Slant six single, to slant six double.

If it helps your thought process...

The slant in my truck is a low-to-middlin' build. About 8.2 compresssion, oversize valves, head cut .060 with a light pocket port job. Offy 4-barrel with an AVS2 500 carb, Clifford shorties to a single 2.5" exhaust. 833OD with 3.55 gears and 28" tires. It will very much get up and go if you want it to, even in a heavy non-aerodynamic vehicle. YMMV of course, but this thing is a hoot to drive.
what are you running for a cam in that? something like this is what I'd like to eventually put in my duster with my A833OD/3.23's/27" tall tires...though I am smitten by the Aussiespeed Hurricane long runner manifold....I'd be looking for idle-5000 RPM performance....was originally thinking 2bbl, but a small 4bbl might actually be more economical in cruise with the smaller primaries....not much in the way of progressive 2bbls out there....