well, i had it for 3 years. it runs nice, idles pretty nice too. I would not say it runs sluggish, it just seems to wake up at 2000rpm at which I go about almost 55mph. the problem is that I have NO idea what the cam specs are.
I have 12"Hg in park and 8"Hg in Drive. when I cruise and close the throttle, It shows me about 20"Hg..
Do you know what rearend gears you have? 55@ 2000 suggests highway gears, although we don't know your tire size. And if a stock converter, if it's a bigger cam, it might explain the big drop at drive-idle-stall?
I could get about 11mpg out of it in the summer with a holly carb. Now, I only have 200miles on the efi and just started adjusting it a little leaner (was running quite rich in certain areas at lower rpm). I also drove with a little heavier foot but damn, i thought i would get at least 14mpg right off the bat.
Agreed, give the EFI some time to optimize.
dont have a compression tester but tested a while back with my thumb on the holes and compression is there, plugs all look nice too. it could be that maybe the engine still is a little worn on the valves, it looked very dirty when I had the intake off 1 1/2 years ago and there was quite some carbon on the valves, seafoamed it twice. My rockers were super worn and I have already fixed that with new ones, that made it run better. Judging by wear and how dirty it was, the motor probably has 100.000miles on it. It has a edelbrock performer intake, pertronix ignition with flamethrower coil, fitech efi with edelbrock fuel sump pump, electric fan, 90amp alternator, small holley mighty mite pump back at the tank, 160° thermostat. I have also done a lot of electrical work and rewired and put a seperate fusebox in for accessorie safety. plugs, wires and dizzy cap are in good shape, like new..
I would recommend a 180 or 190 T-stat, that will help the engine warm up a little sooner, and that's good for atomization and MPG. Also, if your heat passage in the heads and intake are blocked, I would recommend opening that up as well. This FiTech EFI is a throttle body, so it flows wet thru your intake (and heat helps atomization), but it's different from all other TBI units. Typically an injector sprays onto a throttle blade, and the turbulent flow on the blade helps to atomize. The FiTech does a circular squirting-thing, and I don't have an understanding if that's good for part-throttle atomization.
The reason I asked about compression: if the cam has a lot of overlap, and if cam timing is off, that will cause cranking compression to drop (and dynamic compression too). You cannot check this with your thumb, though, you need actual numbers to evaluate. A 100psii cylinder will blow your thumb off, but that's too low and a sign of a problem. A cheap gage should be $20 or less, and it's a great thing in your toolbox.
I agree that 20 initial is quite a lot but it dosent kick back and for "performance" engines not THAT uncommon. It starts just fine, cold and hot. i actually found a shop manual saying 22° initial for a 1978 (my motor) 360LA. The 7.6mpg is all city driving btw. when I do more backroads and hwy its about 10mpg. I read that 10 to 12 is pretty common for a 360LA. but have only seen 12mpg once in the 3 years..
If cam timing is retarded it won't kick back as much. Yes, I have also heard that 360s are gas hogs. I've never owned anything that required 20+, but I believe your statement about a shop manual.
Without knowing what cam is in there, and not knowing other specs on your engine, I wouldn't say a 78 360 with a cam is a performance engine. Meaning, just having a cam in there doesn't automatically put it into 20deg timing area.
but I did notice, the motor does not like to be too lean at idle.
From what I have read, not uncommon for a performance engine (there, now I'm the one who said it!) to want an idle richer than stoich.
Ultimately, my advice is to figure out where you're at, with compression and cam timing, rather than trying to make adjustments (although I understand that's an easier thing to try).
