Are there any significant differences between a rasts nest form a 79 and that of an 83? Also, how about the acv. Doesn't that 79 have a thermal reactor instead of catalytics?

 

yea they are way different.
not compatable.
im pretty sure the sa had catalytic system even with the thermal reactor.
if you have a haynes book there is pics of both. the 79 in the main section and the other years in back.

 

79 had a thermal reactor, but no cats. there was a pre-silencer. I know because i removed this from a friends 79 to put on a header.