Been doing a lot of research on propane powered engines since I converted my scout to propane but Im left with some confusion.
First off my engine is a 4 bolt 350 bored .040, flat tops, aluminum intake and msd ignition. Currently it has stock heads with 75 cc chambers 1.94 intake and 1.50 exhaust valves with a 9.1:1 compression and a comp 270h magnum cam, something like .470 lift and 270 duration and a power band between 1800-5800 rpms.
Now this engine was originally built for a street truck and I know my cam is too much for what Im doing now so Ive got another one to swap with an rpm range between 800-4600 and the likely hood of my engine hitting 4600 is not high, if it does happen it wont be often.
Now my dilemma is that I have a set of 58cc 305 h.o. heads with 1.84 intake and 1.50 exhaust valve sizes. Changing to these heads will increase my compression to 11 or so to 1 which is good for the propane.
My question is will the increase in compression outweigh the decrease in flow numbers? With my cam choice my rpm range is pretty low so I know my engine wont need more than a stock head and Im not looking for huge h.p., I just want my propane burner to be as efficient as possible. Mpg is key as we normally spend some long days on the trail.
First off my engine is a 4 bolt 350 bored .040, flat tops, aluminum intake and msd ignition. Currently it has stock heads with 75 cc chambers 1.94 intake and 1.50 exhaust valves with a 9.1:1 compression and a comp 270h magnum cam, something like .470 lift and 270 duration and a power band between 1800-5800 rpms.
Now this engine was originally built for a street truck and I know my cam is too much for what Im doing now so Ive got another one to swap with an rpm range between 800-4600 and the likely hood of my engine hitting 4600 is not high, if it does happen it wont be often.
Now my dilemma is that I have a set of 58cc 305 h.o. heads with 1.84 intake and 1.50 exhaust valve sizes. Changing to these heads will increase my compression to 11 or so to 1 which is good for the propane.
My question is will the increase in compression outweigh the decrease in flow numbers? With my cam choice my rpm range is pretty low so I know my engine wont need more than a stock head and Im not looking for huge h.p., I just want my propane burner to be as efficient as possible. Mpg is key as we normally spend some long days on the trail.
