I've always liked multiple carburetors. My first car in 1963 was a '55
Pontiac. By 1964 it had a 1958 motor (370 cubic inches) with a tripower
sitting on top. The truth is, I never did get that tripower working correctly.
In 1986 I restored a 1966 GTO and, of course, put a tripower on it.
I began buying, selling, and restoring these set-ups in 1987. I am very
familiar with the '64-'65-'66 tripowers; somewhat knowledgeable of '60-'63,
which are very similar.
MYTH Tripowers are always problematic and hard to keep in tune.
FACT I don't know where this started, but you hear it often repeated
at car shows and swap meets. Think about it--a tripower is made up of
3 very simple 2-barrel carbs. The center carb supplies the fuel at all
times, except under full throttle. The end carbs are extremely simple.
They have no idle circuits, no choke.
I do believe that even when these units were new they freightened
many merchanics and owners. I remember taking my '55 Pontiac to several
garages back in '64-'65. They wouldn't touch it! The truth is, they
didn't know about them and didn't care to learn. My current car, a '65
GTO, has a '66 tripower that has been on 5 years with virtually no problems--none.
MYTH The carburetors have to be "calibrated."
FACT What? Maybe a set of Weber side-drafts. I've got an original
motor manual from GM--no mention of calibration. The only adjustment
on end carbs is the float, and I suppose the rod to the accelerator
pump. You adjust the center carb exactly as if the car had a 2 barrel.
MYTH Tripower cars are prone to catching on fire.
FACT Well, there is some basis for this. Notice that Pontiac
(as well as Oldsmobile and Cadillac) used metal fuel lines. When owners
rebuilt the carbs, these had to be disassembled. There are many opportunities
for leaks. On a '64-'65-'66 Tripower, I count 8 sites for possible leaks,
versus 2 for a 4 barrel. I believe many owners were unwilling to go
to the dealer to purchase new lines and fittings when needed. So...here
come rubber lines and chrome fuel blocks. BAD IDEA!!!
Most tripowers I buy at swap meets or from individuals have rubber
lines or evidence of them. Don't ever use rubber ruel lines on a tripower.
The reason there are more bare intake manifolds then carbs is due
to the fact that intakes survive fires, carbs don't.
MYTH I can take my tripower carbs to the local carb rebuilder,
he can rebuild them, he said so.
FACT Don't let anyone who isn't familiar with these carbs touch
them!! Yes, they can rebuild them and set the floats. But, unless they
specialize in Pontiac tripowers, they won't know if your carbs are right
in the first place. They can't offer you any advice.
Did you know that each major section of the carburator (air born/float
bowl/base plate) is different? There is a difference between front and
rear air horns. E-Mail me and I'll tell you. There is a difference between
the center sections (float bowls) of the front and rear carbs, usually.
They wouldn't know this. The baseplates are different, too.
Yes, internally the carbs are simple. But, when you put them on the
car and find your reproduction Year One linkage won't fit-they can't
help. Neither can Year One since the linkage isn't the problem. Don't
waste your money on a local carb rebuilder who isn't very famliar with
Pontiac tripowers.
MYTH The tripower isn't really much better than the 4 barrel
for performance.
FACT The '64 Pontiac 389, 4 barrel, had 325 HP -- the tripower,
348. In '65, the tripower 389 was rated at 360 HP. Pontiac discontinued
the tripower in 1967 for 2 reasons that I am aware of. Primarily, GM
came out with an edict that from '67 on, the only multiple carb car
would be the Corvette. And, the Quadrijet, first introduced on the 1966
OHC 6 flowed 750 cfm, vs 550cfm for the previous 4 barrell, the Carter
AFB. For those never to the hobby, the AFB (aluminum 4 barrel) is now
copied by Edelbrocks 4 barrel. The famous 409 had a pair of them. Very
nice. Remember I like multiple carbs.
My '65 GTO--421, tripower, automatic--turned a 12.7 quarter mile at
108 mph the second time out. I drove it 200 miles to the track and home.
For those planning to run in the 11s, the tripower isn't for you. But,
a tripower properly jetted can supply adequate fuel for most street
driven cars. I have never seen accurate firutes on the CFM ratings on
65-66 tripowers. But, the figures I have seen are in the 700 to 800
CFM range. On my car I did remove the casting flash in the venturi and
gasket matched the intake. Otherwise, the unit is completely stock.
I don't include air cleaners, but can direct you to a source for new
ones. I have some used sets for sale, also.
I am always searching for tripower carbs and '65, '66 intakes.
I may be able to repair and/or rebuild your tripower.