The closed chamber heads are 107 cc,they have 2.06 in and 1.72 ex valves.Ive owned 6 vettes of different yrs including a 68 L-72 with 3.08 gears and a 67 L-72 with 3.73s,both had factory side ex.I would keep the 3.76 stroke crank and just build a 430.The cam will dictate how much comp you can get away with as its cylinder pressure that either bleeds at low rpm with a narrow lobe separation cam or builds pressure early with a wide lobe.Duration also plays part. Go with something along the old L-88 cam as it was long on duration and not so high on lift. Plus its a solid.Hydraulics are for lazy people. If the lash is correct, it doesnt require anymore maintenance than a hydraulic,just use poly-locks.Go to this link and look at the cam specs, its a real nice street cam. Ran em a long time,no issues. If you want to really help the geometry of the rockers,use boss 302 ford rockers as they are 1.75 ratio and use a rectangle i guess you could call it rocker ball that also has an oiling groove and is flat on top.
As far as the heads,youve got the heads that will work,just port match em and do the bowls,put 1.88 ex valves in and leave th 2.06 in.Use a bronze guide,mill to get decks straight as a bbc head is usually out by .010 to .012 on the deck warpage.Use 7/16 pushrods and guide plates. I used to have alot of ex guide issues with the stock 1.7 rockers (this was before i got smart enough to do the geometry and measure for the correct pushrod length and the 1.75 cured it)
Use a cloyes true roller and leave the cam straight up.10.0 to 1 should be fine with about 34 total timing. Dont go for the high volume oil pump,not necesarry,just use a pressure pump.The factory 427 cranks are already hot rod approved. My last 427 made 521 hp at the flywheel and was driven daily making 11mpg in town and 17 on the freeway. I like a forged piston with 1/16-1/16-3/16 ring package rather than the 5/64 (read easier to obtain and more common) plus depending on how you are going to hone the cylinders,moly or cast iron rings work fine and are dependable.
No subsitute for cubic inches huh? We just won the march meet at Bakersfield and are the fastest front engine T/F car on the planet at 269.08 in the final and threw the blower belt off before the finish line and its only a 407 cu in engine.
Oops,just about forgot the link