Because the log heads flow so poorly in comparson to the 2v's and CI heads, you can't really overcam a turbo 200. But you can overcarb it, so I'd personally not bother with the PVCR changes
Saw the
http://www.hangar18fabrication.com/blowthru.html. It's up to you. I'd just boost reference the power valve and be done with it, like Does10s did.
But lean out is the enemy of any carb turbo, so you'll have to figure it out yourself.
There are 4bbl to 2-bbl adaptors about for fitting Rochester and Holley 2-bbls to the stock Rochester 4M, or Holley 4175 or 4160 Holley 4-bbl. There is a dedicated 2-bbl oval track class that allows the 4-bbl intake to be used. The adaptor can be flipped over. We used to use them when putting 650 double pumper 4-bbls on 2-bbl Straight Six Valiants (1970-1982 245/265 Hemis). They work really well, but you can't make it a 4bbl into 2-bbl into 1-bbl adaptor on our I6's because there isn't enough carb area. direct mount a 2-bbl adaptor plate, and ledge it out for the 4-bbl. The primaries are far away to the right of the car, and when the secondaries open, they will be right over the direct mount 2-bbl and there will be less lean out. If you use the old LeMans float bowls, the carb will pacakage in the engine bay of a RoundCon just fine.
4bbls run nicer with bigger duration cams, and the mechanical or vac secs can be run to enrich things if needs be. Or a 660 with 1:1 linkage, the old 4224, is a good bit of kit. A large cam likes 4-bbl carbs, probably why Holley and Rochester invented them in the 50's in the first place.
