Yes, the pump is indeed GTE. I had my old one to compare to and it is identical.
As for tolerances, OF COURSE you should tear everything down and check all your parts for fit. That goes without saying for Cheap ebay parts as well as expensive speed shop stuff. You dont want to leave anything to chance. I took the pistons from this company and gave them to my machine shop to bore to and check for clearance. They also fitted up my stock rods and clearenced my crank while they were at it. I paid a bit more for machine shop costs but I felt very good about these parts after hearing what my shop had to say.
I have only a few miles on it so far but I can say that so far everything is perfect.
As for tolerances, OF COURSE you should tear everything down and check all your parts for fit. That goes without saying for Cheap ebay parts as well as expensive speed shop stuff. You dont want to leave anything to chance. I took the pistons from this company and gave them to my machine shop to bore to and check for clearance. They also fitted up my stock rods and clearenced my crank while they were at it. I paid a bit more for machine shop costs but I felt very good about these parts after hearing what my shop had to say.
I have only a few miles on it so far but I can say that so far everything is perfect.