I have a performance book on sb fords and the author said that he believed the '75-'85 blocks were not built very strong and are more pron to cracking. Does anyone know anything about this "fact". It sort of concerns me because my block fits into that range and I am planning on building the motor up to a good hp increase.
The 68 through 75 blocks were made better but unless you are building a 500 or 600 horse monster you should be fine.
I can tell you this, my old '74 tall deck 302 block would not take the pressure of 18 PSI boost and a 1/2 second of detonation! As soon as I heard the abnormal noises, I let off the throttle...just to find out that it was already too late. Broke a dime-sized hole in the #6 and #7 cylinders. So far, the '93 block is holding up just fine, even at 24 PSI boost-- knock on wood
From what I've heard, a 1990 - 1993 and 94 Cobra 5.0's can withstand 600 h.p. repeatedly (with a stud girdle). 700 h.p. is real limit - and only limited to 10-12 runs at that. I've run my 347 to 600 horses over 50 times (yes, giggle gas was used) without any problems. All components are forged. The weak link now is the block. Now, a "Mexican" block is supposedly a better block - as it is said that there is more Nickle content in the material. The argument continues on this subject though. I certainly haven't performed any metalurgical analysis. Now, about that 5.0 "R" block - THAT's a different animal!
