[My427stang]

If the heads really have been pocket ported well (and has headers), the car can make some good power, however the limiting factor in a stock 390 head is the exhaust bowl and if it wasnt done, it'll steel FEEL fast, but it wont really boogie

If it were me, I'd upgrade the cam to a modern performance grind, add headers, and make sure the heads are really bowl ported, not just big valves

 

[My427stang]

If thats the case, I'd still go with a better cam, either a Comp 265DEH or a 270H grind, the 390GT/428 cams was limited to the high 400's in lift and has a very wide LSA, it would work, but a modern cam is like free power

Still ask him how much he plans to work the bowls and which head casting number he plans to use, it will make a difference, both in power potential and what you need for headers/manifolds

We can easily spec you out a motor that will make you giggle LOL on the cheap too, but what he is proposing is only 1/2 way there and mostly because of lack of specifics

 

[My427stang]

We are doing a 390 stroker right now

.030 over 390, with 4.25 stroke for 445 cid, a set of heavily ported iron heads an RPM intake and a 950 Holley

Should be an easy 500 hp motor with a hp peak under 6000 rpm

All in all for parts and machine work, not my labor, its well under 5000 dollars and much closer to 4000. SHould be a bad mamma-jamma

Thats including conversion to Erson roller rockers and solid flat tappet cam