Re: Loaded 70 SS rag 4 speed.
 

Couldn't you get a m22 behind a 402-375hp? I think you could in a 70 l78 camaro.

Re: Loaded 70 SS rag 4 speed.
 

Yes it was possible for the 1970 L-78 Camaro,(released much later on),but it wasn't meant to be for the 1970 L-78 Chevelle.
I believe that's because the 1970 L-78 Chevelle was only assembled for roughly the first 90 days of production before being swiftly cancelled,all while the M-22 was being re-tooled for the new 454 coming out in late November 69.
I believe if the M-22 was available during the 1970 L-78 Chevelles' brief time frame,they would've allowed it.

Re: Loaded 70 SS rag 4 speed.
 

Book says

4 speed (wide range) NA with 6 cylinders M20 219.20

4 speed (close ratio) ( available with z 25 396 engines only) M21 219.20

4 speed HD (Close ratio) available with z15 263.05

PJ