I just installed a big max mr heater garage heater 50000 btu's I dont want to install Thimble, because there is new siding can I simply put pipe through to vent and leave vent pipe away from vinyl siding
I hate to be that guy, but you should contact a professional so you don't burn down your garage.
I'd like to say as politely as possible that if you don't know if two piece wall thimbles are available, there will certainly be other questions you won't know to ask that have potential to burn your building down, or poison you with CO emissions.
I wish you the best of luck with getting your heater going.