I pulled the manifold to port it. It makes a lot of shavings and dust, and it is easier to cut and sand it when off the motor.
I used a thin (1/8") round and tall cutting stone on the dremel (it was the only bit I had that would work, and I didn't want to buy another one). I just worked it slowly cutting away what I needed on the manifold.
It took me about 30 minutes start to finish with cleaning the manifold out. Probably even less actually.
I cleaned up the intake and smoothed it out with some emry cloth after the dremel.
Good Luck! I wouldn't waste my money on a offenhauser unless you really need to spend some money. Yeah, I am sure they really work well, but, you can do similar things to a stock manifold.
People always are trying to get more power out of the 22r. I understand, but it is only like 90 or 100 horse, if you do a few mods like headers, a weber carb, maybe a cam, etc, you get a bit more power, but it is still just a little motor. I think of all the stuff I did to my truck, the best mod for power was gears. I would do 5:29's if I could do it over-right now I have 4:88's. Second to that, the weber and a header are nice for a bit more grunt and throttle response, and honestly, that is all I would probably ever do in addition to gears.
