Skymarshal,
BTW, is that a job title?
First, welcome aboard! Good site, lots of younger set here. Some old farts like myself, as well.
The "Esprit" model was not introduced until the '70 (and 1/2) Firebird.
There were no V6s in Firebirds until the mid-'80s. Some early models had a straight 6. If yours was one, it was an OHC 230 CID (3.8 lr). These cars are rare, and getting quite popular for restoration. There's also a small "crowd" of racers, trying to put these cars into the 11s in streetable form. Developement of engine parts has stagnated, but respectable power can still be made. The 250 CID version was in the '68 and '69 models.
By '70, the OHC engine was gone. Any 6-cylinder cars from then through at least '78 were the Chevy 250.
Resist any and all comments about the need for a Chevy V8 to "make it run". If you're going to put a V8 in it, be sure it's the RIGHT V8. In this case, it would be the Pontiac. Developement of the old Injun has hardly "stagnated". In fact, there are more performance parts and accessories for the Pontiac than ever before, including the '60s when it was THE engine to beat. Current information regarding the ol' Injun can be found in Jim Hand's "How to Build Max-performance Pontiac V8s", published by SA Designs. If you're going to build one, buy ONLY the book until you've planned the entire build. That can save you sending parts back because they're "wrong". Avoid generic "kits", too, as they won't have the modern stuff.
Since you work at Advance, it''s only fair to warn you. Forget ALL of what your computer parts machine tells you. Get real, PAPER books and study the variations of GM offerings during that era. The data migration people, charged with transfering the info from catelogs to disk, are NOT "car people", and don't recognize human error, erroneous data or anomolies regarding availability. Your comment about the V6 should adequately illustrate that. It may be 3.8 lr., but it's not the Buick 231 V6, commonly refered to as "3.8".
Ames Performance
Performance Years
These two companies supply restoration parts for Pontiacs. Pontiacs ONLY, so you won't get Camaro parts simply because they "fit". First rate quality, and good service, too.
If you wish more specific data, feel free to e-mail me.
Jim