Just to clarify, there are two 1949/51 Lincolns...both used the 337 cid "F7" flathead V8.

The "baby" Lincoln used the 1949/51 Mercury body shell with Lincoln only taillights, trim and bumper.

The Lincoln Cosmopolitans have their own unique body.

The front ends are similar, but the "Lincoln" front end is stubbier than the Cosmo's.

Why have two different Lincolns?

That's EZ, originally the 1949 Mercury was supposed to be the 1949 Ford!

The Deuce looked at the prototypes, deemed the original 1949 Ford too heavy, so a crash program was undertaken to create a new smaller 1949 Ford.

Dick Caleal, who worked for Raymond Loewy, did the design work on the '49 Ford behind Loewy's back, as Loewy was contracted with Studebaker.

Caleal baked the '49 Fords clay model in his wife's oven. The entire design and chassis was created for the 1949 Ford in a month.

The only change from Caleal's 1949 Ford design were the taillights, changed from vertical to horizontal.

1949 model lineup: All new smaller 1949 Ford, the original 1949 Ford became the 1949 Mercury. The 1949 Mercury became the 1949 "baby" Lincoln.

Then there's the flagship, the 1949 Lincoln Cosmopolitan.

Originally it was planned to use the 1948 Lincoln 292 cid flathead V12 in 1949 Lincolns, but the V12 engine (based on the smaller "V8 60") was underpowered, smoked and burned oil like a diesel, knocked like a bill collector...so at the last minute, the V12 idea was scrapped, and replaced by the F7 truck engine.

All 1949 Lincolns have 3 speed manual transmissions w/overdrive. In 1950/51 GM's Hydra-Matic was offered as an option on Lincoln's, standard equipment on Cosmo's.

Hydra-Matic was used on Lincoln's thru 1955.