Hello, from Alaska. Nice looking concept (gotta love a photochop
).
I am by no means a 250 or even an inline 6 guru. But in other engine types (both inline and V) I have found that for the driving you describe, forged pistons aren't what you want. If you could get a set of hypereutectics, with the appropriate compression height, and have your machinist fit them to the bore appropriately you will be happier with the performance overall. I would definitely change out a full race cam for something more streetable for the driving you describe.
I can't help you for what bellhousing to use for the T56. Be careful with the late model flywheel, it is probably for an external balance SBC (the later model ones were, had a bolt pattern change at the crank circa 1986 too).
For a clutch, I have a Hays 95-201 set in my Model A. It is a full metallic button type disc, with a 2750Lb pressure plate. It is amazingly easy to push the pedal down (you can push it to the floor with your hand). Dad drove it recently, he couldn't say enough about how light the pedal was, he has a bum left knee. It modulates well too, it's not the grabby nasty bear trap I had come to expect from other brands. I know that set doesn't match you trans (it fits a '92 Mustang W/ a T-5) but they have an equivalent for either the pull type, or the more traditional push type. I found they were cheaper than some other brands too.
For side drafts, I have been looking at putting together a set of SU's, however for the racier look you might try the carbs off a Harley 1200 (use 3 of them). You will be slightly larger per carb than they were set for originally, but people have recommended them to me as they are usually cheap, since the Harley drivers take them off to 'upgrade'.
I posted a similar question (on the carbs anyway) on this forum under:
Inliners International Bulletin Board » Engines » SU's?
It was on page 2 last I saw (couldn't get the actual address to show up, or I would have linked to it).
