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GTSIO 520/550 vs reg 520 cylinders for GPU Conversion (COST?)

Hey folks, I know this is a "running dry" topic, because I've read everything I could find in SA Forum back to 2010 that relates to GTSIO 520 conversion. These forums are loaded with experience (and BS, as expected...lol), so I found most of the answers I was looking for, but this one....
Looks like the GTSIO cyl, parts, and rocker assy are getting costly. What is the going (avg) price for 6 cylinders, rocker assy, vavle covers, ready for pistons? Has anyone bought any lately?
Now, what about GTSIO 550's? Newer style cyl, are they worth the $? Anyone running a set?

All responses are appreciated,


Well-known member
As you should know gtsio rockers are really hard to come by. You will probably not be able to find this all together and have to gather together one peace at a time. i use gtsio cyls on a few of my engines and i had to make most of the parts myself. There was someone making after market parts a wile back ,but I do not know how good they were.
Good luck .