Code on axle:CRW 0109B1
1970 EL-CAMINO supposed to be LS-6. Build date on trim tag,01D. Talked to the guy who has the Original Engine,Front Pad stamped,T0117CRV,Below that is K158973 wich is the vin off my EL-Camino. My question is,is the rearend a 4:10 posi or open.
THANKS
MIKE

Mike,

I'm fairly certain when the 4.10 (or even the 3.73) ratio was specified, Positraction was a mandatory option. Colvin's book doesn't shed any light on this, but I think it's true. I believe only the standard 3.31 ratio came as non-posi.

Bill,
Thanks. I was almost certain that is was a Posi,as the second owner I talked too said it would make noise when going around a corner. Plus I did not think you would get an LS-6 M-22 combo and not get Positraction.
Thanks
Mike

I think all 4-series gears required Positraction and Posi was optional on 2- and 3-series. FWIW, the 3.73 ratio is not listed after 1969, 3.55 was the lowest ratio before the 4.10 for 70s. The original rear you mention with 'CRV' is a Posi 3.31; the 3.31 (open) was the standard rear on all big blocks in 70 according to my GM kit, Posi was optional but may have been required as you say for certain applications.

The code CRW is a 4.10 heavy duty non posi rear. Someone may have put a posi in it, best way to check is to jack it up and spin the tires around.

Dale,

Mike mentioned CRV as the engine code, not the axle. His axle is CRW, which decodes to a 4.10. And I agree, a 3.31 open was standard on all 70 big blocks.


Blue,

What source are you using for determining that the rear is a non-posi? If you're looking at Colvin's book "Chevrolet by the Numbers", It's my belief that it does not specify posi for the 4.10 listings only because posi was a mandatory option with that ratio. Most or all of the other ratios are coded as either posi or non-posi only because there was a choice. Does that make sense :confused:

I know this is slightly off the subject, but isn't the real question here: "Why is the the original block at someone else's house and not with your car?"! Is he holding it for ransom? Is it repairable?

Just curious.
Sam

Hey Mock,
No problem with the question. When I bought the El-Camino about two weeks ago the original motor was not in it. After talking to previous owners I finally contacted the guy who has the motor. He has had it since 1979 sitting in his Garage. All complete he wants $8000. I am just looking at other components too see if they match. That is why I posted the Rearend Code.
MIKE

he wants $8000 graemlins/clonk.gif graemlins/clonk.gif graemlins/clonk.gif