The Edelbrock carb is a licensed copy of the old Carters, but they have an
interesting difference. There is a 1/4" pipe threaded female inlet in the
back of the Carb at the very same spot that R-1s and R-2s have the threads
for the PCV valve. Only the instructions with the Edelbrock say this vacuum
source is for power brakes. The PCV connection is on the front and instead of
being a threaded female connection, it has a pressed in piece of steel tubing
for the type of PCV valve that connects to a neoprene rubber hose. (like an
inline fuel filter). Well, I wanted to know if I could screw in an R-1/R-2
PCV valve in the threaded hole intended for the power brake vacuum source,
and just cap the vacuum source for the PCV valve on the front side.

I called the Edelbrock Tech Hotline today with that question.  In a minute 
he came back with this answer. You can use the brake vacuum source connection 
if you want to, but it you do, the two rear (spark) plugs on each side will 
get fouled with oil more quickly. The reason the Edelbrock puts the PCV on 
the front side is that the oil fumes and mist are in the constant fuel/air 
stream of the primaries, and this mixes that oil more or less equally at all 
times going to all cylinders where it is burned.

But when the PCV valve is connected at the back of the carb, most of the oily
mist and fumes goes into the 2 rear cylinders on each side because the
secondaries only open at full throttle (so the oily mist only gets mixed
thoroughly into the air/fuel mixture going to all cylinders at full
throttle). This in turn causes the plugs in those cylinders to foul more
quickly.

That's why the rear plugs on a Studebaker R-1 or R-2 foul more quickly than 
the front ones. The PCV valve on the AFB carbs of that era were at the back 
of the carb under the secondaries. I know I have heard others comment on this 
phenomenon also, but with no explanation. Could this be the explanation and 
the reason why plugs have to be changed every 2,000-4,000 miles on the R-1s 
and R-2s?

sgundry@aol.com  August 2000