89 to 91 1/2 eng differances

[83 crew cab]

ok getting all the parts ready to put the motor to geather I am going to use the 89 intake and fuel system and by a banks intercooler setup becouse the intake is melted on the 91. 5. is there a large differance in power betwen the 89 pistions (more compresion) and the 91. 5 pistions I can get buy with hot tanking the 91. 5 and rering and bearing it. The 89 needs a sleeve. new set of pistion for 89 in the 91. 5 block $280 or just stay with the 91. 5 pistions? going to use the 91. 5 head. the cam in the 91. 5 is bad (Rust on lobe) is there any after market cams?? what injectors do you thank would work the best ? If anybodys sees anything wrong with this let me know thanks George

 

[Matt S]

If you are doing a rebuild why not look into rebuilding it to the 370 specs? I believe they are even ceramic coated pistons but not certain.

 

[Gary - K7GLD]

I too am sorta intersted in the rebuild/upgrade potential in the pre-'91. 5 Cummins. Not all that many miles on mine, but past overheating tendencies seem to have made mine display a slight weakness on 1 cylinder, and I have a small oil seepage/leak at the headgasket at the right front of the head. I feel I will eventually need to pull the head to at least replace the headgasket, and may as well do a valve job at the same time. BUT, if it appears more serious attention is required in the short block area - broken rings or piston damage, I might consider a total rebuild with CONSIDERABLE increase in HP, and at least a 3000 rpm redline. There really don't seem to be many places - NONE that *I* personally know of, who are equipped to go completely thru these engines with an eye to serious performance increases while STILL maintaining long service life and reliability.



Am I better off just eventually getting a later model truck?

 

[83 crew cab]

Matt do you know what the specs. are for the 370 thanks George

 

[Matt S]

No, I don't. I saw a signature of a conversion into an F-350 with a rebuilt 5. 9 using 370 parts. On an off-line question he mentioned they were ceramic coated pistons which would increase your max EGT's. I know that Diesel Injection Service in Pittsburg does performance work with larger Cummins engines so they may be a good source for advice along with parts.