I've been looking around for a convertable camaro of any year third gen to use as a platform for a build up and every one I see is 305ci & automatic. I am aware that there were some 5spd cars but were there any 6-cyl cars? If I do get one I will be scraping the engine and trans so I want to find the cheapest one I can find as long as the main parts of the body are in good shape.

 

The base convertible was only available with the 305 until 1991, when midyear GM offered the 3.1L V6 as an option.

I wouldn't suggest a 3.1L Convertible if you want to install a V8. At the very least you'll need an engine, transmission, transmission crossmember, motor mounts, passengers side brake line, front springs, fuel pump, V8 accessories, exhaust, etc. Its not very economical.