Kenne Bell Standard inlet or Flowzilla inlet?

Couple of things:

If you go KB then get the Flowzilla. It's a pain in the ass to install but worth the effort. The rear passenger side intake bolt will have you cutting, bending, and making tools to get to at it, all the while cussing words that you'd never thought you'd use.

I initially started with the Blowzilla kit (2.2L). The Flowzilla inlet ALONE was worth between 3 and 5 lbs of boost (depending on ambient air temp), all by itself with no other mods. The inlet becomes even more beneficial as you remove other restrictions from the inlet.

The deck surface of the TFS heads are 3/8 in. taller than stock. You're going to have to find yourself a machinist (or you may be one for all I know) to modify the snout bracket to allow for this additional height. With luck, KB still includes the template to modify the bracket with the instructions. If you choose to do this mod in your garage then use your head. Don't blindly follow the template so that you can't reuse the same bracket if you ever go back to a standard height set of heads. I chose to have a machinist slot the holes so that I could use it on either set of heads. I don't regret it. KB used to sell the modified bracket but I don't think they do that anymore.

400 HP an more is not a problem. As for how much boost you'll need to get there... well, that depends on how well your motor breathes. It's a positive displacement blower and boost pressure truly is nothing but a side effect. 10lbs of boost on your motor might get you to 400HP (I've no idea, this is just an example) where 10 lbs on my motor has the blower forcing twice as much air through the motorand well over 600 crank HP. In other words... it's not a fair question to ask. If you were bone stock, it might be a little easier.

Lots of things can effect the outcome. Inlet restrictions are HUGE. Plan on at LEAST an 80mm MAF and a Power Pipe (or equivalent) to get the most out of that inlet (90mm+ would be better).

Either way that blower has the power potential to split your Ford block right down the middle.... and to be honest... for the money and complete lack of support from KB concerning an after-cooler for pushrod motors??? I'd think real hard about spending that money on a Hellion Turbo kit instead of a KB.

I've had a LOT of fun with mine and still like it a lot but I'll tell ya... those butt-nuggets should have come out with an after-cooler for our cars more than 10 years ago!!! Point = turbo / KB = 0

Where I'm at now? A built motor and the limits of the blower.