Turbo 400 or 350?
 

Looking at a '72 3/4 ton and trying to figure out the trans....what is the code on the spid for a turbo 350 and a turbo 400?

Thanks,

Re: Turbo 400 or 350?
 

Easiest way to tell fir me is a 350 wil have a kick down cable and 400 should have an electronic button. Also the modulator valve will face the rear on a 350 and the right side of the truck on the 400.
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Re: Turbo 400 or 350?
 

here http://outintheshop.com/options.html

Re: Turbo 400 or 350?
 

The modulator faces left on my TH350

Re: Turbo 400 or 350?
 

option cobe for both transmissions is the same m49. The only true way is to get underneath and look. Th350 has roughly a square pan and the 400 has a very irregularly shaped pattern.

Re: Turbo 400 or 350?
 

The 400 pan is kinda shaped like Texas. :lol:

http://www.honestcharley.com/media/c...-rpc-r9121.jpg

Re: Turbo 400 or 350?
 

most trucks got the same option number for 350 or 400 tranny as mentioned above... M49. A small handfull of trucks got mismarked M38 for the TH350.
Some will tell you the M49 was a TH350, and the M49* was a 400, but I call BS on that one personally.
And for the nay sayers, TH350 was avalible on 10, 20 and 30 series trucks, not just the 10 series.

Re: Turbo 400 or 350?
 

So, what options triggered the type of auto tranny you got? Getting the BB did it - anything else?

Re: Turbo 400 or 350?
 

That is a good question and point on the m49 option. 3 of my trucks have the th400, but only my 71 bb truck has the little * beside the option code. The 68 only has m49 and the 70 only has m49. 70 was built in canada, 68 was built in baltimore and 71 was built in atlanta so dont think that makes a difference.

Re: Turbo 400 or 350?
 

Even if the SPID reads M49, the firewall markings will read m38 if it is th350

Re: Turbo 400 or 350?
 

The 68 & 68 trucks would not count in this discussion since the 400 was the only 3 speed.
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