dome pistons

My brother has super h & wants to put dome pistons in plus use a head off of a 350. Will this work ok. thanks for any info.

they had high dome pistons for a h or sh at napa . I don't know if that's still so but they will improve your sh by 15 percent maybe more . don't try using regular gas with this setup use aviation fuel or racing fuel . gas knock will send those high domes out the exhaust valve in a heart beat . high domes took my 450 from 54 to 70 hp , a real nice gain .

High compression pistons and a 350 (C-175) head will work on the H. The valves are bigger in the 350 head so it is a plus. The high compression pistons are going to be a little problematic. I doubt you find anything "off the shelf" for this engine other than a set of IH style Firecrater pistons. These were the pistons that were designed to be used in the high altitude engines from the factory. They will up the compression some, but I don't have a number. I have several H's with them and they did make a difference in performance. If you really want to increase the compression you will most likely need a set of custom pistons. That would entail a complete engine tear down do. If are going that far you might as well stroke the crank. This becomes an expensive spiral. You need to ask yourself how are you going to use this tractor such as what classes and who are going to be pulling against. If you are just pulling stock classes (3 mph) the head and Firecraters will work fairly well. If you are pulling 4 mph and up you will need to go all the way. Stroke the crank 1/2" or more; run the block sleeveless; rework the carb and the governor and off course custom high compression pistons.

Just my humble opinion, from my own experience.

OTJ

Super h and 350 is same head casting. What you want is super h firecraters and a gas h head and mill the head. You'll have to do some light clearence work to clear the head. Mine makes 170psi and runs on 87 just fine. Stay away from aviation fuel.

The guy called them dome but they are stepped or firecrater not sure , but not dome. thanks for info.

have some pistons made , but your not going to get a big boost until you get that static compression up to 250 . I had 170 psi with stock pistons .

(quoted from post at 18:52:09 11/18/18) have some pistons made , but your not going to get a big boost until you get that static compression up to 250 . I had 170 psi with stock pistons .

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Needs the camshaft ground to match the mechanical compression ratio and the intended rpm range .