Finally got the 12v in the 03 yesterday and have been running it today. the problem is that we couldnt get the factory tach to work and it has 4k springs in it but what is the safest highway speed to run it at 5spd with 3:73's. had a 95 with 4:10 and it maxed at around 75 or so so i know i'm safe their but the speed limit out here is 80 and at that speed it sure is loud. so what is the top speed for these 12v with the 4k springs. so far i'm geting about 20 real mpg at 70 nice to get fuel mileage again

 

thats an awesome rig #1, #2 if you have valve springs done with the 4k gsk you can do over 100mph without getting anywhere near 4k rpm i'd say it would be around 2850 at 100. my truck with 3.54 gears does 77 at 2000 rpm and 115 at 3000 rpm. youre safe my friend. it may sound like its screamin but it has alot more to it.

 

Ditto that.

Nick

 

thanks wasnt sure so i figured i would ask

 

Thats an awesome swap, you gotta post up some pictures, Heres a link to a rpm/gear/speed calculator I found awhile back, it might help or at least give you an idea, just type in your numbers and it calculates what you got. http://www.cumminsdatabase.com/pdf_f...r_ratio_01.xls