{{ ok guys how much hp will it make }}

If the carbs are jetted right for the intake, you will have a engine that will be a torque monster.
It all depends on the head work, but i think 490 horse is a good guess.
The same set up in a 360 would be good for 450.
I think 40 cubes more is worth 40 horse.
The torque will be over 500 foot pounds.
A 408 is a very big engine and with a stock head should make a lot of torque.
Did i say torque???????:clock: time will tell. Good Luck.