John, Your bonnet patch and manifolds look good. The patch made me think of hand hole cover someone had made on my 15 27, when I first got it I thought I must get a proper cover and put it right. But the more I look at it I think I will leave It as it is. The differences I have noticed so far between the 15 27 and 20-30 are the 15-27 has the internal oil pump (mine has two for some reason) and smaller suction screen same as Cub jr, K and OK, block drain tap in differnt place and the 20 30 has small indentation in block below carb. (Correction the Cub jr has an internal suction screen)