The carb duties will be handled by a 1966 Tripower setup. It is completely rebuilt to mostly stock specs. They had # 62 jets in the center, and #69's in the ends. I ran it like this and it ran lean. I installed #69's in the center and #73's in the ends and it is much better. Once I am driving the car, I will fine tune them some more. All three carbs have been cleaned and rebuilt. The throttle shaft on the center carb was worn beyond use, so it has been replaced with a repro one from Ames. I found out an interesting tidbit about '66 Tripower center carbs........ Cars that were equipped with A/C had a different throttle shaft (on the center carb) than those that were non A/C equipped! The A/C version is about 1/8" longer, and the throttle plate screw holes wont line up! I found this out after I ordered a repro shaft from Ames, (using a 4 year old catalog!) and found it didn't fit!!!!!! I first thought they sent me one for a '65 or earlier carb (which are smaller.) by mistake. After checking the new catalog, I found out that the A/C one was different, and exchanged it for the proper one. The folks at Ames were very helpful, as usual! If any of you reading this know the reason for the different length shafts, please Email me!
In my opinion, there has never been a cooler factory induction system than Tripower (OK, dual quads are pretty cool too!)! Nothing sounds better and it looks pretty neat too! Pontiac used it on their top performers from 1957 till mid '66, when GM banned it's use on all but the Corvette. Olds used it on their 442 for half of the '66 model year as well. There are minor differences between the model years, but operation is essentially the same. The system consists of 3 Rochester 2G carbs, mounted on a cast iron manifold. One of the biggest myths surrounding the tripower system is that they are difficult to synchronize. This is a silly assumption, because there is nothing to synchronize! The only adjustment needed is to insure that all of the throttle plates are wide open at the same time. In the Pontiac system, the end carbs are only used as secondaries under heavy throttle conditions. The engine starts and runs on the center carb only, until the pedal is pushed to a certain point, at which point the secondaries are actuated. The end carbs contain no choke system, no power valve or idle circuits. They stay completely closed until actuated. Many cars originally equipped with tripower had vacuum operated secondary carbs, which was a troublesome system even when new. There was a mechanical system that was commonly used to replace the vacuum setup. Operable vacuum setups are pretty rare today, as most owners replaced them with the superior mechanical setup. Mine has the mechanical secondaries. The 2 G carbs are a study in simplicity! As I mentioned before, there are no idle, choke or power valves in the end carbs. The only adjustment needed on these carbs are float drop and level. Factory float levels are 21/32" on the end carbs. It is common practice to set them a bit lower than this (mine are set at 23/32"), to insure good sealing of the inlet needle/seat assembly. Due to the fact that these carbs only operate under higher throttle settings, it is very important to make sure that the throttle bodies don't leak air when closed, otherwise you'll have a vacuum leak, and they will drip fuel into the bore at part throttle. These carbs use special thick throttle plates to help seal. They can be a bit of a pain to get to seal, but well worth the effort (I spent several hours aligning mine so there was no daylight around the plates!). Another common problem with tripower setups is fuel leaking from the bowl cover gasket. This is caused by several reasons. The main focal point of this problem is the inlet needle valve. Either it is leaking due to poor seal or too much fuel pressure. I had this problem due to too much fuel pressure (over 10 psi!). Tripower fuel pressure should be between 4.5 to 6 psi. I installed trick inlet valves from Bart at Hot Rod Carburetion. These valves held closed at 9 psi! They are $7 each and well worth the effort. Much better than the ones in the standard rebuild kits.
New inlet valve (top) is far superior to standard rebuild kit assembly! I installed a Mallory 140 electric pump with 4309 return regulator to insure good inlet valve control and volume. The pictures above are of a holley regulator I used in troubleshooting some fuel pressure problems.
See my Fuel System page for fuel line detail.
'66 Tripower intake on the 400 my car came with...... Gotta love those "Oh So" Moroso valve covers.....
Decent shot of the progressive throttle linkage........Unit runs on the center carb most of the time, the ends are just secondaries.
Original carbs atop restored intake..........
Original, worn, center carb throttle shaft. It was brazed to the linkage...the repro uses a screw.
Repro, non A/C throttle shaft (L), next to original A/C type.
Center Carb Throttle Body with new shaft. New shaft is held on with a screw.
Another view of the new throttle shaft. Center carb.
Progressive linkage. When lever hits the end of the slot, the end carbs start to open, lowering the atmospheric pressure of the neighborhood!
Rear Carb, prior to rebuild.....Condition is representative of all three prior to rebuild.....
Rear carb throttle body prior to cleaning....
Disassembled front carb.....Pretty complex, huh? Note only 2 tubes on the venturi cluster (no idle circuit), as well as lack of power valve and choke parts.
Front carb, cleaned and rebuilt. Note fuel inlet location compared to center carb.....Elongated hole in the throttle lever is correct, to minimize binding.
Front carb, hole in air horn. Anyone know the purpose of this? Most of the ones I see have a tube pressed in, with a cap on it. Accelerator pump rod is in lean hole. Since most guys run them rich, I have changed mine to the inner hole after the pic was taken.
My $.35 solution to the $17.00 "F" PCV fitting!
Correct, 105 degree fuel line fitting, center carb.
It's really starting to look like something! Note height differences in air horns between center to end carbs......
Gotta Love those K&N's!
Repro fiberglass Ram Air pan.