Advice / pointers on replacing valve seal

iirc 35ft/lbs is spec'd but ITS WRONG! Use more like 17 ft/lbs. Dont go crazy. TDC is either both valves are closed or both are on their ramps. There are 2 TDC's in the 4 stroke. It can be noted by the keyway in the crank shaft (points right up #1 crank throw) if you can get bolt out and put a mirror down there or just look at distributor and see when rotor is pointing towards #1, that will be TDC of power stroke of #1.
This is a big block with 3/8 bolts or studs.

The 17ft-lbs or 200 in-lbs is correct for the small block 5/16 bolts or studs but certainly not enough for the big block application.

FSM torque specs for the big block rocker arm bolts is 25 ft-lbs. I have seen aftermarket rocker arm/cylinder head specs using the thicker rocker shafts at 30-35 ft-lbs.