Double ditto....
"I have the chance to obtain a pair of Dells that were blueprinted and improved by Art Thraen and would like to see if they are as great and trouble free as I read. "
Yes, they are. How often on here have you read about someone tearing down their Dells?? Eleven years, now, and I've never opened mine up. The only trouble we've ever had has been "chirping" on acceleration which is easily fixed with different manifold gaskets (or blocking a port as Bill Drayer did). Other than that, they just go, and go, and go...... (OK, so I had trouble with one of mine practically falling off of the manifold and running weird, but that was MY fault, not anything to do with the carb itself!!)
Oh! And they're pretty easy to work on, too. Webers are easy, too. They just need workin' on more often..... Another plus is that if you ever do get a clogged jet, they're all right up on top of the carb where you can see and get at them. Isn't that better???
My only caution would be not to get a pair that's too big for your engine. Jake could help spec that for ya, as it's important to match the flow rates of the carbs to the flow rate of your induction system and heads to make them all perform right together. Again, Jake is fastidious about this, and "a man after me own heart!"