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Cheap aluminum cylinder head castings-Chop'N'Swap project.

General engine tech -- Drag Racing to Circle Track

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Xnke
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Cheap aluminum cylinder head castings-Chop'N'Swap project.

Post by Xnke »

Doing a 4.3L aluminum head conversion for myself. I got T-boned by a hyundai doing 50MPH in my supercharged 3.4L S-10, and the new truck has the bigger 4.3L this time. Order of operations is still the same: Get an aluminum head conversion going, set the compression ratio to 9.0:1, and build a blower system for a fuel-injected supercharged pickup truck engine. I'll probably still use the same Crane Cams lobe profile on the cam that I did in the 3.4L, it was a fuel sipping machine on the highway as long as you kept your foot under control and still made good HP.

What I need, is photos of a 350 Chevy V8 cylinder head cut in half, through the head bolt holes. I am trying to plan how I'll weld it back together, as I have to remove one of the center two cylinders from the head casting. It's not much different from the 292 head conversions, except I'm removing a chamber from the middle, instead of one from the end.

The plan is to do this on a pair of 175$ brand new Ebay cylinder head castings, and get the process down before I hunt down a set of canted-valve aluminum heads that have some chamber damage in the center cylinders.

Anyone got some photos that show a 350 Chevy head sectioned through the head bolt holes between cylinders?
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Re: Cheap aluminum cylinder head castings-Chop'N'Swap project.

Post by mag2555 »

For way less money you can get a cracked head from a junk yard and then have a machine shop or electric shop band saw it up for you.
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Re: Cheap aluminum cylinder head castings-Chop'N'Swap project.

Post by PackardV8 »

An interesting project and it would be fun to work along with you. My machinist would then hate us both for once again getting into such weird shite.

Any non-import engine shop junks cracked SBC heads daily. The problem with using one of those instead of the actual aftermarket castings you plan to use is none of the variations with the same head bolt holes have exactly the same coolant passages. Aluminum aftermarket is often quite different internally than OEM iron. Not even all OEM iron heads are the same inside.
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Re: Cheap aluminum cylinder head castings-Chop'N'Swap project.

Post by Xnke »

That's why I mentioned I was going to be using the cheap ebay heads-I have dug around a little and the consensus on speed-talk is that the heads I plan to use are copies of the Dart pro-1 Platinum head design, which seems to be a decent place to to start. Certainly where I'll be able to afford to start, as a pair of heads is 350-400$ wheras a SINGLE, bare Brodix V6-8 head is 1400$, best price I can find.

I'm thinking I might use one of the early CPI "vortec" lower intakes, the early one with the cast aluminum upper intake manifold and all the injector bullshit down inside the manifold, as my starting point for the intake manifold. These do NOT fit actual 96+ vortec cylinder heads. They have the old bolt pattern, which is what I think will be on the aluminum heads I can afford to cut up.

This is the intake I'm talking about:

Image

Lots of grinding to remove all the extra gasket face, and leave only the central runner area unchanged. A new upper would bolt down, similar to the 5.0EFI ford intake, and then more standard MPFI fuel injectors would be fitted instead of the old poppet type injectors.

Other options might include a cut-and-shortened 350 TPI intake, but I hear they're a bit restrictive and low-revving, which might be fine in a pickup truck.

I'm not opposed to finding an old Magnusson blower intake for a 350 and shortening it up again, I've done it before and it works out very nicely for a good supercharger starting point.
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Re: Cheap aluminum cylinder head castings-Chop'N'Swap project.

Post by FC-Pilot »

You can get 18 degree heads bare for under $700 Each right now at Jegs. I would do that and skip the time spent on trying to weld heads and fighting that mess. I would then invest my time in welding up my own custom intake. A good 18 degree head and a proper intake will make way better power than some cut up sbc heads. Now that is just my opinion so take it with a grain of salt.

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Re: Cheap aluminum cylinder head castings-Chop'N'Swap project.

Post by ProPower engines »

Xnke wrote: Sun Jan 10, 2021 3:34 pm That's why I mentioned I was going to be using the cheap ebay heads-I have dug around a little and the consensus on speed-talk is that the heads I plan to use are copies of the Dart pro-1 Platinum head design, which seems to be a decent place to to start. Certainly where I'll be able to afford to start, as a pair of heads is 350-400$ wheras a SINGLE, bare Brodix V6-8 head is 1400$, best price I can find.

I'm thinking I might use one of the early CPI "vortec" lower intakes, the early one with the cast aluminum upper intake manifold and all the injector bullshit down inside the manifold, as my starting point for the intake manifold. These do NOT fit actual 96+ vortec cylinder heads. They have the old bolt pattern, which is what I think will be on the aluminum heads I can afford to cut up.

This is the intake I'm talking about:

Image

Lots of grinding to remove all the extra gasket face, and leave only the central runner area unchanged. A new upper would bolt down, similar to the 5.0EFI ford intake, and then more standard MPFI fuel injectors would be fitted instead of the old poppet type injectors.

Other options might include a cut-and-shortened 350 TPI intake, but I hear they're a bit restrictive and low-revving, which might be fine in a pickup truck.

I'm not opposed to finding an old Magnusson blower intake for a 350 and shortening it up again, I've done it before and it works out very nicely for a good supercharger starting point.

I would go with the later vortec style heads.
I am in the middle of finishing a super charged 4.3 build at present.
I went with the later vortec heads because they are easy to get
You could get an MPI intake from a later model truck and modify it.
The newer vortec head would be easier to modify and only requires 2 bolts at each end.

You can also contact some of the manufactures in China that produce a lot of the econo heads on the market as they will sell you a single new finished casting for about $120 + shipping to you if you tell them you want a test piece to work on or compare against other heads. They also sell them with dual bolt patterns for early and late intake styles.


Here is a like to some heads
https://paceperformance.com/i-6254980-1 ... -head.html
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