I believe the 3.8 liter was the predecessor to the 4.3
GM had a number of these 90* V6s years ago....
They were all cut down 90* V8s, starting with Buick's 3.8 from the mid 60s which was used for a few years....then sold the tooling to AMC....who used it in Jeeps...then GM bought it back during the gas crisis (1973/1974) and it was used in Buicks, Oldsmobiles and Pontiacs...Chevrolet meanwhile carried on with the 4.2 liter straight 6 which was actually a better engine in some ways, being in perfect primary and secondary balance compared to the shaky V6s until they were given the split journal crankshaft and later the balance shaft.
Chevrolet got in the act with a 229 cu in V6, which became the 3.8. Now I don't know for sure but the 3.8 might have been a cut down 5.0 V8 just as the 4.3 was a cut down 5.7. The bore and stroke of the 3.8 and the 5.0 are nearly identical, like the 5.7 and 4.3 are.
The easy way to tell a Buick V6 from the Chevrolet V6 was that the distributor was in the front, just like a Buick V8 whereas the Chevrolets all had them in the rear.
