OldIHC

Time sure has a way of sneaking past. Got all the bits together for the R-140 project down in NC and planning a trip down later this week to drop things off and hopefully meet up with my buddy who has been doing the engine swap.

Still trying to figure out the Holley 1904 carb situation. He mentioned he was unable to use the one off the original SD-240 because the mounting flange spacing was too small - says the manifold on the BD-240 replacement engine is a bit wider. Did some digging as well as asking here and it looks like the two sizes are 2 3/4" or 3" stud-to-stud. That would indicate I need to find a replacement carb with the 3" spacing.

I did notice while looking at photos that the 'throat' or mounting flange part can be unbolted from the bottom of the carb. This being the case - if I found an old beater carb for parts with the 3" spacing, couldn't I just swap that lower throat/flange mounting and use my original carb? Or am I going to run into trouble with intake diameter?

The carb is the last bit I need to get the truck running again but I've had zero luck finding a replacement so far. My buddy wants to avoid trying to swap manifolds due to potential broken mounting stud issues. He's a F.I. guy with virtually no carb knowledge, so I'm trying to find a bolt-on solution.

Any suggestions? Or does anyone have a spare carb laying around that would work? The goal is to get the truck running and driving enough to move around so we can unload and park it up here. I can always rebuild it myself later if needed.

I'll stick my neck out here and say, no, you can't just bolt the top half of the one to the bottom half of the other. The throat sizes are different between the two. The other option is a Carter YF 735S, which would bolt on, and was used on some of the earlier 220's and 240's, and which I think CarbKing would tell you are better carbs anyway.

If this were my situation, I would make a flat plate adapter to change and match a more modern carburetor to that manifold. You do not need a milling machine and certainly do not need a lathe for this simple task. Some careful measurements and the adapter will be done.
https://www.google.ca/search?hl=en&biw= ... 5uzXYI_EGU
Here are a few examples.

Boomer - a few items:

(1) The spacings you mention are slightly off. The smaller is 2 11/16 (a.k.a. S.A.E. size 2), and the larger is 2 15/16 (a.k.a. S.A.E. size 3).
(2) DO NOT MIX THE LOWER CASTING/UPPER CASTING PAIR! You will confuse the air velocity, and while I won't say it won't work at all, you won't be happy with it.
(3) Paul is right, I do like the Carter YF much better than the Holley, but have given up trying to save the world. Use whichever you like.
(4) This link to my website lists the various carburetors used by I.H.C. in this time period, and may help you to determine what to look for:

http://www.thecarburetorshop.com/TruckkitsI.htm#TkitIHC

Nikki - I love your signature.

Jon.