I’ve been thinking about a SUBY like Marty’s or something like this
If that CB engine is really within your budget, you want a 2.5 Suby as installed by Carey Hines. Like the man said: 180 hp (probably a little more), same torque at something useable like 3000 rpm, and it just works.
You want authenticity? Buy a Porsche; these are something else entirely and that's just that. If you're worried about weight, don't. The N/A Suby is only 40 pounds or so more than a dressed, hot-rodded VW Bug engine as cast by Autolinea, and the 20 extra pounds of radiator and hose go mostly up front, leaving you with a weight distribution that's pretty much what it was with the Type 1. I believe a Type IV engine is heavier than the Suby.
To my lights, the only argument for putting a Type 1 in these cars involves an appeal to atavism, a love of nostalgia, a fetish for oil leaks and—perhaps—a desire to dress said engine to look rather convincingly like the P-car motor it's pretending to be. I'm that guy; I get off on that stupid oil filter can thingie the old Porsches had in back of the fan shroud.* But you?
Just your screen-shotting the turbo'd CB engine demonstrates that you give not a whit for "authentic 356 engine looks." You want power. Japanese junk yards are overflowing with it. Hear the call.
Or at least just consider what I call The Swap Test:
You will see guys swapping out Type 1 engines for Subarus. You will not see the opposite.
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*I am the guy who has dressed a Type 1 engine with the accoutrements of a Type 547 Four Cam, for reasons that can be neither understood nor appreciated by anyone sane. And I am also that guy who personally shoehorned a Suby mill into the restricted confines of a TD replica engine bay, where nigh God nor Beast ever intended it to be. So you can see I swing both ways, in swapping terms.