Hello I have a farm all m that pulled 248 and 255 was first this tractor was pulled out of a fence row about a week prior. I was wondering if I could drop a 450 gas head on it with a 450 intake and carb. I was wondering how to get a few more ponies out of the old girl for less than $1000 and this tractor is in amazing condition the transmission is solid with now bearing or gear noise. The steering is tight and motor runs perfect it has 14.8x38 tires and a c248 up out of all my tractors this is my favorite and I think she could bring home first but she is bone stock what parts and modifications do I need to do to make it run for first and run all day long I farm with a pare of m"s and this is my go too thanks for everything and I want to upgrade her this year and maybe some more the next

A 450 head and a 450 propane manifold will help. A tune up wouldn't hurt, I'm not sure about the carb, drop the belly pump if it has one and put some money into welding up some weight bars that will bolt somewhere around the rear wheels, we have some fabricated that use the belly pump fitting holes in side of the bell housing to hold weight bars. ~Anthony

(quoted from post at 12:21:24 02/24/14)
Hello I have a farm all m that pulled 248 and 255 was first this tractor was pulled out of a fence row about a week prior. I was wondering if I could drop a 450 gas head on it with a 450 intake and carb. I was wondering how to get a few more ponies out of the old girl for less than $1000 and this tractor is in amazing condition the transmission is solid with now bearing or gear noise. The steering is tight and motor runs perfect it has 14.8x38 tires and a c248 up out of all my tractors this is my favorite and I think she could bring home first but she is bone stock what parts and modifications do I need to do to make it run for first and run all day long I farm with a pare of m"s and this is my go too thanks for everything and I want to upgrade her this year and maybe some more the next

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That is pretty darn good. Yes there are some things you can do to up the HP. A 450 head alone might cost you $1000.
Out past 255 the going gets tough and that is where weighting, hitch and traction come to play. Good Luck.

I love to see people take an interest in antique tractor pulling. Started on an M myself. Your best bet would be to rebuild the engine, or better yet, find a C264 or C281 block and rebuild that and run it if rules allow. Heres some simple tricks that will make you a bit more power. First, get an IT manual and set the governor to carb linkage correctly. Second, take the governor spring to the hardware store and match it up to one with just a bit heavier spring tension. Make sure the governor spring mounting holes arent worn out, they shouldnt look like an egg. Fire the tractor up, you will probably have to mess with the idle RPM on the carb to reset the idle. Let the motor warm up, and take a compression test. If its not over 100psi per cylinder, you may as well stop now. If it is, it should be near 105-120psi with flat top pistons, and a bit more with firecraters or step heads. If they are flat tops, dont get discouraged, they will outlug step head pistons when the motor pulls down. On to the head. You want a head with a casting number of 8060 or 8574. Those are the gas heads for an M. If you want to spend your $1k in one shot, new recast 450lp heads can be had. Dont forget to adjust the valves! If your not ready for that, the 450 gas head will work. Give it a good 3 angle valve job, and port match your manifold to the head. The propane manifold will help a smidge, but expect icing problems on humid days. On to the carb. If you can run the tractor at high idle with a stationary load on the PTO that would be excellent(dyno). When doing this, if you can adjust the high idle load screw in the bowl of the carb and make it overfuel, you wont need to jet the carb. Set it so the black smoke just clears up. If you go into the carb, youll want a #25 venturi in it. Give the ignition a good tune up as well. Plugs, copper core wires, and electronic ignition with a 12v coil work great. Take the oil bath air cleaner off and clean it out well, or get rid of it if rules allow, and use a k&n style clamp on filter on a piece of pvc pipe about 12" off the carb.

Lose all unneccessary weight off the tractor. PTO,(top steering bolster cover fits the PTO opening perfectly), belt pulley drive, belly pump, fluid in tires, etc.

Im just going to assume your allowed to have adjustable hitches. Keep yours up to the max height.

Keep at it, watch other pullers, ask questions, and have fun!