440 build working with what I’ve got

while you've got a bit of converter and gear, that cam is just a terrible match for the stock heads and intake. also, i'm not sure how big you can go with a cam on stock heads before you start running into clearance issues and coil bind (i'd probably start checking guide/retainer clearance above 480)-- although this may be a non-issue if you've had the machine work done already.

if i was building on a beer budget, i'd probably try and flip the script on this one. adios the cam, ditch the 850DP for something a little more mellow, and see if i can turn that B manifold into an RB manifold via subliminal manifestation. big cams and DP's make for good trade fodder.

with a light car on the street, i'd go a little more subdued: smaller cam, dual plane of some type, 750(ish) vac 2ndary (or TQ/QJ twins). something like that would absolutely rip, and with the pieces you have, i'm sure you could horse trade your way to a better combo of parts.

if you wanted to spend as little money as possible, you could just stay with the stock intake, port the heads at home, and then stab in like an HP cam or a melling or summit white box. use the sale of the other parts to finance out the cam upgrade.