Hey I have a 99 si with a b18a1 out of a 95 LS Integra. I don't know if the transmission is the stock si or also from the Integra. There is a serial number on the transmission but I don't know what the numbers may mean if anything. The number is S80 - 2006538. I am at about 3700 rpm at 80 mph if that helps too. Thanks.

 

The b18a is actually from a 90-93 integra. B18b is 94 and up integra. I'm not sure on the tranny but the b16 has much shorter gears than the b18

 

Id say its a ls tranny. Ls, gsr, and type r trannys are all S80's. The gearing sounds to be of an ls. My type r tranny is at 4500 at 80 mph

 

Yeah, I thought the b18a was from the older integra but the transmission had junkyard writing on it that said 95 LS and I couldn't figure out why the guy who owned the car before me would have gotten a 95 LS tranny and 90-93 LS Engine. But he thought the engine was a b16 so who knows. The engine has the plate on it that says b18a1 so I'm pretty confident that the engine is such. I can't figure it out...unless the junkyard had the donor car mislabeled. Anyway...thanks for the help.