My experience in front of members on this site.
red 70 Duster 340 4spd all original with AC and manifolds. Carter 750 391's old L60 x15's
Side by side up hill, Dead stop and Rolling kick
white 71 Duster 360 380 horse crate motor 4spd with headers Edelbrock 750 391's with 275x60 radials
The 340 would pull on the 360 so hard on the bottom the 360 could not make up the ground on the 340 on the top
We tried switching drivers . Timing, with and without air cleaners . The 360 could stay with the 340 on the level or down hill only. Neither would hold ground to the multi color 68 340 4 spd GTS
We had other cars we would toy with but theses were all 4 spd's with 391's
The brown 72 Duster 360 magnum crate auto 355's went 13.40's in a quarter. It was a fun street car but no comparison to a 10.5-1 comp. 340. The early 340's pulled like BB's in the little cars
View attachment 1715905959
View attachment 1715905961
View attachment 1715905962
