Can you decode my protecto plate for my '70? Thanks - Mark
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194370S404269 R
VO212CTH CAO12017W 2
POBO5A [bowtie]

1 3


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I recognize the VIN and I know the R means Rochester carb.
I also kno the CTH is the L46 350hp engine. The rest is a mystery to me

 

VO212CTH V= flint
Feb 12 (engine build date)


POBO5A transmission P= muncie 0 = 1970 model year
B05 = feb 5
A = wide ratio, M-20


CAO12017W 2 (this 2 just means Feb, month car was built)

rear axle, CAO = 3.70 posi, with 350 hp engine,

12017W ignoring that leading "1" ?? feb 17, W = warren plant

 

Thanks for the deciphering PRNDL !

It's amazing to me that they built these things as quick as they did. It was delivered on Feb. 26, which is only 9 days after the tranny was assembled!

Do you happen to know if having the CAO 3.70 posi, meant that that was an option, maybe G81? Some books I have say the G81 meant posi (even though all 1970's came with a posi from what I've read), while other books say G81 was an "optional rear axle ratio"... Did a salesman enter G81 on the bill and specify which ratio the customer wanted?

Finally, do you know what was the stock gear ratio, if one wasn't specified by the customer order?

Mark

 

Mark,

Small block date codes for Corvettes, especially base engine cars, tended to be very close to production dates. Big block dates were usually spread out a little farther, but even they could be pretty close depending upon the engine option in question.

Many items on your Corvette had production codes even though these items were not technically options. Positraction (from 1970 onward) is one example of this... Standard production springs are another. Both carry "RPO" codes (and even show up on the build order copy... aka, "tank sticker"), but technically aren't options at all. As far as ordering, the salesman would simply consult the powerteams chart and chose from the available rear axle ratios for that engine.

Changing from the standard ratio for a given power team to an optional ratio (as is the case with your car) was still considered an RPO... Cost was around $12 and change if I remember correctly.

The standard rear axle ratio for an L-46 with the M-20 transmission was 3.36 to 1... If the optional (at no cost) M-21 transmission was specified, the standard rear axle ratio was 3.70 to 1.

The M-20/3.70 is actually a great setup for drag racing although few buyers were sharp enough to order it. Final drive ratios in the first three gears are actually lower than an M-21/4.11 equipped car. Most people opted for the M-21 and the lower gears though despite the fact that the M-21 was intended to be a road racing transmission.

Regards,

 

Stan - thanks for the info. As far as C3's go, I've only ever driven mine, so I don't have another C3 to compare it to. However, I did think that the first three gears went rather "quick" when shifting up to speed.

That Z06 looks awesome. Here's a rhetorical question: How do you like it? Man I've been watching that car on Speed Channel and reading about it. I bet's it's phenomenal! How fast have you had it? And do you still have your license?

Your '71 will look great next to it when you finish it, also.

Mark

 

Mark,

Not a problem, glad that I was able to help.

The car is absolutely incredible. I've been fortunate to have driven some pretty hot cars over the years and the 2006 Z06 is certainly among the best. It's very fast as you would expect, but also very composed in going about it. Certainly one of GM's best efforts. I'm hoping to get some track time once the weather breaks here in the northeast... See what it's capable of.

How fast have I had it? I better plead the fifth on that one...

Thanks, I hope that it turns out as well as the '70 LT-1 I finished not too long ago... I have a room full of NOS parts for the '71, now all I need to do is get motivated enough to start the project.

Regards,

Stan Falenski