12 cylinder Boss

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RacerX

Well-Known Member
Joined
Nov 16, 2025
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543
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NC, USA
How to build a 12 cylinder Boss engine from two 8 cylinder engines. First take two printed 8 cyl boss engines do lots of measuring and careful cutting and sanding that is most important to make sure the pcs, all match up right. Then comes thinking about the accessories and how to fit them to the new long block assembly. On this one a
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hand made timing cover, fuel pump, injectors, air scoop and headers. Twin printed magnetos to make it easer to run plug wires, plus it looks kinda cool. The air scoop is two level the lower opening feeds the front 6 cylinders and the top the back 6 so in theory all cylinders would be evenly fed air. The engine build was a just because i wanted to but it eventually found a home in sand rail Helter Skelter.
 
Loving it!
Unfortunately, I know next to nothing about these engines, except they're way cool!

For now I'll keep following your builds, plugging away at my WW2 truck engines (following instructions), researching pics and real world restores, and maybe in a few years, I'll know which side is up!
 
Loving it!
Unfortunately, I know next to nothing about these engines, except they're way cool!

For now I'll keep following your builds, plugging away at my WW2 truck engines (following instructions), researching pics and real world restores, and maybe in a few years, I'll know which side is up!
Nothing but an internal combustion engine, with a big air pump on top. I think the truck builders would know this, what drag racers use as a supercharger or blower, was originally designed to work on the exhaust side of a diesel engine to help it evacuate the exhaust gasses from the cylinders and pull in more air and fuel. So one day in the late 40s some hotrodder that knew about its workings reversed that and made it an air pump instead of a vacuum.
 
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Absolutely Insane!!
Thanks brother, i love doing this kind of stuff. This is the only 12 cyl i have made so far, i also built a blown big block Chevy straight 6 from styrene stock and a couple of resin bb heads and valve covers, Its the one in the snow sled, all the other 12s that are not Rolls Royce are based on a Chevy LSX that an Australian hot rodder turned into a 12cylinder. You can actually buy a real one if you have pockets that deep. I will post the Salt Rat engine build next.
 

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