C2 J65 and Power Brakes! Duke?

[Alan Drake]

I think that Duke discussed this before, but can not find posting so,

It has been noted that more 64 cars seem to exist with Power Brakes than made, much like BB. However one reason may be that when the J65 option was ordered the Power Brakes came with it.

Now look at the Summer 2007 Restorer (V 34, No 1) on page 21. It shows the J65 option and J50 Power Brakes as unique options. Now I understand that GM made one order certain options as a package, so if you ordered the J65 GM may have required you to order the J50 with it, however would GM count that as one of the cars made with J50?

So back to original question, is the J50 option really on only 2270 cars??

[Duke W.]

Re: C2 J65 and Power Brakes! Duke?

For a long time I was under the impression that J-50 was not available with J-65, but a few years ago I changed my mind and now believe that J-50 was available with J-65, but there were probably very few built.

Given the extreme sensitivity of J-65 to temperature, I consider J-65 and J-50 to be a VERY bad combinstion, especially if the car is used for extreme driving like race track hot lapping. When very hot J-65s essentially ACT like power brakes. Contrary to fading like conventional organic linings, the metallics do just the opposite - the friction coefficent increases rather than decreases with temperature. And if you combine this temperature sensitivity with a vacuum booster you may end up with the system than is difficult to modulate at a point in time when you REALLY need good modulation and feel.

So if we believe that J-50 and J-65 could be ordered together, the 2270 J-50s in 1964 include both J-50 with base brakes and J-50 with J-65.

Again, I would doubt if very many J-50/J-65 combinations were built. I ordered my SWC with J-65, and didn't even remotely consider J-50, so I made no inquiry as to J-50's availability with J-65. In that era if you ordered a Corvette with performance options like a SHP/FI engine, 4-speed, Positration, and J-65, you generally escewed "comfort and convenience" options, but this began to change in the mid-sixties, which is why L-79 used the "small" oil pan - so P/S could be installed as an option. And L-79 was a popular option because it made nearly as much power as mechanical lifter engines, but eliminated the "hassle" of adjusting mechanical lifters, which in my opinion is bunk.

They're easy to adjust - and if adjusted properly don't need to be done that often - and in addition to making more power, mechanical lifter cams extend the useable rev range, so average power through the gears is greater, which is a perspective that is usually overlooked.

Duke

[Alan Drake]

Re: C2 J65 and Power Brakes!

Well as we have discussed before my car has J65 and J50 - just talked to original owner who I found Sunday at Nationals. The car in the Restorer has the two options and an April 64 next to me in the show has an original window sticker with the J65 and J50 options. (took picture) Now if these options could only be ordered separately then the number of around 2270 would still be valid, thus making the J50 a low option.
Well not sure what this all means, but
Thanks Alan

[Alan Drake]

Re: C2 J65 and Power Brakes! ERROR

Sorry, the picture I just took of the April 64 with J65 and power brakes does not list J50 as an option, but it has it! (saw power and just read brakes it was window) Sooo, looks like we may be back to the J50 being part of the J65 option, but what about the restorer!

[Duke W.]

Re: C2 J65 and Power Brakes! ERROR

It's not clear to me what you are saying, but J-50 was NOT PART of J-65, nor was a power booster included with J-65 (A power booster WAS included with Z06 in '63, and J-56 in '64, but that's a totally unrelated issue to J-65.) I ordered J-65 on my special order SWC, and it does not have a power booster.

It's easy to add a power booster to a Corvette, so the existance of a power booster with J-65 brakes proves nothing without documentation.

I am still willing to believe that J-50 and J-65 could be ordered together on the same car, but the evidence is not conclusive IMO until someone can produce a bonafide original order copy or window sticker or other conclusive documentation with both options listed.

Duke

[Philip C.]

If it helps

I had a very orig 63 with J65 and no power, low mile car with the orig shoes, drums, wheel cylinders etc, it had a 340 motor. Phil 8063

[John G.]

Re: If it helps

My '64 still has the J-65 brake linings it came with from the factory. 300 hp, no power boost.

[Alan Drake]

Re: So where did all those J50 come from

Well from a closer look at the window sticker (think its original) and feed back it would seem that the J65 did not come rolled up with a J50 power unit.
It sure seems that I've seen at least half of the 22xx made. Guess my first wise guy statement my be true, ie the J50 is like a BB.
Thanks All
Alan