Okay, I’m asking a little bit of a technical/annoying question here for one reason… I’m breaking in a new motor on the 1995 pickup 22RE and want to be fairly close on mileage for the first oil change at ~400. Other than that, I couldn’t care less how many miles I traveled, as of now (266 miles on the trip logger thingy).

I have newer BFG KO2s 33x10.50 R15 tires (which are not actually 33” tall, I’d say closer to 33-32.5” maybe, but close enough for my application), stock 4.10 differentials, stock W56 transmission, and stock anything else that factors in here. Yes, there are websites that attempt to calculate this by plugging numbers in etc, but I thought the brilliant folks here on YT would have experience and bust this out no problem. I don’t see the odometer trip logger being too far off, but it’s something that crossed my mind driving tonight. Plus, it’s a fun little discussion, and…. my brain is completely mush from Xmas shopping. As always, thanks for any help and expertise. Excuse my laziness and lack of motivation.

PS- The motor is from Jim at 22RE Perfomance in Chico, CA. So far, the quality and detail are well worth the wait. It runs beautifully.

 

Assuming the stock tires were the 225 75 15s

Multiple the displayed mileage by 32.5 and then divide by 28.3

 

I'd not worry about break-in mileage that precisely! The engine isn't going to notice the difference between 300 and 500 miles. The only reason to care as precisely as you're suggesting is if you were doing a detailed science experiment and then going to tear down the engine to make measurements. Are you controlling the RPMs exactly during this 400 miles? The outdoor temperature? Your acceleration profile (and thus load)? All of these things (and more!) matter to the engine. Side note: For aircraft engines, we base engine service on revolution count.

 

Hello! Interesting information. I usually don't do that sort of thing. If I have problems with the engine or it needs an 4.3 Vortec Performance Build, there is a good resource for this https://nashvilleperformance.com/4-3...ormance-build/, sometimes I load my engine, but the upgrade allows me to cope with overloads