4.2 power

[JKATTY]

I have an 88 4.2 with the carter 2b carb. Jeep runs great. Idles perfectly and runs very strong in lower gears. When I bought it the timing was too advanced and the engine would ping. I retarded the timing and did the TFI upgrade which allowed me to then advance the timing a little still avoiding engine ping.
I have never owned a 4.2 but had a 4.0HO in college. Both Jeeps had 33x12.50 tires and factory gears. The 4.0HO would run about 80-85mph but my 4.2 that I currently own will only do about 70mph and will not hold speed in fifth gear. Is this normal for a jeep with this setup and with the tire size I have or do I potentially have a problem somewhere. I hesitate to do anything because it runs so well. Any ideas or suggestions.

[lah2420]

You've gone from 180hp, I think, to about 112hp with the 88. The tires and the 3.07 gears are killing it somewhat too.

[RBLUE]

Sounds like a bad case of 3:07 gear's.Go to 3:73's or 4:10's and your 5 speed will be right.My 93 yj came with 4.0 HO 3:07's and i could not use gear 5 at all.I changed to 3:73's with 31's Now i can use the hole 5-speed's.I also added the Tera-low 4.3-1 to my T-case and Low range is Wow SUPER LOW..
Hope this will help you.Good luck an'keepon'jeepin