There are few among us who are more die-hard traditionalists than Dick Megugorac, aka Magoo. He bought his first car, a '27 T, in 1944 and has been driving hot rods ever since. Magoo has built everything-T tubs, '32s, chopped Mercs, and almost single handedly made highboy '29s on Deuce rails into an art form during the '70s and '80s. The guy knows what it takes to make a cool car and while he says he's loved every one that has come and gone, he simply describes his latest as "one of the most bitchin' of them all."

Magoo wanted a comfy cruiser, a desire fulfilled by this '63 Chevy Impala. A nice but not over-restored driver, all it needed was a little attitude with an altitude adjustment, and a disc brake upgrade. One of the other things on the to-do list was to add a better selection of gears than the original two-speed Powerglide provides. The obvious solution to that was the installation of a 700-R4 overdrive automatic, well known for its capacity to handle horsepower and excellent gear speed. When combined with the right rear end and tire diameter, this trans can supply stump pulling power with its 3.06:1 first gear and low rpm at cruising velocities with a 0.70:1 overdrive fourth cog.

For the trans Magoo turned to Phoenix Transmission Products. In business for 27 years, Phoenix goes to great lengths to supply transmissions built to suit the customer's specific application and modifications made reflect those requirements. If you're building a cruiser you don't want a transmission that shifts like it was built for drag racing, on the other hand if your car has lots of horsepower and you like banging gears more modifications are necessary. The point is, tell Greg Ducato, owner of Phoenix Transmission, all about your car and what you expect from it and he and his crew will do the rest.

Although 700-R4s are in fact an excellent transmission, they have been known to shift erratically and fail prematurely. However, with a properly built transmission these problems can almost always be traced to improper throttle valve cable adjustment.

The Skinny on TV cable Adjustment from Greg Ducato
The throttle valve, or tv system, for transmission pressure control has been around since GM introduced the Hydramatic transmission before World War II. These early systems connected the accelerator linkage to the transmission and required skill and patience to adjust as well as some special tools. GM continued to use this type of system as did both Ford and Chrysler, until the '70s when a cable system was adopted. The more "modern" variants of this system have been in place since the '76 introduction of the TH-200 transmission. Mercifully, GM did away with the complex linkage and provided a simple cable system, which stayed in use until 1993 when throttle valve controls all together for fully computerized transmissions.

Understanding TV operation
Basically the tv system provides the transmission with pressure increase proportionate to throttle opening. This is done so the transmission will shift smoothly when cruising slowly or gently accelerating and keep the engine at a practical and efficient rpm. When accelerating quickly the engine is in a higher rpm range. Where it makes more power the transmission needs increased pressure to apply the bands and clutches and keep them from slipping.

All GM transmission requiring a tv cable use the same basic range of adjustment. From idle to wide-open throttle, about 1-1/8 inches of cable are pulled, and at wide-open throttle the cable is as tight as it can be without limiting throttle travel. The cable is pulled in a straight line from idle to wide-open throttle to correctly keep transmission line pressure rise in harmony with throttle opening ensuring accurate shift points, shift firmness, and kick-down response. No matter what kind of cable system you are using, you should always verify that you have the correct range of throttle cable travel and that it is as tight as it can be at wide-open throttle. If you have these two parameters in place then you will have successfully adjusted your cable and your transmission will operate as designed.

Due to the very wide variety of carburetor and fuel injection systems it is impossible to design a cable that will work with every model and application. If you are using a Chevrolet-style Quadrajet these have the ideal ratio already designed into the linkage. In fact, nearly any Chevy carb used on a small-block application from the late '60s on up to the late '80s will have the correct linkage. In these instances, you can use the factory-style tv cable and bracketry to install and adjust your cable. These brackets may have been bolted to either the intake or the carb flange and routed the tv cable in a straight line with the attaching point at the carb linkage. If the factory-style linkage cannot be located, Holley sells a nice replacement bracket (PN 20-95) that not only holds a factory-style tv cable but also most GM throttle cables as well. For those with a Holley, Barry Grant, or AFB-style carb from Edelbrock or Carter, things get a little trickier since these do not have the proper geometry for proper tv cable operation and may pull out too much or not enough cable and at the wrong rate. At Phoenix Transmission they have developed individual brackets to correct tv problems with these carbs, allowing simple and precise adjustment without special tools or gauges. These levers simply bolt onto the carb linkage with supplied hardware and give perfect tv geometry. The can be used with stock-style tv cables or aftermarket cables such as those made by Lokar.