Thanks Rob,
You seem to have answered all my questions quite well. I do understand about the more efficient engine with the ported heads would not significantly decrease mileage due to the fact that the engine is breathing easier. Seems like a lot of the power at low end and cruising that it would be making would be from the absence of having to suck the intake through a small straw as it were. Now on the floor, yeah, it will suck more intake, producing more power due to the fact that it "gets" more air through the larger straw.
I was getting, the last time I checked, with a 750 4150 set to dump fuel was 12 on the highway. I don't want to go under 10 if possible. I had large orange cams for the acc. pumps, but smallish jets. I had an adjustable secondary linkage that would open the secondaries at 70mph, so at 65 I was running off the primaries. It was inefficient, and I got more hp when I switched to my 650, using the same set up with the orange cams and the adjustable sec. linkage, much to my surprise. It is much more efficient. The odometer was not working for a while, the speedometer cable was snagging, so I fixed that. Now I can check mileage again, with the 650, but there are metal flakes in the oil, so I have to do a rebuild. I do want to port the heads as much as possible, and put the cam listed in your first reply. I think that would work best for what I'm looking for, and fits the engine, tires, exhaust, intake, ported heads, etc, well.
My last question is carburetor size. I'm sure I could just experiment and put the 750 on it to see what it does vs the 650, but would you say the engine could handle the 750 with the cam and ported heads? I hope so. If so, what would be a good jet size to start experimenting with? I am in Tx, hot as hell in the summer, and mildly cool in the winter. Just upgraded the distributor a bit so that should help too.
Thanks,
Bob
