I'm currently rebuilding my grandfathers styled G sn/44321. It was still in all fuel configuration and am considering gasoline conversion as there is a hole in intake/exhaust manifold. Will likely need bored .090 over as its allready at .045 and #2 has pitting. I'm concerned about piston selection as I dont want to increase compression so far as to worry about it. All this tractor does is mow some pasture or toy around. A stock G all fuel as I understand is 4.2-1 but I cant find data on john Deere gasoline conversion kits (F1075R or F1076R) to judge a safe comprression ratio. Also if anyone knows the best place to order such piston would be awesome. Thanks for the help.