oh ok! same as my grandson but his is moded to stage 2 and it made a big difference! I personally wouldn't buy a new type engine till its proven!!! I would wait a while, but that's just me! you know they will be more expensive for sure!! good luck!!
bigger carburetor, changed the cam, better valves? its not bored out! I think that's when you get into a mod 3? I think if you go to www.mudmotortalk.com they talk about a lot of that stuff! try googgling moding a vanguard 35hp?
forgot also changed his exhaust that made a difference too! he changed it b4 he got it moded and it helped then too! but after he got it moded he had a crack in the exhaust and put his stock exhaust back on temporarily and it lost some power and when he got the exhaust fixed and put it back on it was much better with the aftermarket exhaust gained power back !dont know what kind of exhaust he got but I could find out if u want?
ya I thought also if u have EFI that you can put mods and the EFI would adjust itself to the mods? well, that shows you how much I know!!! if someone really wants to know just call hoyt or kyle at gatortail, 3372294864! hoyt is the one that does the mods!
Prodrive has/had an after market EFI kit that was around $1900+ and was programmable (term might be self mapping). Both Gatortail and Prodrive are selling the new Briggs 37 EFI motor. I think it is ad additional $500 over the carb model and just started shipping on the Jan 1. I'm Mud Buddy will follow suit.