hey i just swapped my 98 spec itr motor and trans on my 00 civic hatch

i love everything about it except the 5th gear highway rpms

i love my 15s and i love my 195/45 t1rs but i swear at 4000 rpms in at 62mph
and at 4500 rpms i’m at 70mph..

shoukd i consider doing an os 5th gear?? is it bad to cruise at such high rpms for hours if driving far??

my exhaust isn’t loud..
what do u mean keep my foot out of it?

yes but that means I can’t go as fast correct ?

You're not going to damage anything if that's your concern. Just make sure your maintenance is up to date and your using a quality oil. I have driven to multiple autox's/HPDE's over the last couple of years, which all are about 2.5 hour one way trip on the interstate. We usually sustain 90-100 mph the entire 2.5 hour drive, which usually puts me in the 4500-5500 rpm range the entire trip. Run all day and make the 2.5 hour trip all the way home. No problems! I had the same concern in the beginning that you do now and stopped worrying about it. This is on my B16 with 150k + miles.

I also have a 98 spec B18C setup I'm planning to swap in and from what I've read those who switched the the LS 5th, weren't too happy. The shift from 4th to 5th becomes awkward apparently. I decided to go the opposite direction and swap in the shorter B16 4th and 5th.

I'm at 5400 rpm in 5th gear at 75 mph on the highway. (205/50/15's)

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I don't ever want to hear anyone complain about high revs...!

what transmission?

is it normal to burn a half quart driving in high rpms for 300 miles .. like almost 2 tanks of gas