Realistically, how much do you imagine this project is going to cost regardless of which engine you choose? have you researched parts/prices etc and come up with an actual budget? I would suggest at least outlining whatever "it" is on paper and looking in to price/availability/viability.
Either way, you ain't getting a rebuilt engine done for under $3,000 including all the surrounding stuff necessary to make it all work together. With that in mind, you'd be a lot closer to reliable performance with the V8, end of story. I don't think we can make it any clearer.
Think about it - any boosted engine is gonna need fairly good ring seal, no matter what the performance goal. That's at least a re-ring and hone job. You also want the valves to seal so that's a valve job on the head and probably new valves, cam, springs, lifters, gaskets, blah blah blah. Not much aftermarket support for the Slant so again, on your own.
With a decent rebuild job and really basic bolt ons, the 360 will easily make 300 hp. Standard 360 rebuild parts are REALLY cheap, like almost SBC cheap but not quite. I'd like to know the cost difference between a basic rebuild for these two engines, all machine work being equal. Be a good comparison.
Read
here for some basic combos. Study what parts they are using for each and look at the cost.
We're telling you to go with the V8 for a reason, you will get BETTER VALUE FOR YOUR MONEY with the 360 or even a roller 318 for that matter. Seriously, forget the Slant. That's for guys who've been messing with them for years and are trying to prove a point. Again, not worth it in every respect. You will not look back with the 360.