Turbo 232

Racekilla's thread is great. He's clearly got a lot of fuel and carburetion knowledge and experience. Fuel will be a lot of work. Fuel injection is a common path to success because you're pumping only air. A long intake system filled with 5 psi fuel:air mix would make a heck of a backfire.

"Most" turbos these days -- as far as I know -- do not have seals that tolerate fuel in the intake. All turbo cars these days are dry manifolds, fuel injected at the port etc.

Corvairs had a nifty little draw-through turbo, but the goal there was I think? 140hp, and the turbo had carbon seals or something to deal with the solvent passing through them (gasoline). That equipment is now very very old and expensive.

You don't need a turbo manifold or intake. The most common method of installing a turbo on an AMC six is to run the stock exhaust manifold with a pipe running from it under the engine and up to the turbo on the passenger side. A blow-through carb system then just needs a carb made or modified for such (you can buy Holley 2V and 4V for turbo apps) and a tube running from the turbo to the top of the carb. Some people wrap the crossover pipe to retain more heat.

The biggest issue with boost is static compression. A 71 engine should have 8.5:1 compression stock. With 5 psi you will have the equivalent of 11.5:1 compression. With 4 psi you'd have the equivalent of 10.8:1. I wouldn't run more than 4 psi, and even then you'd need premium fuel and some sort of spark knock control.

You will probably be better off to simply change the cam to something like an Isky 256 Supercam or 264 Supercam, or a Comp 68-231-4 or 68-232-4. I prefer the Isky over the Comp because of the quick ramps of the Comp Xtreme cams. Comp no longer lists their older High Energy cams, but will still make them. You need stronger springs with the Comp cams, but I'd get Crane or Mopar Performance springs instead of the really stiff ones Comp recommends -- unless this is going to be a drag race motor run at max rpm a lot. A better carb and intake would also help. If you want to go to a header do the 4.0L head swap -- it's generally about the same cost as a 258 header and the head flows better. The factory header is great, and the cam and intake will complement the added flow of the head.  All in all I think you'd be better off and have about the same improvement as 3-4 psi of boost (on a stock motor). You will get about 0.7:1 increase in compression with the 4.0L head. If it needs rebuilding have it shaved about 0.20" and get a another 0.25 or so compression, bringing it up to 9.00-9.25:1. That might need mid grade fuel to run best, but can be tuned to run regular.

That works, though a blow-through system is much easier to setup. If I had something like this (Buick GN is similar, at least the early ones are) I'd use it though...