[DeTomaso] Brake booster vacuum

[B. Seib]

Nice to have you back on the list lately Guy.

No time machine required.
I still have my original 1972 700+cfm Motorcraft 4300D spreadbore carb in
use and the stock manifold and air cleaner, etc.
(shock, awe, disgust from all present)

The little port on the side of the large power brake manifold fitting is for
the servos on the air cleaner(which close the hot air stove and the aux air
inlet valves). The vacuum advance is supplied by ported vacuum from the base
of the factory carb.
The other little single port manifold plug is on the right side near the
front of the intake and it is to supply manifold vacuum to the PVS/TVS valve
that allows/denies the distributor direct manifold vacuum instead of ported
vacuum depending on coolant temp. Most of this is explained in Bulletin 8-61
page 4 of the TSBs.

I am surprised how well the stock spreadbore carb runs and performs with a
Crane cam having 70 degrees of overlap. It's no longer running on Mr.
Nader's fuel&ignition calibration settings, but with a little fiddling it
really works well. Much better than a Holley 650. I don't use the PVS/TVS
thingy on my car. It was very frustrating to build one 4300D carb that
didn't leak and worked well from the remains of four of them though....If
you're stubborn, you have to pay. I sure wish a Quadrajet would bolt on the
Ford manifolds!

Barry

----------------------------------------------------------------------------
----
Guido deTomaso guido_detomaso at prodigy.net
Fri Oct 12 16:52:15 CDT 2012

I'm guessing that had to be for the retard side of the push-pull distributor
and/or the fresh air flap on the aircleaner.  Suppose we'll never know
without building a time machine.  Surprised I can't find a vacuum hose
routing
diagram here at the compound, that would tell the tale.

GD