HELLO TO ALL FR NOVA SCOTIA MY NAME IS RICK IVE BEIN WORKING ON MY 89 1500 FOR A YEAR NOW 6/305/NOW A 350 RUNNING A 305 COMPUTER IN IT/TURBO400WITH A SHIFT KIT HAVE REPLACING EVERTHNG EXCEPT THE BOX(THIS WINTER) IVE BEIN INSTALLING GAUGES FOR EVERTHING/2 TRANS TEMPS 1 IN 1 OUT/2 WATER/VAC/VOLTS /AIR IDLE/OIL TEMP/DVD PLAYER/I PUT A BIG COOLER FOR TRANS A SOLID FAN AND COLD AIR INDUCTION PROBLEY HAD EVERY PROB GOING THAT COULD HAPPIN .I NED ADVISE ON GEARS FOR THE REAR END I THINK THERE 323S////80MPH/2900RPM /EVERYWHERE I GO I LEAVE RUBBER MIGHT BE CHANGING THEM .
ANYWAY HOPE TO BE HELPED AND HELP OTHERS
THANKS RICK

 

Hello! I had an '89 1500 as well and I believe it originally had a 3.43 and I replaced it with a 3.73. My top end went out the window...
Do you want top end? If you had 3.23's, that would be top end...Higher the ratio, the lower the gear.

http://www.chevyhiperformance.com/te...o_calculating/