Trying to build power....225 step by step help

You be the first. Go get 'em Dano.
300/225=1.33 hp per cube, that's a stinking huge target for any Mopar engine, and takes a wheelbarrowfull of cash.
on a 273, that compares at 363,
a 318 takes 423
a 360 ; 480hp
a 416 stroker; 555hp
On a 440; 586hp

Some/most of these engines have lots of HO heads available.
The slanty does not.
And it doesn't stop with the engine; now you gotta upgrade just about everything else. And what about those tiny wheel wells, with skinny 14s barely fitting in there? What good is 300hp if you need a Super-hi-stall TC to get moving and blow 200hp away on the starting pad? Poof, gone up in tirespin.
IMO,
I think,
You need to;
Lower your expectations,
supercharge it,
or swap it out.