48 OHV intake manifolds

[koanes]

I finally got under one of my benches to look for an intake manifold a member (Bob Luland) was looking for. Sorry Bob, they are too short for your needs. I have posted a couple of pictures to show the difference between what I believe to be a 48 manifold and one from a 49. The 48 manifold is straight tube, not reduced from a larger tube at the seal bushing area. There were a lot of 48OHV made, but this is the only manifold of this type I've owned. I wonder if it was just an early version.

[Robert Luland]

Koanes I went in a different direction. I didn't know there were two differant barrel types. The 61 cu inch is 3.250 across the barrel and the 74 is 3.375. The silver soldered manifold was used 48 though mid 49. Then they went to the casted one. I have to assume that there no real date only that the factory being the cheap dicks that they were made sure they used up every last one. I ended up not being able to find a big twin unit and with the suggestion of Matt Olsen. I decided to make one. I unsoldered the branch off what I had and had a new barrel machined. This was tougher than it looks. But I figure out the riddle. When the factory made these all they had to do was center the branch and solder. Then they ran a mill down the branch to cut the hole. I on the other hand had to cut the hole with out deforming the thin tube. It’s amazing how the mind can walk away from common sense. I stared at this thing all day trying to figure out how I was going to jig it up. Time to get back to backyard tractor technology basics. With the help of Home-Puke and $3.08 the problem was solved. Soldered it together and pressure tested it at 10 psi. Dropped it off at the cad platter yesterday. Good dog Bob. You get cookie!

[T. Cotten]

I have encountered both types as well, but I can only conjure that the machined spigots were the latter production, as distortions from the heat of silversoldering are inevitable.

Beware also of the staking dimples inside of the flanges, as they are often sites for leaks. And the flanges themselves are the most malleable that I am aware of, requiring more grinding to achieve flat than most.

...Cotten