Sure, you've seen articles on gold standard engine detailing and you have probably read features on defensive engine detailing to make your artful efforts last longer. But have you ever seen a tech feature on a Pontiac engine that combines the two? Well, now you will. We have combined engine builder Jim Taylor's best tricks for longevity with a nearly factory correct look, in the detailing of this 1966 Tri-Power 389. The result is a GTO engine that to anyone but a true aficionado looks 100 percent factory stock, but can be run and driven on the street without many of the paint, plating and preservation of bare metal parts worries that are normally associated with a show car. This particular engine is destined to return to Eric Lombardo's 1966 GTO engine bay. His is a rare piece that was fitted with Ram Air in 1966.
Jim Taylor Engine Service, owned and operated by HPP contributor Jim Taylor, has participated in many HPP tech stories in the past where power was the ultimate goal. This story is a change of pace to show you how to create and maintain that stock look for your Pontiac engine. So follow along as we take a trip around the outside of the legendary 1966 Tri-Power 389.
Which side does the oil fill go on? It's an age-old question for 1964-66 GTO owners and at every show there will be a line of Goats with half of them on the right and half on the left, and some with the valve covers mounted upside down. Using factory photos from the 1965 and 1966 press and technical literature, we placed the oil fill on the passenger's side despite the fact the many restoration sources state the opposite. Jim stresses that ease of service is as important as a proper look. To that end, he greased the threads of all of the external engine bolts where needed to facilitate future disassembly, should the owner decide to make upgrades.
This trio of Rochester 2-barrel carbs was rebuilt by Taylor using kits from Ames Performance Engineering. For the cosmetic restoration, Jim used Eastwood's carb renew to get the gold tone on the bodies and the bases were painted black. According to Jim, the carb renew seems to last as long as the factory anodizing does and it's a lot cheaper. As an added benefit, with the Carb Renew the customer can then perform touch-ups on blemishes that may surface over time relatively easily, as opposed to having to incur the cost and disassembly time to have the carbs reanodized. The hard-to-find bowl vent shown here on the center carb is an original piece. It's made from stainless steel and was simply cleaned up and reused. Its rubber stopper is included in the carb rebuild kit. The choke pull-off, seen on the passenger's side, is a reproduction piece from Ames. It is very close to the stock piece but does not feature the RP logo on the side for Rochester Products like the original piece did. Though the fuel hose routing is correct and is the correct 3/8-inch diameter, the hose itself is a NAPA part. NAPA has been removed with paint thinner, but the 3/8 SAE and Made in the USA remains. Jim uses this hose because, while not correct, it is safe and of known origin. Repro carb tags are from Ames and they are close to but not identical to the originals as these are silver and the originals were gold, according to Taylor. Carb air horn screws are original black phosphate plated. They were just cleaned and reused. The hardware used to attach the carbs to the intake is cad-plated to thwart rust, so the look is not correct per se. The fuel filter bracket is a reproduction item that is very close to the original but it features a different part number. Also, a reproduction item from Ames that is very close to factory appearance is the wire loom for the alternator and temp sending unit wire that's located at the top valve cover rail.
The repro air cleaner tops are chrome-plated steel and are very close to the originals in design and appearance. Filters are AC A220C replacements for the Tri-Power. These paper elements differ quite a bit from the originals, which use a circular wire mesh that is wrapped with black foam rubber with an embossed A193C logo. The reason for the change is twofold. First, the originals are very restrictive, which would hurt this internally modified engine even more than a stocker. Second, the new air filters have been used as replacements for years and can be had at most any auto parts store. Filter bases are also reproduction pieces that closely resemble, but are not identical to, the originals. One large difference, however, is that the factory bases are made from steel and these repop bases are aluminum. They are delivered painted semi-gloss black with no preparation done to the base metal prior to painting. As such, the paint flakes off almost immediately at the touch of a hand when they're installed. We let the blemishes remain for these photos, as an example. These chips that you see are a result of simply removing the bases from the box and mounting them on the engine. Obviously, to make the finish last, the paint must be stripped and the aluminum pieces must be scuffed, cleaned and repainted with a quality product. For added insurance you can even prime the pieces with zinc primer and then paint with semi-gloss black paint, as was done after the photo shoot. Carburetor linkage is mechanical and is a compilation of cleaned up stock and reproduction parts from Ames. The look is correct. Our throttle cable mount is original on this engine, as you can see with its part number stamped on it and the special bolt and castleated nut to retain the cable bracket. The reproduction item does not have a part number and it uses a squash nut in place of the castleated piece. Note that at the rear of the front carb is a vacuum provision for a power brake booster. The '66 in which this engine will be mounted does not have power brakes so a brass plug is used in the brass fitting. If power brakes were present, a metal tube would run from the junction to a rubber hose and then attach to the booster. The pieces shown are original and were simply cleaned.
On the passenger's side of the Tri-Power unit we see the linkage from the front to the rear carb, which is simply a steel rod. The system works like this: the center carb linkage actuates the rear carb (as seen on the driver's side) and the rear carb linkage (as seen on this side) actuates the front carb. Jim says that it is imperative that the carb linkage be adjusted so that all three carbs hit their full-throttle linkage stops at the same time. 1966 was the first year for the divorced choke system, which placed a choke thermostat housing on the intake manifold, replacing the heat tubes that ran from the intake to the Bakelite-covered thermostat housing, which was mounted on the center carb on previous models. Our choke thermostat housing is factory. The reproduction piece looks nearly identical to the factory piece save the lack of the RP logo and part number. The plated black phosphate screw that holds it down is a factory piece. Note the correct PCV hose routing. For 1966, the water neck is an exclusive. Ours, shown here, is a reproduction. The fuel lines are repros from Ames and look, stock.
With the throttle cable bracket removed, we get a better look at the center and rear carb linkage. As was the case with the carb bodies, gold anodizing has been replaced with Eastwood's Carb Renew. Routing of the vacuum lines is correct. Between the center and rear carburetor is a vacuum tee. The hoses are new and the tee is a reproduction metal unit that replaces the factory plastic piece, which was less than bulletproof. Reproduction plastic tees are available as well but Jim preferred the strength of the metal tee.
Eagle-eyed observers will note a slight difference in the fuel lines from a traditional Tri-Power setup in that there is a change in the method by which the fuel is delivered from the fuel pump to the carb lines. Instead of a short turn of metal fuel line exiting the top of the junction block, a fuel fitting is used, as shown. This is needed on models that are fitted with ram air pans because the gentle curve of the metal line hits the pan. Most sources indicate that when you are installing the ram air fitting, the junction block should be turned over so that the fuel fitting faces downward. Jim Taylor disagrees. He reasons that these systems were designed to have the fuel enter from the top. If you turn the junction block down, then there would be no need to change from the non Ram Air hard line to this fitting. So he has installed the fitting in the upward position and the factory pan fits perfectly.
Another age-old problem with Pontiacs is the burning and discoloration of the engine paint on the exhaust ports and the heat stove adjacent to the carburetor on the intake manifold. Taylor says one problem is that many owners believe that more paint is more protection when, in reality, the opposite is true. With a thick coat of paint, according to Jim, a membrane is formed that traps the heat in the inner layers and then just burns through the outer layers. His secret for reducing burning in these areas is to first apply two light coats of Krylon's Rust Tough Enamel Primer after cleaning the block, heads and intake thoroughly. Once the primer has dried completely, Jim paints the engine with Plasti-Kote engine enamel custom color 227 Pontiac Blue Metallic. While the rest of the block and heads are painted with multiple thin coats as per the instructions, the high heat areas are simply dusted with color until a uniform look is achieved. The thinner layer of paint allows heat to dissipate through it and the Silver Blue hue that we all know and love lasts a lot longer than when heavy coats are applied. And even though the Krylon is not listed as a high heat primer, it still works well, according to Taylor.
This vacuum stud located on the passenger's side of the rear carb is a hard-to-find item. Its purpose was to provide vacuum to the A/C vacuum diaphragm on cars so equipped. However, it was installed on all Tri-Power units. Also visible on this page is the heavy-duty return spring for the secondary carb's throttle blades. Jim says that these will weaken with age and should be replaced during the rebuild.
Though it seems odd even in the '60s, from the fuel pump to the fuel filter no metal lines were used on the Tri-Power. To avoid having the loose rubber hose contact moving parts, a small clamp held it close to the engine block. Jim replaced the stock clamp with the rubber-coated piece shown here. An AC replacement fuel pump looks the same as stock in configuration and color and it is retained to the block with the factory 12-point bolts. Pulleys are the factory pieces that were stripped and painted with Krylon Rust Tough semi-flat black paint. Natural was the color of the day for the fan and fan clutch, according to the 1966 sales catalog. Natural, however, doesn't last very long in the real world, so dull aluminum paint was applied to retain the appearance for the long haul. A stud on the head bolt is for the battery ground, original nuts and bolts are used on the water pump and the correct long bolt and contoured washer is used to draw the intake to the water pump housing. The block-off plate shown dates back to the vacuum secondary actuated-Tri-Power units, which used this port to house a thermostatically controlled vacuum switch. The reproduction fuel filter, while sporting an AC logo and part number, is not an exact replica of the original in size or shape. And it does not fit as tightly in the bracket, which is also reproduction, as the factory piece would. The temperature-sending unit at the front of the intake is an AC replacement that looks just like the original AC piece.
The factory timing tab for 1966 is marked at -4, 0 and +6. Jim scribed a line in the balancer at 34* to make setting total timing easier. The balancer was rebuilt and rerubbered, which Taylor says is imperative to engine longevity. The balancer is painted engine color.
The center head bolt is exclusive to 1966 engines because a rail was added in this year to facilitate the use of air pumps for emissions controls, which were required on California cars. With the rail in place, you could not get a socket on a traditional bolt head, hence the need for this one. This was the first year for this type of oil dipstick, as well. In years prior, the dipstick had its upper tube bolted to the valve cover. The valve cover has a lip at the bottom to stop the gasket from pushing out. And the lip at the top turns up instead of down, so don't put the covers on upside down. Spark plug wire routing is correct.
The exhaust manifolds have been treated to Eastwood Cast Iron paint to retain an as-cast appearance, since the manifolds were originally delivered bare. They are retained by stainless steel, grade 8 bolts with a flat washer and a lock washer. This is not correct, as the manifolds originally employed steel bolts and washers with metal tabs that had to be bent around the bolt heads once they were tightened. Jim prefers his method because the stainless bolts won't rust, the lock washers will keep the bolts tight and the owner can retighten the manifold bolts at any time without worrying about breaking off the tabs on the factory style washers.
To light the fire, Jim installed reproduction Packard TVRS ignition wires. These are date coded 3Q 65, which means the third quarter of 1965. Jim explained that most times the wires were only made in the second and the fourth quarter but Pontiac production was so high that a third quarter run was done by Packard to fill the demand. Since the wire date codes can run up to a year behind vehicle production, Jim chose these wires based on the GTO's build date. Here, the wires are held by a rubber coated reproduction bracket that is bolted to the back of the head using a factory bolt and lock washer. The plugs are R45S AC and the stampings on the head are from the machine shop to identify rebuild procedures that were performed.
The cast-iron distributor used in 1966 featured an aluminum wraparound tag with the distributor number and a date code. The distributor is thought to have been installed natural, which would rust in about five minutes. Jim painted this one with Eastwood Cast Iron to retain the as-cast look. The hold down is an original piece and is now painted black and the bolt and washer are stainless steel so they won't rust. The vacuum advance came through natural from the factory--this unit has been polished.
The oil pressure sending unit is a repro and Jim says it looks correct, while the fittings are brass originals that were cleaned. The filter is from Ames as well. Jim warns never to block the oil pressure bypass on a Pontiac engine. He also told us that he uses liquid Teflon on all of the fittings to better seal them. He remembers Pontiac using some sort of sealant but it wasn't Teflon, so this is incorrect in the eyes of a judge but is a safety measure, just the same,for the street driven Pontiac. The appearance of the PCV and vacuum advance routing is correct even if the rubber hoses may not be.