70 carb, choke rod & stove & vacuum advance line

[Juliet P.]

Re: 70 carb, choke rod & stove & vacuum advance li

Roberto to the rescue again with the pictures! :-) Thanks a zillion! I do have one of those with the Littlehouse writing on it. Whew! The relay I was looking at earlier must have been something else, but your photo straightened that one out perfectly. Mine looks just like yours, except somewhat grungier & dirtier looking. This internet is just amazing! Who would have imagined that someone on darn near the opposite side of the planet could help so efficiently? This NCRS board is just fabulous.

Thanks! ~Juliet... who sees some junkyard shopping in her future... somehow I don't think my secretary who enjoys shopping at Tiffany's will be accompanying me however....


Juliet's 1970 Corvette

[dennis]

Joe

Joe Interesting comment. If I disconnect the TCS on my 70 L-46, do I set my timing to 4 btdc as in 69, instead of 8 btdc as in 70?

Will my carb (7040207) perform/adjust to the 69 setting? If so,does that mean I could buy a 69 version L-46 (still available new) as a donner carb and sandwich my bowl section between the new air horn and throttle plate? Thereby keeping the numbers intact and replacing the leak prone parts? look forward to your opinion. Dennis

[Juliet P.]

Correction... Littlefuse NOT Littlehouse

Whoops... typo in above. I meant to write Littlefuse. Toon Disney made me do it! ~Juliet


Juliet's 1970 Corvette

[Jim T.]

Re: As Roberto said....

Juliet I think I still have the TCS solenoid that we removed from my sons 1970 Camaro many years ago when we changed intakes etc. I think I know where it is in the attic. I will attempt to locate it later this morning and compare it with my known original.

[Jim T.]

Re: Jim Trekell

Dennis I ran 10 degrees BTDC with the full time vacuum going to the vacuum advance unit when leaded premium was still being sold. Looking through my service record book, I went 8 degrees in much later years.

[Joe L.]

Addendum To Above Post

I determined last evening that the TCS transmission-mounted switch for THM 400-equipped cars is still available, but under a new part number. Originally supplied under GM #6462286, this part later became known as GM #25036207, then GM #8634475, and, currently, GM #8683502. It GM lists for $18.00. I expect that the configuration of the part has changed at least somewhat, but, it's still available for those of you looking for a functional replacement.

[Joe L.]

Re: Joe

dennis-----

As far as initial timing goes, it's pretty much an "undefined quantity" if you use your existing 1970 distributor configuration. That's because, using the centrifugal and vacuum advance characteristics of this distributor will not relate to the same characteristics of the 69 distributor. However, it's probably a moot point since you should try various initial advance settings and settle on the one which provides the best overall performance. Even the 69 setting in a 69 might be subject to improvement based on an empirical determination process.

As far as the carb goes, I wouldn't, for several reasons, recommend attempting what you suggest. First off, the 1969 300hp and 350hp carburetor which is still available under GM #7046904, carries a GM list price of just about $1,000. Although it can usually be purchased for a bit less, I really can't see cobbling one up for parts, especially since the float bowl, which would become "surplus" in your scenario, is the part which is the most deterioration-prone, causes the most trouble, and is the source of virtually all of the "leak problems" associated with Rochester Q-Jets. Third, there are differences between 69 and 70 carburetor major components(air horn, float bowl, and throttle body) and I'm not even sure if you can use a 1969 air horn and throttle body with a 1970 float bowl. 1970 carburetors are different because of the change to the CCS emissions control system from the previous A.I.R.-based system.

But, if you decide to go ahead with this, let me know. I'd like to get the resultant "surplus" 69 float bowl assembly from you.