Thread: 350 / 305 head combo (what am I leaving on the table)

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If you use 305 heads on a 350 you need to watch the compression ratio too. the smaller combustion chamber of the 305 heads will raise your compression at least 2 points which will cause you to run premium gas and you still may have detonation problems. back about 20 years ago stock car guys did that to get more low rpm power but they ran race gas I believe. (I'm no expert just good memory)

Thanks, Yes, the old style 13x13 brass nibral prop should be maxed out by 4400 or so. Searching the net for how to calculate compression ratio. Unfortunatly it will be a few weeks before i get it to a friends shop where i can open it up and check bore and cc the head. I'm wondering what made Jasper engine remanufacturing decide to use this combination. Only reason i see so far is cost - as these heads seem to be plentiful and cheap. I know a counter girl @ the local jasper hub who takes the shop orders. Im going to see what information she can get me from the reman tag.