318, made changes, no gain?

I see a few things. First, the engine. As was stated a 318 with 360 heads is not 9:1 unless the machinist was really saavy. So what I think you have is "9:1" pistons but with heads that reduce that to closer to 8:1. Then that MP cam... It's way too large for that combo. If you want to verify what you have quickly, get a compression gage and take readings from the engine... Running temp, pull all the plugs, and block the throttle wide open. If it's less than 140psi that's what you have. Then there's the stock valve springs. They should be tossed in the dumpster and replaced with a performance spring, and if you have the odd exhaust valve rotator type retainers, toss them too (8 on exh valves). That cam cant make power if the valves are not controlled by the proper spring even if the rest of the combo IS matched. Lastly, the FBO ignition. You need to look at the paperwork or do some checking to see what the timing curve you have is. My guess is it might be close. But I've seen FBO be WAY off too. So it's worth it to make sure it's good enough and not worry about it.
Next the gearing. The gear change helped, but then you went to larger diameter tires. Larger diameter tires have a lot more tread contact patch than a smaller one. They also will effectively raise the rear gear ratio which as stated is exactly what you tried to change. 4" of diameter is about a full turn, so you went to 3.91s w/22" tire, and then lost a full turn, bringing the effective ratio up to 2.90s, and giving twice the contact patch. Thne you have the higher 1st gear taking more away.
You're left with a softer feeling lower end, and much less mechanical advantage with the rest of the setup. The convertor will only help if the engine is making power up that high.
I think it's a mismatch. To fix it quick, I'd replace the convertor with a cheap 10" 2500 stal, replace the gears with 4.10s, repalce the valve springs, and stick in a cam like the Comp XE262 to get the cylinder pressure back up. That should get you well into the 13s.