The 318 with 360 heads absolutely kills compression, that's where the low end TQ goes, depending on what head gaskets you use (cheap rebuild kits are usually .054) and if you use pistons with 4 valve reliefs like most cheap replacements it is very easy to end up in the 6ish compression ratio. You need to run a 360 head milled to closed chamber and then you might as well go magnum with ports the same size as a 360 and already a good closed chamber design.

The torker was a terrible design no matter what motor you put it on, sharp angles turning into the ports causing fuel to drop out and no air gap to keep things cool.

No on the anti reversion mufflers, I don't think it would be hard to make some up (tesla valve maybe?) but I kind of doubt it's effectiveness unless you had a cam with too much overlap or something. My theory on it would be that if your exhaust flows good enough there won't be any significant reversion going on, maybe I need to try to build one for the 92 dakota.

It's not hard to make more tq than an old 12 valve, I Never could figure out why they were so popular for towing (at least in stock form), the 6.4 in my 2011 ram 1500 would destroy my old 93 12 valve in a towing contest, I just towed another 2011 1500 ram on an open trailer on a 200 mile trip and got 14.5 MPG passing 18 wheelers on a couple big passes. I did like running used oil and transmission fluid for fuel in the old cummins though, it was fun filling it with an endless supply of used oil at the honda dealer I was working at.