I'm still using a large body starter with my old Blackjack headers. I've had to loosen the flanges the last time I had to replace the starter. If I ever need to replace it again, I would go with a GM truck mini starter. The clearance is also beneficial as far as minimizing heat soak. Fortunately, even with my larger starter, I never had a heat soak issue...nor did I ever need to install a heat shield of any kind.
I used flowtech headers with a big old style gm starter fit fine with my sbc. Didn't have to loosen the header any when removing or installing the starter. The best factory mini starter I've used is either for a Corvette or camaro with a lt1 engine from the mid 90's.