H manifold question

Tue Apr 10, 2007 10:05 am

I have a question about a manifold I purchased for an H. I bought it brand new, it had 300 written on the box, which I didn't question because they are so similar. When I put it on, I noticed that where it attaches to the carb is WAY bigger than the carb. The correct gasket was in there for the carb, but the bolts barely clear the manifold, and they even look a little bent. I called and asked the guy about it, he said you can't get a new manifold to fit that carb anymore. Is that correct? It does seem to work fine, if I can keep the nuts tight, just wondering if anyone knows of a source for a new one that is correct? I don't really want to replace the carb. Thanks.


Tue Apr 10, 2007 10:29 am

I think the 300 came with a larger carburetor than the H. Since the engines were similar, a 300 manifold goes right on the H engine but is sized for the 300 carburetor.

It may very well be that the H manifold isn't available unless you find a used one. The manifold they shipped you may be as close as you can get with a new part. So you may need to make some modifications for your carburetor to fit. If all of that is true, it is still pretty crappy of the place you bought it from to just hand you the wrong part and not tell you AT THE TIME that is is as close as they can get and what problems you will run into.

Tue Apr 10, 2007 11:00 am

Yeah, the guy handed it to me face to face and didn't tell me. (BTW, I later saw him on an episode of RFDTV's Classic Tractors. He had a W4 he was plowing with. Its not EASY not to mention his name. :wink: )


Tue Apr 10, 2007 1:02 pm

I cant say that I have ever seen one my self but I believe all the new aftermarket manifolds are made to fit the SH or 300 or H, The SH and 300 ran a carb the same as an M in size. where the H ran one much smaller. I believe the new ones come with holes that will fit as far as the bolts that hold the cab either the small H or larger 300 carb so I would imagine that the intake hole will be bigger for the larger carb also. It should have came with 2 gaskets one for an H and one for the larger carb. Now maybe you rec the 300 manifold and its wrong or you will have to go to a larger carb like the SH or 300 or 350 or even the M carbs will fit I my self bought a Carb and 300 manifold off ebay for my H and I run a SM carb its really hard to adjust for an H. the Gov rod is a hard fit also on the H.
So I guess I do not understand your question fully. Do the bolts match up? or not? and are they like movable to go out words or inwards for different size carbs.

Re: H manifold question

Tue Apr 10, 2007 4:48 pm

trentm71 wrote: The correct gasket was in there for the carb, but the bolts barely clear the manifold, and they even look a little bent.

If I understand correctly. The studs on the carburator barely reach through the manifold. You can get new (longer) studs from an autoparts store.

And. The sides of the bolt holes in the manifold is to far apart to let the carburator easily set in place. Couple of suggestions. Check the carburator mounting holes for burrs. Second suggestion. Run a drill bit one size larger (1/32'd inch) than the hole in the manifold through both mounting holes.