>i was wondering about older model chevy V6's.

Just to add a bit to what others said, The Chevy 90º V6 shouldn't be confused with the Buick version which is easily identified by the front mounted distributor. The Chevy was introduced in 1978 as a 200 cubic inch version and was based on the 267 with two cylinders removed. Later, the displacement was changed to 229 by using the bore/ stroke of the 305. Those engines were semi-even fire, utilizing 18º split crank throws. In 1985, the 4.3L version was introduced and used the same bore/stroke as the 5.7L V8. The biggest change other than dispacement was the change to full even fire with 30º split crank throws. This change required an increase in rod journal diameter thus the rods are not interchangeable with the V8 version. In 1986, the engine received the one piece main seal and roller lifters. In the early 90's, a balance shaft was added. Those engines can be identified by the taller timing cover. The next big change came in 1996 with the Vortec heads. Note that the Vortec label had been used before then, but the "true" Vortec heads are from 1996 on and have an 8 bolt intake, thus earlier intakes don't interchange. Edelbrock makes an intake for use with carb and Vortec heads on earlier blocks.

Bob