Correct Speedo Gear

[BMartinie]

I just put a set of 3.31 gears in my 81. What color and # of teeth gear should the new speedo gear have? It still has the stock thm-350 trans.

Spring is here!!
B

 

[Dave L.]

Corvette never had a 3.31/ M38 (turbo 350) combo. In 1978 they used a 3.55/M38 combo (drive gear #6261784 driven gear #3987922) that will get you close. You would have to change the drive gear on the main shaft.
The only other choice is to see how far the speedo is off with the gears you have now. Then you can adjust by adding or subtracting teeth from the driven gear(about 5mph per tooth). My guess is you'll have to go with the first option because the speedo will be to far off to make an adjustment with available driven gears.

 

[BMartinie]

Gears

Thanks, Dave.
I know GM didn't make that an option for the Vette. But I have to think there are guys (and Gals) out there, in the Forum, that are running the 3.31 and 350 trans combo. I was hoping to gain some knowledge from their mix and match speedo gearing.
B

 

[Dave L.]

Sorry B. I'll keep my thoughts to myself.

 

[BMartinie]

Thoughts = Wisdom
That's what the forum is all about!