Aluminum 409 Build

[BOSSMAN]

Don't hesitate to contact me if you guys need some help, be glad to share any knowledge that I have. I really like what I'm seeing here. Cool to see this style of motor progress and have been considering building one for a 63 Impala that I recently acquired. I love the R&D side!

 

[jim_ss409]

Thanks, I've got more questions than answers at this point.

Anyway, we just got back from the machine shop with the first spacer.
It fits great...

We'll have to do a fair bit of machining but nothing too difficult. We're hoping to start on that tomorrow.
It will be held down with four head bolts and several other fasteners so I think we can just epoxy it to the head. The only potential weak spot I can see is at the rocker studs for the intake valves. If we think it's too much of a problem we can weld the spacer to the head.

 

[jim_ss409]

We made a mold of one of the intake ports today.

I altered the image in this one to see how it would look raised.

The pushrod pinch is definitely a tight spot.

It shows up even better from underneath.

Dave Mills had suggested the possibility of moving the pushrods over a bit by using offset lifters.
The lifter on the left is normal and the one on the right has an offset pushrod position.

The T&D rockers are also available with offsets so moving the pushrod itself isn't a big deal.

Moving the pushrods over would be a bit of work but I'm starting to think it would be worth the effort.

We also did some milling on the spacer plate today. We left a little at the top for now in case we need room to move the valve cover toward the intake.

 

[jim_ss409]

We got the rockers figured out today. It looks like they'll fit fine.

It looks like we can only move the pushrods about 1/8th of an inch so we may try to just max out the port without moving them.

 

[BOSSMAN]

Make that pinch as wide as you can, you will need all the area you can get.

 

[entourageguy]

I stopped by yesterday and had a front row seat to watch Jim milling away on the head.

 

[jim_ss409]

I stopped by yesterday and had a front row seat to watch Jim milling away on the head.

It was nice to see you again.

Make that pinch as wide as you can, you will need all the area you can get.

Yep we ordered .180 offset lifters and .170 offset rockers so we're making the port wider. With that and using a thin brass tube for the pushrod hole, like I've seen you use in some of the heads you've done, we should be able to completely eliminate the pushrod pinch. We're going to alow room for 7/16" pushrods.
We're just working on the first port today. It's looking good so far. I'll get some pictures up later.

 

[BOSSMAN]

Good to hear, excited for the pics. Hope that offset is enough.

 

[jim_ss409]

Good to hear, excited for the pics. Hope that offset is enough.

I think it'll be OK.

We got the ports roughed in today. It doesn't look like it in the picture but they're actually a little wider than the stock ports, plus there is no pushrod pinch at all right now. We will have to extend the ports a little lower but it shouldn't be more than about 1/4"

As you can see in the picture, they're quite a bit higher. It looks like they'll be a total of 1 1/2" higher when we're done. With the heads sitting flat on the table, the old port ran uphill at an 8 degree angle, the raised port runs downhill at a 27 degree angle.

 

[Ishiftem]

You guys are adventurous!! The difference that will make will be huge!

 

[BOSSMAN]

What is the rough port dimensions now vs stock.

 

[MRHP]

I was going to mention I have seen copper tubing used in a situation like that.Most recently on some Pontiac heads.

 

[BOSSMAN]

A little Splash Zone epoxy and some .014 wall bronze tubing is pretty common on race heads.

 

[BOSSMAN]

 

[jim_ss409]

What is the rough port dimensions now vs stock.

The heads were only 2.14 square inches at the pinch before. Actually a bit less because I didn't figure in the corner radius.
Right now they're 1.32" by 2" or 2.64 square inches, again not counting the corner radius. We plunged straight in when the heads were on the mill and just broke into the old pushrod holes. We're going to bore out the old pushrod hole and epoxy in an aluminum plug. Then we're going to bore a new hole about in a position about .180 wider and install a brass tube. I did a sketch that sort of describes it. Ignore the top photo, it's the same thing but it came out small.

We'll have to make the port a bit taller and we may be able to go a bit wider. The intake valve is 2.25" or just under 4 square inches so I've gathered that this area of the port should be about 3 square inches. (does that sound about right?) We'll leave it a little smaller than that and let Dave Mills decide on the final size.
Right now, the port goes perfectly straight to the bowl and the manifold will also continue straight out with no bends. We will of course add taper to the manifold runners. The bowl area is fairly big already so I think it's in the ballpark but again we'll let Dave figure that out.

 

[BOSSMAN]

If you have a 2.250 valve typically you will run around a 90% throat so that will be a 2.030 diameter. That size of a hole will be a 3.25" CSA (without subtracting the stem size), if it were me doing the head I would make the MCSA (minmum cross sectional area) the throat. If you can make the port entrance that size or larger that's were things will be more beneficial for the project. Sounds like you are limited to width because of the offset so that is where the height can make up if needed. The other issue will be over the SSR (short side radius) because you may not have enough meat in the casting to make that the size you really need to control the air speed. I'm guessing you will need to see 3.6" - 4.0" CSA in that area if at all possible.

With a port dimension of 2.00 X 1.32 and lets say a . 375 corner radius that puts you at 2.56" CSA right now. If you offset the port width .170 that still will only put you at a 2.86" CSA. You will need to add .250 to the height as well and you will be close to the throat size at that point 3.23" CSA (2.200 X 1.490 with .375 corner radius). Hope this helps you guys out some.

Putting in an aluminum plug like what your drawing is showing is a good idea and redrilling in the new location, that is a nicer way of doing it.

 

[jim_ss409]

Thanks for that info. We're going to widen the port as much as we can once we relocate the pushrod holes, then lower the floor until we get to the appropriate CSA. Again, we'll err on the side of being too small and let Dave bring the port out to the final size. The port does open up quite a bit as it gets to the SSR so I think we might be in the 3.6" to 4" ballpark. I might slice that port mold into segments and trace them on to graph paper to check it out.

 

[BOSSMAN]

That would be a good place to start. Really the only thing that will dictate the actual size is when it is on a flow bench and you are using a pitot tube check local velocity. That right there will tell you if it is too fast. I like to listen to the heads on my flow bench cause you can hear some issues with the port - quite is a very good thing!

Here is a picture of a SBC Pro Action 12° head, notice how high the port is and how the manifold bolts are (not sure what you guys plan to do for a manifold). I think your intake port will act similar to this head depending on the SSR shape.

 

[jim_ss409]

(not sure what you guys plan to do for a manifold)

We'll build one out of aluminum. I'll put taper into the runners and use Pipemax as a guide for length and entry CSA. There will be no bend in the runners and they'll be straight in line with the ports.

 

[jim_ss409]

We melted some aluminum and poured it in to fill the bottom of the ports.

The aluminum plugs don't stick to the head and they also shrink a bit so we used epoxy and treaded bolts in from the underside to hold them in place. In this picture you can also see the knurled plug that we epoxied into place to fill the old pushrod hole. We then bored it out to take this brass tube.

We won't epoxy the brass tube in yet. That way Dave can grind right up to or even right through the aluminum and then install the brass tube. We're aiming to have room for 7/16" pushrods. I'm sure a thick walled 3/8" pushrod would be fine but they say that 7/16" is better if you can make them fit.

Here's a couple more pictures. The ports will be larger in the end but we'll let Dave figure out the proper sizing.

This head's just about ready to go. We're just waiting on the second plate to come so that we can get the second head ready. In the end the plates will get bolted and epoxied in place. This has been an interesting project so far. We've spent a lot of time milling this all out. We're lucky to be able to do this ourselves, the price would get crazy if we had to pay a machine shop to do it.