skullandbones

I thought I was pretty much done when I got the manifold on the second donor engine but there was a lot of cleanup to make it presentable. After the inital cleaning, I mounted the lower unit to the engine and installed the 1 in phenolic spacer I got from Summit. It served two purposes 1) it allowed enough space to install and remove fasteners much easier and also allowed the valve covers to be removed with the upper still in place, and 2) it reduced the heat transfer from the lower to the upper manifold. I'm not sure if an additional inch of "ram" would make any difference (ha!). After I wasted time trying to polish down the lizard skin surface of the upper, I deferred that til later (after starting the engine). The next task came up when I noticed that the upper had a defect I didn't like. At the entrance of the trottle body (3+ in or 75mm), I noticed a casting ridge completely around on the inside with a 90 degree edge. There were other small casting issues there. So I spent a few hours cutting and smoothing the area with a dremel and a variety of stones. The end result was a smooth transition from the opening to the graduated "plenum chamber". If you can call that a plenum, it is different from others I've seen it goes from about 3 in down to almost the runner height but wide open. It may serve as funnel to help direct the air into the manifold runners. I couldn't resist getting a 75 mm throttle body to match that huge hole. It must be equivalent to 800 CMF although the EFI throttle bodies are not usually measured in those terms. Anyway, the engine has all the air potential that the manifold will offer. We'll have to see how it works! WEK.:cool::cool: