I have read there were 4475 LS5 cars made in 1970 (dont't know if this included Canada cars or not). Also anyone know if there is a rough estimate as to how many of these 4475 cars were convertibles???

I think 4,475 was the production # for LS6 cars. 4,298 is the # of LS5 cars. I don't think the # of ragtops is known.

According to Dan Carr's 68-72 poster information, it's a guess...albeit an educated guess based on the total number of LS5/LS6 cars and the ratio of convertibles to hardtops and the El Camino. Total numbers vary depending on the sources...so:

Dan has 4574 LS5s
3964 in the Sport Coupe
91 in convertibles
519 in El Caminos

Again, using whatever total numbers you like, you simply take the ratio of total LS5s to total V8s and apply that to the total number of Sport Coupes/Convertibles/El Caminos built and come up with a good "guesstimate" of models with LS5s or any other engine.

I'd highly recommend you get his poster if you're into production numbers. At $28 plus shipping, it's a bargain.

http://www.designscomputed.com/auto_pub/a_body_68_72.html