70 SS chevelle = my most admired car EVAR.
no, There were 2 transmission options with the LS6 454 (450hp) the TH400 or M22. The LS5 came the same way, But there were a rare number of M-21 LS5 cars made in 70.
Production numbers for 1970 SS by engine (tried to find the production of th400 vs. m-22 but failed)
L34- 396-350 hp-51,437
L78- 396-375 hp- 2,144
L89- 396-375 hp- 18
Alum. head
LS5- 454-360 hp- 4,298
LS6- 454-450 hp- 4,475
http://www.chevelles.com/shop/ss_ident.html