I put a 360 in my 41 Plymouth. It is mated to an AX-15 5 speed and 3.55 Dakota rear. I was expecting to get at least 18 mpg and maybe 20. So far, that is not the case. Here is what I know about the engine.
It is slightly oveerbored and has enough compression that I have to run 93 octane or it sounds like a bag of hammers when I step on it. It's great on 93. It idles smoothly and has great low end torque. I suspect a mostly stock cam profile. It has an Edelbrock Performer intake and Edelbrock 1406 carb. I put a 1/2" wood spacer plus the Edelbrock insulator on it to try to keep the fuel from boiling after shut down. I had to richen up the cruise mode jetting to avoid a cold stumble. I recently richened it up one more step to a #22 setup.
I have a Mopar mag pickup distributor on it with a MSD 6AL CD box and MSD blaster coil. The current distributor is set at 34 BTDC with the vacuum disconnected and has about 17 degrees of vacuum advance. It runs great but I would like to get decent mileage since I road trip this car.
Also, I have been trying to get the temperature to hang close to my 180 degree thermostat on a hot day. That was the reason for richening it up an extra step. Road tests indicated it was still a little lean.
Any advice you guys can give me is appreciated.