Does a late 1970 vert suppossed to have a tsc solenoid (july 15th build) ? Not realy sure what it does....or if it is important but, I definately dont have one! base 350 motor thm400.......... Thanks

Not sure if the '70 cars had it, either, but I can explain what it do.
The TCS(Transmission Controlled Spark) is designed to restrict/eliminate the vacuum advance on the distributor until the car is in high gear. It is an emissions thing. Early systems had a delay timer mounted on the firewall that would give a 20-30 second delay before the solenoid would close, and allow vac. to the advance mechanism, but the later cars(late'74>) did not have the timer. Also, the earlier systems worked in 3rd and 4th gear(manual trans), but the later systems only worked in 4th gear. Automatics(if TCS equipped) worked in 3rd gear only.
On a manual trans, you can actually tell if the system is working by starting the car and getting it to operating temp. With the car in neutral, you can move the shifter to 3rd gear(clutch in), and after a short delay from the timer, the engine rpms will start to rise. Later car require you to use 4th gear, but the effects are the same...the rpms will rise about 800-1000 rpm from idle speed.
I'mma tinking the systems were used on the '70 cars, but I really don't know for sure, off the top of my punkin head. Someone else may know. If not, I can find out.

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Joel Adams
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My 72 LS5 with the 454 and T400 came from the factory with one. It did'nt have it when I got the car. I have not put it back on. From what I have learned I don't need it and the components are pretty expensive if you can find them.

I know that my 70 LT1 has one, and I am 99% sure that all 70s did.  And when you test yours, be sure to warm up the engine like Joel said, as there is a temp switch in the right side head to keep it from working with the engine cold.

Larry

The temp sensor works for cold, and overheat situations. If the engine temp gets too hot, it will kill the power to the solenoid, effectively retarding the timing. I thought aboot the temp sensor after I posted my earlier response, but I had to hit the road...no time to correct meself.
I'm thinking the system was brought into play for the '70 model year, but I just doesn't remember without looking at some specs...
memory....it's a kewl thing to have...

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Joel Adams
C3VR Lifetime Member #56    
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(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thanks Guys.....!!!! I guess I am not gonna chase this one too much...sounds like I can leave it alone and never realy know the diffrence. I can put the $$ into more needed things,  LIKE  finish my needed peices of ignition shielding!   

Should ya change ur mind, here is one for ya

My 72 had it, I removed it when I put the HEI ignition in, one of the tabs was broke anyways.