The 603.97 is a bored and stroked 603.96. The 603.97 is labeled a rod bender yet its 92.4mm stroke is exactly the stroke in the 617. The 603.97 bore is 89mm which is 2mm smaller than the 617. Anyone know if the 603 and 617 have the same deck height?

Sixto
93 300SD

i dunno but i would bet the deck on the 603 is lower. everything was done to make the motor more compact.

i dont think the stroke on the 3.5 has anything to do with the rod bending proclivity.

my favorite theory is that the head gasket leaks fluid into the combustion chamber while the engine is stopped and then the piston comes up and is hydrolocked or partially hydrolocked. it takes i think only about 1.5 teaspoon of liquid to fill the combustion chamber. more than that will bend the rod.

it only takes a little. when the rod is bent, the rod twists and then the rocking motion of the piston is causing a binding situation in the cylinder and accelerated wear. they will get so bad that the cylinder will eventually have virtually no compression.

so if you are looking at 3.5s and they are missing at idle....walk away. i looked at a couple like this and passed even though i didnt know about the rod bending reputation. i just didnt want one with a cylinder down unless i could buy it cheaply enough to have the head off and go through it.

good luck

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.