Tri, Tri Again Part IV

Jim Taylor uses anti-seize on the power valve actuator piston before it is placed in the airhorn. The washer part of the actuator assembly creates an interference fit in the airhorn, but to make sure it stays in place, Jim stakes it with a flathead screwdriver and a hammer.

Here is the assembled airhorn, with the needle and seat, float, pin, accelerator pump, linkage, and the gasket all installed. Once Jim places the airhorn onto the carb body, he uses 30-weight oil on the threads of the original eight screws before they are installed.

This is the complete choke assembly, left to right, top to bottom: choke housing, baffle plate (heat shield), choke cover, heat element assembly, high idle cam linkage, airhorn-to-choke gasket, choke plate and rod assembly.

Taylor assembles the unit without the choke blade, test-fits it into the carb, then installs the choke blade with the same peening technique on the attaching screws as used in Part II.

Jim mounts the previously assembled center and end carbs and starts running the aluminum fuel lines. The lines have to snake through linkages, etc., and a little tweaking is necessary to get the lines aligned perfectly with the inlet fittings. To get them lined up, it's best to leave the carbs loose because it's easier to get the threads started. If you have the carbs bolted down already, you will strain your fingers if they aren't lining up correctly.

Jim test-fits the lines--it takes a few minutes to get them all perfect, but after some minor adjustments he threads them into place and checks for any clearance issues.

Liquid Teflon is used on the brass inlet fitting. Taylor believes it prevents deterioration of the pot metal airhorn threads.

Taylor didn't have an original Ram Air pan for us to photograph, but he did have a repro Ames 1966 steel pan with the seal, part No. N174CL. The only difference between the two years was that the 1965's pan utilized a smaller center carb hole than that of the '66 unit. Ames sells reproductions in both steel and fiberglass, and the '65 part number is N174BL. Contrary to popular belief, no air is actually rammed into the engine with this piece since the scoop openings are in the boundry layer, which is an area of unstable air that exists up to 1 1/2 inches above the hood surface. So the benefit is actually cooler (ambient) outside air, rather than hot underhood air.

This original Pontiac service bulletin, dated January 31, 1966, announces the availability of the "Air Scoop Package", part number 984741, for 1966 GTOs equipped with Tri-Power. It lists the original 1965 part number of 984716 for that model year's Ram Air system and explains why the "shroud assembly" for '66 will not work with the 1965 engine.

Here are the available air filters for a Tri-Power setup. The #A220C AC Delco replacement...

...the original foam unit (with the part number, A193C, inscribed into the material)...

...and a #A052B6 K&N. "For filtering and flow, the choice today would obviously be the K&N unit," Taylor opines.

Passengers Side: The heat riser tube (the left-hand, vertical tube) brings hot air to the choke dial spring. All of the original mild steel tubes are rusted out by now, but Steve Ames sells reproduction kits under part No. N147. Our air intake tube (the right vertical tube) is part of a loop that connects to a fixed tube in the exhaust crossover section of the manifold. The air gets heated and is pulled by vacuum into the original choke housing (with the dial coming from Ames) and expands the choke dial spring, which opens the choke plate. These mild steel tubes are also part of Ames' N147 kit. The stainless steel loop inside the manifold (center, bottom) transfers hot air to the choke housing. Ames has just reproduced this piece, listed under part No. N147B. A long section of the 3-piece, 5/16-inch aluminum fuel line kit, Ames part number N120, goes from the distribution block mounted on the front carb to the rear carb inlet fitting. Another section of the Ames 5/16-inch aluminum fuel line kit goes from the front of the distribution block to the middle carburetor inlet fitting. The front carb actuator rod carries Ames part No. N153, and the clips that secure the rod are included. A replacement metal PCV connector (sans hose in this photo) is from Ames, part No. N210M. This connector is also available in nylon (which Ames sells under part No. N210), but for longevity's sake, Trips should be built with a metal unit.

Front: The 3/8-inch aluminum fuel feed line from the fuel filter to the distribution block is the final piece of the Ames fuel line kit. Also used here is a replacement coolant temp sender, Ames part No. M192 (used with Rally gauges). The carb ID tags are Ames reproductions, part No. N138C for manual trans applications. Carb air filter gaskets carry two Ames part numbers: for the smaller center carb, N107. For the two larger end carbs, N108. The '65 Tri-Power thermostat housing is a reproduction (part No. N140A).

Drivers Side: On the drivers side we see the front carb accelerator linkage, which works the throttle pump. This is an original piece that has been cleaned up and reused. The Tri-Power mechanical accelerator linkage replacement kit from Ames is part No. N151. Originals aren't prone to many problems, but "they are usually just missing", Jim laments. Partially obscured is the center carb's accelerator pump linkage, which is also an original that was cleaned up and reinstalled. An original atmospheric idle vent valve is checked for operation and adjustment, then set up according to GM service manual specs. These pieces usually don't stray far from Trips, so chances are good that you can salvage a few. The high-idle cam actuator (choke) is the flat piece seen on the right side of the center carb. This is an original part that is usually on the carbs, and the design is the same from "the beginning" says Taylor, "right up to 1965", so you shouldn't have trouble finding them. The rear carb's accelerator pump linkage is also an original that has been cleaned up. If you are missing these linkages, Ames has the front rods (part No. N153AM), the rear rods (part No. N153AN) and the center rods (part No. N153DA) for sale. All of the necessary clips for these rods come in the kits, as well. Tri-Power carb mounting studs and nuts, best seen here on the front and rear carbs, come as a kit, too--part No. N187L is on hand at Ames, and you will need three kits to complete the project (washers aren't included--Taylor likes to use 5/16-inch flat stainless steel washers). For the special stud that provided vacuum, you will need to order part No. N188G. The original throttle cable bracket retains an Ames replacement yellow return spring (part No. N150G). Jim usually has a hard time finding original brackets, which is where Ames' excellent N147L reproduction part comes in.

Top: The air filter mounting studs come as a replacement set, Ames part No. N138. There are two different sets: one to mount the air filters, and another set with longer studs to mount air filters when using the Ram Air pan (N137F). Trips wing nuts can be had in sets of three by ordering part No. N137. The chrome air cleaner lids are an exact reproduction from Ames, part No. N106.