Idle screws are on all 6 bbls, front & rear are in the base , front two you say are siezed up .so that is part of the problem .
what is the idle vacuum in gear & power valve rating .
often the air bleeds are a problem & inserting a small wire into the outer idle bleeds really helps as you...
The 74 usually had a carbon canister for emissions & the shroud probably made clearance for that so the 73 will fit but you probably need to remove the carbon canister .
The way I look at most things is it is not working now so how much worse can it be if i take it apart & try to repair it , if it still doesn't work oh well ...
Basically impossible , the bows & sail panels will not work with the smaller SE window , I suppose ou could use the SE sail panels with a regular headliner & bows to make it work .All SE I have seen have the console as part of the SE pkg , no separate code for it .
All V8 K frames are similar & will work except for the Hemi .
The 318 K frame will not have the skid plate but that can be welded on if you want it later so with the correct mounts for the 440 it will drop in .
The other way to look at it is you need the cam to be its power range Before locking the converter
So for example if the cam starts making power at 2600 rpm I would use a 3000 stall .
the other factor is a cam rated for 2600 rpm will make power sooner in a 512 than a 383 so maybe 2300 rpm so a...