damn man if you did that with no slicks and a stock stall in a radix 5.3 with only a 3.25, I think thats damn good! The 80' is a pig and the stock stall in it is horrible.
I was only hoping for 12.7-12.8 with my Tahoe with STS GT67 on 6.0 with turbo cam, and PI 3200 in the 80' with meth and FMIC. Looks like I'll have to aim higher!
With a good converter and tires you'll have 12's all day long in an EC with a 5.3 and same size pulley on you radix. Very impressive IMO