Cars, power, times and not least, everyday performance all depend almost entirely on the seven P's. perfect prior planning prevents piss poor performance. I have used 5's on a dead stock 26. Wasn't particularly blown away. Buuuuut, when I started building and improving, they really started to shine. Would I have 5's again? You bet. Would I build a different way? You bet. For today's fuel quality and cost of performance parts for 26's, you'd be mad to not build a tough 26 and run it on Jew brew AND still look like a stock engine bay that can peel your eyelids off when you give it the nuts, because let's face it, the police these days are getting smarter, and the bullshart fines are also getting worse.
I've personally built big power 8's and after looking at graphs and seat of the pants, for a stock as ya nannas undies look with big block torque, can't really go past a 2.8 with a well sorted set of 5's and Jew brew.