Dang that's a great idea for lifting the hood up, much better than cutting off the hinge pin sleeves welded to the frame and wending to a block to raise up. I will do that! I will have to do some custom work to the heat shield for sure. I haven't addressed how the new muffler will exit the tractor either.You could cut the screen in half and cut the area around the coupling to fit. I do this on stock Vanguard powered tractors. I think that the screen halves will come off the fan and out from under the blower housing. Be careful with the screws that hold the screen to the fan as there are threaded brass inserts in the plastic fan.
You can drill out the spot welds that hold the hood hinge on and make up an extension to raise the front of the hood. you will also need to shorten the heat shield in the hood as the new engine is forward. If I recall, I used 1/8" X 1 1/2" flat bar, maybe 2" and utilized the holes to bolt on the extension.
As for the screen, I think I'll do that too. On the ones you've cut, do you cut across and through the screw holes in the screen or between the screw holes? I feel better cutting it knowing someone else has done it with no issues.