Transistor Ignition - was it originally on my car?

[Joe R.]

My car is a 66 L72. My uncle bought it used in 68 or 69, I'm pretty sure it's an original L72 (427 / 425) car. So, assuming it's a factory L72, transistor ignition (TI) would have been automatically installed in St. Louis. It has been hit in the front at least twice. The TI module sure does not look like it was mounted to the radiator support correctly. It was only held by one bolt (probably because two of the three mounting ears are busted off.) The one bolt that was "holding" it could not be tightened all the way because it interfered with the L bracket holding the radiator support to the left fender. I don't see three holes to mount the TI amplifier to the radiator support. Did all 66 radiator supports come predrilled for TI? I glanced at the AIM, but I must admit that I am not very good at interpreting mechanical drawings. Do you all think my car originally had TI? If so, how do I mount the amplifier properly? I have attached some pictures, including the wiring near the distributor.

[Ken A.]

Re: Transistor Ignition - was it originally on my car?

It was supposed to be attached to the inner skirt. Looks like the body shop replaced the skirt & rigged up their own mounting system is my guess.

[Loren L.]

Re: Transistor Ignition - was it originally on my car?

As a comment, AIM drawings are illustrations, NOT blueprints, so don't use them as such.

[Ken A.]

Re: Transistor Ignition - was it originally on my car?

Loren,
The OE skirt had 3 dimples to show the location of the holes.

[Mike E.]

Re: Transistor Ignition - was it originally on my car?

Loren,
The OE skirt had 3 dimples to show the location of the holes.

Ken,
Do you know if that is true of 68-71 as well? I've seen a great variation in TI locations for the 71 LT-1s I've had.

[Loren L.]

Re: Transistor Ignition - was it originally on my car?

In late '65s with TI & A/C, the three holes for the conventional regulator were predrilled in the skirt, but were NOT used with TI; the regulator was held up to the inner skirt and the three hexhead sheet metal screws were blown into the skirt with an air tool. I wonder if there is a determined date as to when the molds were changed to include the dimples.

[Bill W.]

Re: Transistor Ignition - was it originally on my car?

Joe the wiring and tape looks like my 65 . My 65 has three mounting holes on the front of the core support . I would say yes based on the wires and tape .

[Joe R.]

Re: Transistor Ignition - was it originally on my car?

Hi Ken,

I suspect you are right about the body shop. Everything that could be "creatively" mounted is. Sometimes Bubba is a professional!!! No wonder there isn't three holes in the radiator support to mount the amplifier! Can you tell me where on the inner skirt? Can you provide pictures?

Thanks for the info!!!
Joe

[Joe R.]

Re: Transistor Ignition - was it originally on my car?

In late '65s with TI & A/C, the three holes for the conventional regulator were predrilled in the skirt, but were NOT used with TI; the regulator was held up to the inner skirt and the three hexhead sheet metal screws were blown into the skirt with an air tool. I wonder if there is a determined date as to when the molds were changed to include the dimples.

Hi Loren,

Now you've got me questioning the mounting of the regulator, too. Can you provide more info / pictures of where / how it should be mounted?

Thanks!
Joe

[Joe R.]

Re: Transistor Ignition - was it originally on my car?

Hi Bill,

Thanks for the vote of confidence! I read through a few old threads relating to this topic a while back. Isn't the TI amplifier mounted on the right side of the car in 65 (moved to left side for 66 / 67)?

Joe

[Terry M.]

Re: Transistor Ignition - was it originally on my car?

Ken,
Do you know if that is true of 68-71 as well? I've seen a great variation in TI locations for the 71 LT-1s I've had.

In spite of the great variation we see, I believe there are dimples in the original skirt on 1968-72. It appears to me there was little to no use of those dimples in mounting the TI amplifier. What puzzles me is that drilling the three holes in the proper orientation would be significantly more difficult without using those dimples. My observation is the workers at St Louis took the path of least resistance to accomplish their tasks, so using a system that is more difficult surprises me. There is clearly something going on here that we do not understand. They must have had some template of some kind that was easier to use than the dimples.

[Kenneth B.]

Re: Transistor Ignition - was it originally on my car?

In spite of the great variation we see, I believe there are dimples in the original skirt on 1968-72. It appears to me there was little to no use of those dimples in mounting the TI amplifier. What puzzles me is that drilling the three holes in the proper orientation would be significantly more difficult without using those dimples. My observation is the workers at St Louis took the path of least resistance to accomplish their tasks, so using a system that is more difficult surprises me. There is clearly something going on here that we do not understand. They must have had some template of some kind that was easier to use than the dimples.

Is it possible the holes were drilled from the back side with a template that would cause a variation in location?

[Wayne M.]

Re: Transistor Ignition - was it originally on my car?

....... I read through a few old threads relating to this topic a while back. Isn't the TI amplifier mounted on the right side of the car in 65 (moved to left side for 66 / 67)?

Joe

Yes, for 1965, passenger side mount of K66 amplifier (on front side of the rad support) for L79 & L76 without air cond, and with L84.

With C60, driver side mount for L79 & L76 (again, on rad support) because no place on RH, what with all the air components. The L78 amp was mounted on front of RH rad support.

[Terry M.]

Re: Transistor Ignition - was it originally on my car?

Is it possible the holes were drilled from the back side with a template that would cause a variation in location?

Could be, but one would think there would still be a more consistant location. I have seen one car (a ZR1 no less) where the hood and amplifier contacted each other and many others where one had to use brail to find the amplifier.

[Loren L.]

Re: Transistor Ignition - was it originally on my car?

On '65 #23561 (L79, TI & C60), even though the AIM page calls out the amp as mounted on the radiator support, it was located on the forward side of the driver's side inner shirt - the location that I'm used to seeing used by 435 HP '67s.