Whats the difference ? 4150 question !

Old thread new idea, I am wondering if anyone makes a spacer between the main body & throttle plate. I'd like to make an 850 out of my 830 hp. Then tune it to work for my application, but maybe it won't be enough carb
Goal is low 10.00s ! Engine is 470, trickflow 240s 11.8:1, good oiling system. For now [email protected] howard's sft. 1.6 hs rockers & trickflow intake.
The cam & carb maybe a little small for the goal but eventually I'll go solid roller & see where I'm at with the carb.
Thanks !
Nevermind I found blp makes a spacer.