[Mark Simiele]

I was told years ago they are fully interchangeable and work on both years but something is visually different on a 69 unit compared to the 70, anyone know?

[Chiefpontiac]

Mark,

They differ in where the bellows is attached and how it "pulls" on the throttle lever. The '69 bellows is mounted on the engine and attaches to the lever with a chain. The '70 and up bellows is mounted on the fender well by the transducer and uses a cable that attaches to an extended pin on the throttle lever.

I actually need the '69 bellows setup and throttle lever for my '69 Firebird.

[Half-Inch Stud]

68 is fender-mounted.

I JUST got a fender-mounted cruise setup from a 70s-80s Caprice (all I can say for the YEAR is it was a V8 with missing Q-Jet and had the newer fuses).
Certainly different from 1968, yet it is remarkable nicer than the similar year technology from 425CID Caddilac with Q-Jet & telescopic Tilt column, that mounted the Cruise bellows on the Valvecover.

Point is: The 68 cruise needs the speedo cable coupler/tap, while the Caprice Fender unit & Valvecover Caddy unit BOTH use a sensor at the speedo head to catch reflections from a bright reflection off the speedo bell. 2 reflections/turn. That keeps the speedo cable pretty clean.

In all cases there was the simple Cruise lever, rather than the clunky plastic lever. FWIW, I think the modern cruise CONTROLLERs can be an upgrade over the vacuum-break mechanical controller of 68 69 70.

A savy look would be that simple fender-mounted bellows, with the vacuum break hose going to the brake pedal, THEN use the modern GM controller to electrically vector the simple bellows. Result is cleaner speedo cable routing is retained.

[north]

Originally Posted by Chiefpontiac

Mark,

They differ in where the bellows is attached and how it "pulls" on the throttle lever. The '69 bellows is mounted on the engine and attaches to the lever with a chain. The '70 and up bellows is mounted on the fender well by the transducer and uses a cable that attaches to an extended pin on the throttle lever.

I actually need the '69 bellows setup and throttle lever for my '69 Firebird.

Bang on, the 70 system is better than the 69 one but will not look right if you are fussy.

Had cruise on a 69 GP 4 speed car back in 1990 or so (dealer installed 4 gear) and I remember driving to the POCI meet in Clevland on I-90. Had the cruise on at 90 or so and pulled into one of those New York State Thruway pitstops for fuel (a common occurence in a 428HO at 90MPH). Imagine my surprise when the engine decided to maintain the throttle position needed for 90 when I pushed in the clutch (more than enough RPM for mega disintegration of my engine). To save said engine I re-engaged the clutch but could not slow down enough with 465 foot-pounds wanting to go forward so I killed the ignition but it was reving so high it kept running anyhow (dieseling). I Finally got it to stop with a sudden release of the clutch in reverse gear (at too high a speed to admit) that almost lauched us through the windshield (that's what seat belts are for?).

Almost fried the motor and the brakes, nearly wrecked the car, why? That damn criuse chain had come loose and snagged the throttle linkage. luckily the only real damage (other than fried nerves) was that the A/C belt jumped. Being 95 degrees that day we took the time to re-install the belt (a rather unpleaantly warm job) rather than sweat over those nice leather seats.

Never did put that cruise chain back on the car.

[Mark Simiele]

Thats a very scary story John. I have been debating about adding the option but when I hear stuff like this it makes me think twice.

[compsur]

Was noticing this thread and thought it would be a good one to jump on and pick some brains. I am scratching my head as it goes to the differences with regulators used from 67 and on. The parts books and PY online state:
1. Parts book state 67-68 uses 9787978 (Black Decal), shows up in PY online parts lookup.
2. Parts book state 69-72 uses 9797504 (Black Decal) does not show up in PY online parts lookup.
3. Parts book state 73-74 uses 490099 (Not sure about decal color), shows up on PY online parts lookup.

I also found the following Pontiac labeled Regulators for sale on Ebay:
1. 493406 (Blue Decal), not in any Pontiac parts book or PY online.
2. 498586 (Red Decal), not in any Pontiac parts book but does shows up on PY Online stating for 73-75 all.
3. Ames shows a decal for 69 only, with decal part 498556 printed on it, not in any Pontiac parts book or on PY online.

As you can I am thoroughly confused...how do all these parts cross reference, if at all, can the most common one 9797978 be used up to 1975, can 493406 and 498586 be used going back to 1967..what are the differences....each have the 2 wire connection.

Then there are the 3 connectivity regulators but i think they are only applicable to Lincoln, RR, International and Olds also used 3 wire units.

[Half-Inch Stud]

Sparky the GM Cruise Control engineer, kept discovering improvements.

[gto4evr]

Originally Posted by Half-Inch Stud

Sparky the GM Cruise Control engineer, kept discovering improvements.

I think Sparky was a bit slow on the improvements! I always thought my 71's cruise was a bit twitchy and assumed I had an intermittent switch. I figured out on my own it would work when I let go of the button slow but was 50/50 when I'd just hit it quick. I just came across this bulletin while updating my TSB spreadsheet.

[compsur]

Originally Posted by Half-Inch Stud

Sparky the GM Cruise Control engineer, kept discovering improvements.

Exactly....wondering what they were!!