i have the gold Crane alum-body roller rockers under my cast alum valve covers. you can't run the tall valve covers, probably wouldn't be able to remove them to check valve lash, etc, with the factory booster, but you can use the medium-height valve covers. Mine aren't pretty, but you get the idea for clearance by the stock factory brake booster.
also, I have a 700R4 in my car, if you use the trans mounting boss that's part of the trans case, instead of the trans mount on the tailshaft housing, you can adapt the C3 TH350 adapter that goes in front of the trans cross member, I think you just have to elongate the slot, something like that. for my TCC engage, i only use the 4th-gear pressure switch. I found that the vacuum disconnect switch, and the brake light switch disconnect were not conducive to around-town driving and highway cruising, actually, they were annoying. The trans has been fine for quite a few years now, it's got a few extra clutches, other fixes that were recommended in the ATSG tech manual. I used it as my daily driver off-and-on for about 10 yrs. it looks it.
Once I had the engine in, and the trans mounted, I took some measurements and ordered up a driveshaft from Denny's. They were pretty quick, fit perfect (of course, dependent on my measurements). I used Moroso solid steel motor mounts, and a polyurethane trans mount. Do not ever use a steel trans mount, for sure you'll crack the trans case, regardless, whether it's a Powerglide or a 4L80E.
I used the LS7 (BBC) oil pan, not compatible with the PS hydraulic ram. drove it with no PS for a long time, just recently installed the Borgeson box. Obviously, the 1970-vintage LS7 Mark IV BBC oil pan is not compatible with a Gen V BBC (1-piece rear main seal).
I had Hedman headers, but recently installed cast iron exhaust manifolds. I generously ported the insides of the exh manifolds, gasket matched the ports, and hogged out the outlet to 2-3/4". and used 2-3/4" SS exhaust pipes to the crossmember, 2-1/2" to the back.