225 Slant Six Manifold

chinze57 said

Yes, I believe the heat riser area Is where my issue lies. It definitely is loud and it can smell a lot more than other slant 6’s I’ve been around, good to know that’s likely where that’s coming from.

The stalling is incredibly strange to me. Sometimes, I can crank it, let it sit for a minute after revving it, and have no issue. Often times, however, i crank it and have to give it gas near constantly. I find that sometimes I can put it in neutral and not have to do that, the rpm’s will drop after idling for a few seconds, and all is good, but if it’s in drive it’ll stall after a few seconds of no gas.

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my bet is that the carburetor needs to be gone through, thoroughly cleaned, rebuilt - reassembled then correctly set up,, choke adjustments, Idle mixture screws,,,
certainly the carburetor may also just be completely worn out, vacuum leaks around the throttle shafts, fuel bowl lid warped,,,

IIRC there is a 1/8" variance allowed (anyone confirm this?) on the runners but the heater must be flat as well as the intakes stove underside.

1/8 inch warpage seems like a lot, the stock gaskets could not seal that, with that much warpage I would think the sealing of the intake manifold to the head would be compromised. I don't deal with stock style exhaust / intakes, but I would think that flatness no greater that .030 would be max. The manifold flange faces are more critical to noise and engine performance than the stove faces....

A good machine shop could take the intake and exhaust manifold as an assembly, like they are mounted to the engine and mill the flanges so they are all in the same plane (flat). The mounting surface on the cylinder head also needs to be clean and flat.