I am putting together my 420 ci small block and I am using a Moon Cross Ram Weber Intake, that has 45 mm in diameter runners. I machined it so it fit 60 mm throttle bodies, as it is set up for FI.

What should I use to port out the inside of the rest of the runners? Extrude hone? Just a carbide bit and electric grinder? If I punch through the wall, I know that it is easy to patch up, but what is the company that makes the patching material?

Thanks in advance

 

This could present some problems. My assumption was that the whole system was designed to fit the SBC. Never assume.

My first take would be to smoothly taper the cast aluminum runners from the port shape at the head to the round shape of the 60 mm diameter tubes (I thought they were 2.5 inch [63.5 mm] throttle plates). How long are the cast parts with the throttle plates? By the way, the 10 inch length we discussed was from the head surface to the end of the pipe.

If you've not done this before, you might get someone with experience to look at it and give you a quote. SStrokerAce said he'd look at it; it's basically like porting 8 TB's, and he's doing many of these a week. Done improperly you're going to screw your airflow. Extrudehone probably isn't the way to go, and would be more $ than having them hand ported.

Any chance you could post some pics of this setup?

 

Jon- You're correct about the throttle plates. They are 2 1/2 inches or 63.5mm in diameter, but I was being lazy.

The Weber Cross Ram setup was designed for the 1963/64 Grand Sport Corvette. The engine was a 327 small block stroked to 377 cubic inches. The carbs used were 4 58mm Weber carbs, attached to this IR intake manifold. A website that is doinga restoration on a '63 GS Corvette has pictures of this manifold and carb setup.
The link is http://www.grandsportcorvette.com/gs/power.htm

I am only using the manifold, as I am converting to EFI. So machined it to accept 63.5mm throttle bodies, using an adapter and enlargement of the intake bores.

Obviously the manifold did not come ready for 63.5mm throttle bodies, so I would like to help the flow as much as possible.

Now this 10 inch runner length didn't include into the bottom of the throttle body, but its only about an inch of extra runner length, which shouldn't be a huge set back.

I have ported manifold before, nothing to this nature, but I think I could do it. I have access to a free flow bench so I will be able to check my progress, or lack thereof.

What is the company that makes manifold and cylinder head patching materials. I have drawn a blank.

I would love to post pictures, but I am poor in other areas besides my car. Christmas is coming soon though, maybe my gf will buy me a digital camera.

Alright thanks,

Ciao

Hunter

 

Hunter,

The length that Old Stroker gave you has to be exact. So from the head mountin surface to the open air there has to be 10 inches. Not 11", 9, 9 3/4, 10 1/4", the exact number.

I am even more **** than that. I have a single plane Super Vic that has every runner epoxied up to a different size because they are different lengths. This all matters!

Like my father said. I would look at it for you and help you out for a price, but it needs to be done exactly right. Engine building is a art of little things and small details. One thing does not make up for something else.

BTW there are alot of things that can be used to fix a intake. Welding and epoxy are the main two.

Bret

 

Bret,

I understand the importance of accuracy when builing an engine. I misundertood the question and so now I have the real answer.

The length from the head mounting surface to the actual throttle plate is 11 and 3/4 inches. From the head mounting surface to the end of the throttle body housing, is 12 and 1/4 inches. There are induction stacks that can be attached to the throttle body housings, and I can make them up to 11 inches, since they have to fit in my engine compartment.

I will go to my local machine shop this weekend and purchase some epoxy for my intake, I have a feeling I will punch through a few spots where the casting looks thin.

Thanks guys.

Hunter

 

There are some epoxies that are special for this. Welding is the best way to go. You'll want to shorten the runners about 1 3/4"

I wasn't trying to be a pain, but runner lengths are very important.

Bret

 

So I do want the 10 inch runner length then......I guess I will just have to get shorter throttle body housings.

So welding is the best way.....the intake is aluminum.....so would I use a MIG welder?

I know you weren't on my case, so its all good.

Thanks

Hunter

 

Not MIG. TIG (heliarc) done by a professional, preferably aircraft certified welder is probably the best way.

I'm still a little concerned about how the transition from 2.5 round tube to the manifold will be shaped. How long a length do you have to make this transition? If it's abrupt, there will be big problems.

Before you cut anything, let me run some more simulations with solid roller cam and the better intake inside dimensions. The 10 inch length will be from the head mounting surface to the far end (bellmouth) of the induction stacks. It sounds like it's going to be well over that now. It really doesn't matter much where in the inlet tube the throttle plates are; what counts is the tuning length from the valve to the outside atmosphere or a plenum. The port length in the head is fixed so we're working with just the inlet tube.

What will lyou be using for airfilters? 8 individual K&N types on each tube?

 

now it is my turn to be ****.

TIG welding is not heliarc welding. they are two seperate things.

heliarc is using helium as the gas, and usually aluminum and a stick to weld.

TIG is "tungsten-inert-gas". the tungsten is actually the sparking electrode, and does not get "used", that is the electrode is separate from the welding medium. which can be anything. ally or steel. it is the same as MIG welding with the exception that in MIG, the electrode and welding medium are the same.

 

Hmmmm. Here are a few opinions which don't seem to support you, conquest.


http://www.ridgenet.net/~biesiade/weld.htm


http://www.wikipedia.org/wiki/Welding

http://www.hypertherm.com/technology/plasma_history.htm

http://www.daytonamig.com/faq.htm

http://sbvc.sbccd.cc.ca.us/divisions.../html/weld.htm


Maybe we need to discuss GMAW and GTAW similarities and differences.

 

So, TIG welding, thats what I though. No experience there, so I will search around for a guy who can do that work for me.

The transition from the 2.5 inch throttle body to the manifold is not a huge transition, as both are round, but the diameter of the manifold runners are much smaller, maybe 1.75-2 inches.

So, after careful measuring, I came up with this

Length of air filter(K&N as you menmtioned)-3 inches
Length of removable induction stack-from 0 to 12 inches
Length from head surface to end of manifold runners- 10 inches
Length of throttle body housing-3 inches

This leaves me with a minimum intake runner length from head surface to air filter of 17 inches, and a maximum of 28 inches.

So hopefully that will help tune in with the solid roller. I can can bascially any combo of lengths between those two extremes. Just tell me what works best with the solid roller cam you may be using.

Thanks

Hunter