Can I get a /6 in the 7's?

Swap a v8. This is coming from a slant guy.

Do you know how to modify and tune a blow thru carb?
How long do you want to spend tuning?
Do you like dealing with an engine that they dont make hardly any parts for?
Take a look at the number of fast /6s compared to the number of fast v8s. There is a reason for why people do things.
The slant isn't some performance secret. If you build a slant, its because you, for some reason, either LOVE the engine, or you want to be different so bad that you're willing to throw buckets of money at it.
Another thing to look at, look at how many people can tell you FROM EXPERIENCE how to build a fast slant.
How many people own slants that are actually sub-12 second cars?
How many people have turbo slants and don't constantly have problems with them?
Go find out what it takes to make a slant faster than a 318-2

Sorry to be Realistic Ronnie over here, I just felt the views needed to be equalized lol

Oh, and according to my calculations, if your car was stripped down to 2600lbs, and you made a true 300@the crank, you MIGHT just make it, everything else being absolutely perfect.