Sounds like you have a good plan. I have a 383 stroker in my 79' Caprice. Here is what I have. I put 360hp to the wheels which is right under 500 at the crank.
bored .60 over so mine is actually a 388
forged Eagle crank and rods
Speed Pro Forged pistons
10.82 CR with Edelbrock RPM Heads 64cc(a little high for pump gas but my cam helps with that
Comp Cams 268XE Flat tappet. It is very noise. Valve springs that match it
Edelbrock Perfomer RPM Intake
Holley 750 vacumun secondary
MSD Pro Billet distributor with 6AL
Milodon deep sump pan 7qt, with windage tray.
Melling High vol oil pump
ARP main studs and ARP bolts used everywhere
Edelbrock Water pump
Fluidampner harmonic balancer.
Hooker 1 5/8 Headers with 2.5" duals Flowmaster 40's
I have a built TH350 behind it with a 2200 stall converter. I had a 3,000 stall and it launched a lot harder but gas mileage was real bad.
3.42 gears
I can't stress enough to use ZDDP oil additive if you run a hyd flat tappet. Ask me how I know.
Engine has a ton of torque. It moves the Caprice very well.
