1970 LT-1

[Charles S.]

I am restoring my 1970 LT-1's smog system. So far I have all correct components except for the diverter valve. My question concerns both engine performance and ncrs judging. A nos diverter valve with correct numbers and code has been quoted to me at about $600. I am sure that will work fine and receive full credit on judging. However, I am curious as to whether a new GM replacement diverter valve bearing GM part # 17084024 and sold for about $78 will be functionally correct and receive close to the same amount of points as the nos diverter valve. Any advice or information will be greatly appreciated!

[Joe L.]

Re: 1970 LT-1

Charles------

The GM #17084024 is a direct replacement for the GM #7029199 diverter valve originally used for your application. It will be 100% functional and it will fit perfectly. However, the configuration of this valve is VERY different from the original valve. For one thing, it is constructed of PVC black plastic material and has very little "metal showing". The original valve was constructed of zinc diecast material with some stamped steel components. It is of a different design, too, and has no muffler like the original valve. I would expect that it would lose 100% of the originality points assigned to the diverter valve, but I can't tell you that, for sure.

[Michael W.]

Re: 1970 LT-1

Usually GM service replacement parts do not warrant complete originality deductions. Having NO valve present or some bubba inspired transplant from a f_rd (for instance) would be considered a greater deviation from typical factory production than a correct GM service piece, and deserve a complete deduction. Typically the points removed for originality would be moderate to enable the owner to also qualify for condition points. If in this case the valve was new out of the box, there would most liekly be NO deduction for condition.

In a practical sense, it may be wise to evaluate the benefit of the NOS piece on a dollar-per-judging point basis. If the car is also driven to any great degree, thought should be given to the fact that diverter valves have a finite life.

[Patrick H.]

Re: 1970 LT-1

Mike,

I think the operateive word here is "usually."

For example, GM service distributor caps are black and have no wording on the top, appearing exactly the same as many other brands. In fact, they might BE exactly the same as another brand, but reboxed. In any event, I have seen only a minimum of points given to caps like this.

If the diverter valve has essentially zero configuration like original, I think he might be lucky to get any points but it will be highly judge dependent. He may be better off finding an old unit from any other Chevy/GM engine of the early 70s as long as it was metal and somewhat close. Gut it and install it, and save the new plastic one for driving.

Just my two cents.

Patrick

[Jean C.]

1970 LT-1

Admittedly not having a clue what the diverter valve does or how either of them are configured, is is possible to put the guts of the new type valve in the housing/cover of the old type?

If the above is physically possibe, would the act of making such a conversion be considered counterfeiting?

Best regards,
Charlie

[Joe L.]

Re: 1970 LT-1

Charlie------

For all practical purposes, what you suggest could not be done. I don't think that the internal parts of the plastic and metal valves are interchangeable and the valves are not really designed to be serviced, although a few folks out there have devised ways to do so with the metal valves.

[Dick W.]

Re: 1970 LT-1

I think that the valve would lose in the vicinity of 90% of originality points due to the difference in configration, material, etc The remaing 10% would allow you to get condition points. Just my opinion.

[Tracy C.]

Re: 1970 LT-1

Charlie,

I wouldn't consider your suggestion of putting new guts in an old shell as "counterfeiting".

I my opinion components recieving internal upgrades shouldn't get dinged unless the modification alters appearance or performance in a way that is obvious on the judging field.

I could be wrong though..

tc