MTFCA Forum

Having a 1/2” plate machined at a local shop next week, and they’ll be building my “lake style” exhaust.

The measurements I acquired off the forum, that I corrected with information from original post: I also saw a post with the plate that was produced by Chaffin years ago: My question is this:

Do I need to machine indentions on the block side of the plate for the rings? Or do I have them machine it flat, and use the gasket set that’s 3 ports in one? I noticed the Chaffin plate had a flat gasket.

If I need the “indentions” (for lack of better word lol), does anyone have the dimensions? I obvious won’t need them opposite the block cause the tubes are to be welded in place.

Also, I noticed on the Chaffin plate, there’s no indention where intake would go. I’m using my stock intake, and planned to hold it in place like this picture. But how does the intake seal if it’s just flat? Maybe I’m overthinking it again!


For those interested: I purchased a length of 1/2” 16ga plain steel exhaust pipe, 30” megaphone that opens to 3 1/2”, and a U bend plain steel 1/2” as well. Machine shop said it would be cheap to assemble and cut the plate. They are going to water jet the plate, and once welded up, machine the block side completely flat.

Gaskets I was thinking about:

Hi Jacob,
Any of those gaskets will work I use the green ones between the block & header plate & the gland & rings on the intake manifold. I use a different clamping set up using fine all-thread and high nuts and a bar a crossed intake I've found its easier to work with. The high nuts are just easier to get a wrench on. Someone had a Chaffin's plate for sale awhile back.
Craig.

Craig Leach wrote: ↑

Thu May 26, 2022 12:24 pm

Hi Jacob,
Any of those gaskets will work I use the green ones between the block & header plate & the gland & rings on the intake manifold. I use a different clamping set up using fine all-thread and high nuts and a bar a crossed intake I've found its easier to work with. The high nuts are just easier to get a wrench on. Someone had a Chaffin's plate for sale awhile back.
Craig.clamp2.jpg clamp.jpg

Craig,

On your header plate, is the block side machined for the rings or is it just flat? You install the rings in the block then gasket and plate then intake? I like that way of securing the intake as well. I wish I would’ve saw that for sale I would’ve grabbed it! Also looking for lowering brackets for the front.

Header plates are flat on the block side. The counter bore on the Chaffin’s plate is for slip fitting the tube. I prefer to slip the tube thru the entire plate, leaving about 1/8” for a nice and hot fillet weld on block side. Surfacing the welds flush with the header plate creates the sealing surface. I also suggest using 1/2” material for the header plate, it will hold gaskets better as it won’t distort under clamping pressure

Hi Jacob,
The block side is not machined for rings like Kevin I like a good weld on the tube. I use VW J-tubes the are reduced at the one end so if you cut them just right and they give you a nice bevel to weld to on the out side also. I do that for extra support there is a lot of exhaust hanging on that pipe.
Craig.

Kevin Pharis wrote: ↑

Thu May 26, 2022 3:56 pm

Header plates are flat on the block side. The counter bore on the Chaffin’s plate is for slip fitting the tube. I prefer to slip the tube thru the entire plate, leaving about 1/8” for a nice and hot fillet weld on block side. Surfacing the welds flush with the header plate creates the sealing surface. I also suggest using 1/2” material for the header plate, it will hold gaskets better as it won’t distort under clamping pressure

Thanks!! So the block side is completely flat. So do you still use rings on exhaust and intake with those tripe gaskets? Now on the other side of plate; the intake just fits into the plate or is it machined? I notice on the chaffins plate the intake holes are just flat.

When I built my speedster, the pipe went clear through the plate by 1/8", and that protrusion acted as a captive gland ring and a locator so the plate could not warp. 1 1/2" tube would be too big for this.

Allan from down under.

Pinch blocks are your friend! Just Sayin'

Henry K. Lee wrote: ↑

Thu May 26, 2022 7:38 pm

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Pinch blocks are your friend! Just Sayin'

I like those clamps you got holding intake in place! Is that what you mean? Lol that’s nice!!

Yes.., our special "Dogbones" back in the day!

Henry K. Lee wrote: ↑

Thu May 26, 2022 9:51 pm

Yes.., our special "Dogbones" back in the day!

I need some of those! Lol

Hello Henry what size pipes are you using on your set up also the inlet size of intake also was the block enlarged at all cheers Warwick.

warwick_preval wrote: ↑

Sat May 28, 2022 9:54 am

Hello Henry what size pipes are you using on your set up also the inlet size of intake also was the block enlarged at all cheers Warwick.

Good question ! The diagram shows 1-1/2" port diameter and others use 1-5/8" pipe. Is this where the VW j-tube works well? It has a tapered end but couldn't find any dimensions. Price is good too for the set $27.50 + shippimg

Hello Frank thanks for the imfo you learn something new every day & it looks like the vw tubing would work cheers Warwick.

Okay to just sum up, block side is flat, use rings in block and the 3 in one manifold gaskets. Away from block can machine in a bit to set exhaust tubing into the plate if desired or just but it up and weld. 2 intake ports just leave flat on both sides? Getting with shop tomorrow. If anyone else wants one I’ll see what price is and I’ll see if they can make a couple for those interested. Would just pay whatever shipping and cost of plate is.