The TFS TW heads you are talking about are the "G2" version that has a few of the problems sorted out that the first heads had. Keep the lift below 0.520" unless you flycut the pistons for valve clearance. The usual eyebrow or trough valve slots will not do- the TW G2 head has 16º/18º valve angles and the(intake only?) valve isn't in the same location as OEM, IIRC. P to V clearances have to be verified for all cams to be safe, including both sides of the ICL where it is to be installed.
Using the TW heads, the CR will be low- about 8.2 w/the usual stock bore, stroke, deck and piston volume specs and a 0.041" head gasket thickness. You can bring this up by using 0.028" composite gaskets ~8.6 CR), even more by zero decking the block (~9.0). More yet w/milling the heads.
The 416 heads were used on '80 to '84 or '86 (depending on where you look) 305's.
Another option is to use the Vortec 5.0L "059" head from a '96-up L30 engine.
Vortec L30 "059" casting:
LIFT Int Ex
.100" 68 47
.200" 128 103
.300" 179 138
.400" 205 152
.500" 221 163
L30 305 head info- POST #487