13's, stock '71 318 short block.
I think if it was me, knowing that these are really place holders but possibly could be tweaked to feed a better engine easily... I'd look into RHS LA-Xs with the 1.92 intake. I know Hughes has them for $875/pr but you'll need to upgrade the springs. My reasoning would be the EQs or stock Magnums would not be enough in any form to feed a decent engine nor will they accept larger cams later. So I think overall those heads might be "the best fit", knwoing there will be changes relatively soon after I'd get the heads with more potential from the get-go.
I agree, however... using Desktop Dyno and the flow #s from Hughes' webpage, I plugged both the Iron Rams and the Indy/RHS heads into several different combos. The Iron Rams were better EVERY single time, didn't matter what cam/intake etc. I'd actually rather not use the Magnum valvetrain with all it's inherent compromises. I'm leaning towards the Indys for the above reasons, would work well ported on a future 340.
For a camshaft... You almost need to look at "claimer" type cams because you can't do too much lift with no valve relief. So I'd try to spend the coin on a set of rockers and run a solid lifter cam in it. Also, the heads are decent enough that you don't need the dual patern cam. Something like the Magnum 270S would be great in it.
I have a set of NOS adjustable rocker arms, thought about using the MP .490 solid in it. Hughes has a small solid too but it's not so great IMO. Thought about one of the Lunati Voodoo cams too, (hyd) they seem a tad bit better than some of the other 268 cams out there.
Keep the intake dual plane (Performer 340/360, Crosswind maybe?) and carb under 650cfm and I think a basic 4150 series DP would be fine.
I have an LD4B, should work OK. Was thinking about a 750 cfm 3310/4160 carb with vacuum secondaries. Quick fuel has a cool kit for 4160 carbs, they can be tricked out pretty easily. Maybe a 650 DP would be good too, not sure yet. 4160s are slightly more street friendly.
I'd also run a convertor in the 3K range.
I research converters all the time. Seems a lot of guys run the Dynamic 9.5", but I'm thinking it may be too much for this combo. I have 4.10 gears and a low gear set for the trans, might allow me to run a higher stall.
I think if the lower end is ok that combo should get you close to mid 13s in bad heat, low 13s after it's all debugged in good air.
Car has like 60-something miles on it, not beat on or anything. Have yet to do a compression test. Probably won't at this point.
It's always hot and humid at E-Town.