I'd put that into the '59 and not think twice about it! Paint it Blue if it makes you feel better. Why wouldn't you want the 261 in your truck? About one in a few hundred people at the truck show will ever know that you don't have a 235 anyway. Impress yourself, not the judges.
I'd be willing to bet that, along with better power and torque, you'll also get better fuel mileage from the 261, because it won't be working as hard. Paint it Detroit Diesel Aspen Green or 261 yellow, and people will literally be drooling over your truck. Go on and treat yourself, you earned it!
Last edited by k10; 03/11/2011 12:43 AM.