Technical Hemi crossover for blower application (From idea to production)

I could go either way, but I can certainly see the merits of going one-piece. They just look better.

 

How about making the part in one piece, but mostly a tubular shape? That way, if someone wants, they can cut it in 2 and put in a piece of hose to connect them.

 

Good thought, we will see what the response is to that idea. I think that the reason the original one was shaped the way it was is that it basically is the same as the stock one with about 1/2" shaved off the top.

 

My 0.02, I'm more interested in a one piece for my project

 

I had a related problem with my early 331 hemi. those heads of course don't have the classic hemi crossover, they have the thermostat built into the intake manifold similar to the SBC. Unfortunately those manifolds mostly are 2bbl ones, not amenable to performance application to say the least. A 354 or 392 4-bbl manifold will bolt up to the 331 heads but you lose the thermostat/water transfer function. I solved the problem by using a 354 manifold wit the front water Passover holes drilled out and short stubs of 1 1/2" steel pipe brazed into them. Then I built a thermostat module that is attached with short sections of rubber hose. Problem solved!
Here is what I needed but they are rarer than hen's teeth!


This is what is commonly available


I drilled out the carb holes to adapt a modern big carb.

I run a Holley 3bbl!


Here is the same manifold with the crossover. Works like a champ.

 

I sent the DXF files to the water jet place to have a couple sets of flanges cut out. In the meantime I can make a jig to hold the ends in place while I weld it together. This will be a couple steel welded units for testing the fit.

 

Yes it works but pretty it is not

 

So back to the 331 heads with no water outlets on the front. If I make adapters for the front of the heads they will not land in the same spot as stock because the heads don't have the meat in the corners to create a flat spot. So for this application a longer crossover would be needed the split design would work for this. A few have expressed that they want the one piece unit. So it looks like I will just have to make both. I will make the one piece unit first.

 

I will need one for my 331 if you get one to work! Thanks for all your work. Gary

 

Have you considered just making the L&R piece for the heads with more of a rounded exits that could be grooved internally for o-rings and that would accept a readily available size stainless or aluminum tube to connect the two. This would look like one piece when installed and also could be various widths for individual needs as in the early 331s. Personally, I would prefer to put temp sender at rear of intake and do without the by-pass hose for a cleaner look.

 

I had my machinest make a jig plate off of the original crossover. When I get the part's from the water jet guys I can bolt the part's to the plate and weld them together. I will be making the cross tube out of 1-1/2" box tubing. Here are a couple pictures.

 

I think the reason for the middle of the water crossover is wider is because of the thermostat area. I am thinking that I can go with 1-1/2" box section with a jog in the middle instead of the fatness that is seen in the stock one. I need to get one of those Chevy thermostat housings to be able to get the angle of the outlet right.

 

I picked up the water jet parts tonight and started to mock up the water neck. In doing that I noticed that the water neck that the PAW crossover used is a straight 90 degree. In the pictures below you will see that the same angle can be achieved by using a stock style GM water neck. So I propose to you that the bolt holes be placed parallel to the face of the block as this will achieve the angle and make the pattern easier to make. The second picture shows the orientation of the PAW unit in chrome and the new orientation that I want to do with the stock GM water neck. Please let me know what you think.

 

I have seen about a good dozen variations of water neck in the aftermarket, including ones the swivel.

I think that if the bolt holes are parallel tot he face of the block, it will be fine. There are myriad solutions for any desired angle.

Here's a sample: https://www.google.com/search?q=sbc...iumvqHn-7RAhVFKGMKHe1yBY4Q_AUI3gEoAQ&dpr=1.25

 

Don't count on using a swivel housing because they are almost guaranteed to leak.

I think it might be OK to set the themostat holes straight???

The majority of these issues seem to be only important when a blower is in play.
The bolt holes would go into water, I believe they aren't into water on the paw unit.
It will push the center line of the housing over to the passenger side a bit but how much exactly.
If I look at the below picture, rotating the T stat would put the bolt hole into the mess of casting ? And that would result in the need to move it enough to get the bolt hole out of it?

On the paw unit, it appears the used the positioning in order to move the Tstat every possible iota over to the drivers side.


How far over would it move ?
These vertical grid lines are about 3-1/2" on center

 

I do believe that I can still keep it in the same position as the PAW unit. Are there any accessory drive brackets that rely on the two crossover bolts for mounting?

 

Those bolts aren't normally used for any accessories when a blower is there.
However for a non blower application they are and so is the one in the center like that of the factory unit.


The flanges you had cut appear to be quite different than a Chrysler gasket,
the gasket is photographed on 1/4" @ 4 squares = 1" graph paper
And it follows the head's profile shape perfectly but about 1/32" larger on all sides.

 

Orientation for drivers side

 

I found the solution to leaking o-ring water necks, about a decade ago.

 

That is a leading statement, enlighten us!

 

Remove the crappy offshore, probably plastic and not rubber, o-ring, and use a real one.

I have installed more than I can remember. No leaks.

If it is from China, the more flexible, malleable, or ductile a part is, the higher the content of political dissidents, uppity ethnic minorities, unwanted girl children, dirt, and newspapers.

 

Yeah, la-de-fucking -da

How about making them look non billet traditional ?

Oh looky there-
Posted at the same time.
The load transfer of the plate sucks

 

Flap disc, file, sandblast.

 

As you know I've been reading along on this and will need one also. My question is why not move the T stat housing outboard or just over the Drive side head hole? The issue seems to be Hose clearance to the drive belt. Your casting a complete new unit so a flat spot over or past instead of inboard of the head mount bolt holes, what would it matter?
The Wizzard

 

I kinda like the idea above...there is no magic as far as the location of the t-stat is concerned.

.

 

This image gets burry when it's cropped down.
Right in this area there's 10 lbs of shit it a 5 lb bag.

There's the water crossover flange, bolts onto head bosses,

 

I will see if I can get it to the outboard side as much as possible. If this is for blower application only then it shouldn't matter if the bolt bosses are accessible for an accessory mounting bracket as long as you can get the bolts threaded in.

 

I must be missing something here?

The bosses are there and out of the way and usable if so inclined. The edge of the t stat housing runs parallel with the bolts going into the head. One t stat housing bolt is behind and the other ahead of the water passage.

^^^ that's what I get from looking at the pics^^^

Do you have a drawing or sketch showing the problems you are attempting to solve?

 

The casting pattern would be easier if they are straight across. In this picture you will see the orientation of the PAW unit on the left and my design on the right.

 

So you're saying that you are gonna change the clocking of the Tstat mounting bolts? Then we will use, what looks like a pontiac housing? Am I right?