Connecting rod "offset"?
Yes, those rods don't have an offset because they are pin guided rods. You have to compare apples to apples. A non pin guided rod has offset.
These were non-floating...
I bought a couple sets to have on the shelf for future projects. When I bought my broken 383 I thought I might use them on that rebuild but finally figured I didn't want to spend the $$$ money needed to make the engine any "better" than it was... I'll save that cash for the Gen 3 if I build it.
Anyway my old friend Jim Watson (RIP) worked for Roush for nine years in the engine department. He was a crankshaft specialist and was a wealth of knowledge about these rods. Roush uses Lentz rods but he was very familiar with all the brands used in NASCAR.
He told me they haven't used floating rods for several years. The non-floaters are lighter and they don't have to worry about the bushing pounding out in 500 miles. They toss the rods after every race so these things are for sale all over the web and are strong and inexpensive. You just have to adapt the pistons and maybe the crank to what you are building.
If the crank you are using has a large radius you need to modify the bearings to accommodate that radius. You can see that radius on these rods. So the opposite side is where you adjust the side clearance... this isn't anything you guys don't already know.
I spoke with Randy from RaceTec pistons at PRI and he suggested using washers to control the position of the rods with his pistons rather than 'pin guiding'. Got to admit that's a new one on me but it sure is feasible. Maybe I'll just use a traditional pressed fit... don't know.
Back on subject...
I've been working on this stuff for over 50 years and, until now, have never heard the term "thrust" used for rods. Cranks yes... rods no. I'll stand by my opinion that one side is machined to a different measurement to correct the rod side clearance only. The thrust bearing on the mains controls the crank. Any offset is limited to the pistons.
I have seen, and I'm sure you have too, many terms that were once universal to our language now misused either intentionally or in error. That's why we have dictionaries. Rod 'thrust' is one of those terms... IMHO of course.
Automotive Mechanics: Piston designs
