As long as the throttle shafts are not too loose you should not loose too much boost pressure.
You can purchase an enclosure for a carb that encloses the whole carb.
Paxton had them. I think Vortec has them & other company's.
With the carb completly enclosed you do not need to worry about the throttle shafts leaking & other leaks.
You still need the plastic floats though.
http://www.vortechsuperchargers.com/products/yourcar/univ_carb_encl.html Paxton Universal Carburetor Enclosure without Fuel Lines (satin)
All
$650
http://www.superchargersonline.com/product_listing_2M.asp?Cat2=accessories_carbenclosure http://www.superchargersonline.com/product_detail.asp?PartNumber=V8M205-012
