GMAN, that $750 Mark is a little bit of a fluke but the mere fact its $750 tells me there is PLENTY wrong with it. Also any Mark no matter how well loved (with the rare exception) will have several or more dor dings/rock dings in it. And $600 for a rebuild? Hmm, interesting. A frshen up of bearings is not a rebuild. Pistons are a wear item too as are the valve guides and valve lash adjusters. To PROPERLY rebuild a motor you would replace all those parts as well.
Even if only replacing rings, seals and bearings is $600 then I would also be weary. A good pair of head gaskets is $100 (not talking chit $30 ones), valve cover/oil pan/front/rear mains, piston rings and bearings, new head bolts alone will push you near $600. Then to have the heads and deck lapped (a 100k+ motor will need that) and to hone the mains as well as rods by itself will also eat up most if not all that $600.
Now thats the proper way to rebuild a motor. Anything less is making a motor that will not last and/or make the power it should. I have seen more then one modular and quite a few old pushrod 5.0s blow up in no time from an improper rebuild. After asking their respective owners if the previous items were done its usually a "no" in the answer recieved.
Even if only replacing rings, seals and bearings is $600 then I would also be weary. A good pair of head gaskets is $100 (not talking chit $30 ones), valve cover/oil pan/front/rear mains, piston rings and bearings, new head bolts alone will push you near $600. Then to have the heads and deck lapped (a 100k+ motor will need that) and to hone the mains as well as rods by itself will also eat up most if not all that $600.
Now thats the proper way to rebuild a motor. Anything less is making a motor that will not last and/or make the power it should. I have seen more then one modular and quite a few old pushrod 5.0s blow up in no time from an improper rebuild. After asking their respective owners if the previous items were done its usually a "no" in the answer recieved.