We have proven this numerous times that 53 to 58mm is a difference not mainly in HP but more TQ and the rate of the climb to redline. Heads done properly with Stage II cams and tuner will walk all over a stock setup. Is it worth it that is up to you.
A destroyer crank in a 1130 makes it a 1177 and in a 1250 it will be a 1302. You will need to do a little clearance in the bottom case half where the rods come around. A 1302 with heads and cams will scoot no doubt. I have one with over 7k miles on it and I beat the tar out of it.
D.A. FITZGERALD CO., INC. / FITZGERALD MOTORSPORTS Your one stop performance VRod shop!
Authorized dealer for Vance & Hines, MegaCycle Cams, CP Pistons, Brown's Plating, Carrilo Rods, ARP Studs, Falicon Crankshafts and Diamond Heads.
Services offered: Case Boring-26T Pulley-58mm Throttle Body-Slotting Sprockets-Pinning of Bearings-Custom Machined Wheels & Rear Pulleys- Engine Brace Kit