Keith O - sorry this investigation lead to discovery of a problem, but at least if you only use your 1650 for mowing you got plenty of time to fix the ISO-mount situation. As Matt suggested I'd definitely do the cradle modification identified in the FAQ. Also, as Richard Christenson discusses in the FAQ (seems to be his update) you usually will find the original upper ISO-mounts are still good and can be re-used. I think I'd wait till you pull the engine and see the condition of your mounts before ordering your new ones. You can describe how flexible they are, post pics of them here and get opinions as to whether they are good enough to reuse or should be replaced. The do have metal covered by rubber on the larger circular area that fits into the ISO-bar, which tends to keep the bar in position. If this is worn/torn away they probably should be replaced. And if the rubber is to squishy they may need to be replaced. Hopefully you'll be able to use the old uppers in the lower positions, and only have to get replacements for the uppers. It also sounds as tho you're just starting to punch the hole in the lower part of the shroud, and you'll be able to figure out some method to fix/patch it. Now, I'm sure we'd all still like to know if you have the 13fin K341 block, and also still like to see a pic of the frame serial/build tag. I still think you might just have a correct product/kind code number rather than a replacement engine. I suppose there is a chance the original engine failed at or shortly after delivery and received a replacement 16hp, and then someone replaced the dash decal. Suppose we'll never know but it certainly is interesting.
Tom H - did you check the op manual? I think it probably calls out the multi-purpose. I don't recall the IH number for it off hand. And whats this PEPSI stuff. We're a COKE organization, and those of us with real guts drop salted peanuts in the COKE for a sorta peanut float (Jeremiah - did ya try it yet?). PEPSI and peanuts tastes terrible. (At least when I was a kid and tried it - YUK!!!!)