the engine, the safety plate will prevent that.

I like the manifold project.

GJCAT427 · « **Reply #23 on:** January 31, 2017, 05:01:48 PM »

A couple of guys that race 4500s have said the same thing about a safety plate. I did lay out the carb base off one of the safety plates and I can still add it if need be. The base plate is 1/2" alum and the holes looked to be a little off after it was installed so I decided to cut it out.

machoneman · « **Reply #24 on:** January 31, 2017, 05:26:43 PM »

Oh yes, you need those safety plates!

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Author Topic: Sheet Metal Intake on Tunnel Port Intake Adapter (Read 8279 times)