Don't knock V-6 700R4's in general. The 4.3liter trans has the V8 bellhousing and same exact drums and geartrain as the V8's but generally the V6's don't have the power to do damage to the trans. So you get a great piece that hasn't been beat up on. I recommend that trans specifically all the time.
Unfortunately if you really do have a 2.8, it will have a different bellhousing and inputshaft, rendering it useless for any V8 use.