Does anyone know if the 9.75 rear in a Lightning is physically the same as the 9-inch rear? Is it possible to swap them without major modification work? the 9-inch is plenty strong and has a lot more gear options available.

 

Any competant performance shop that does this sort of work (shortening axles, welding tubes, etc.) should be able to fix you up with a 9 inch rear end...I did this swap on my old S10 after I put a small block in it...worked great. Make sure to ask for 31-spline axles and center section; they were the larger (stronger) set that were put in the trucks. Stay away from stock re-splines too, as they often twist when you launch with slicks (I twisted 2 sets). Currie Enterprises sells some good stuff; check out their ad in the back of Hot Rod magazine.

Unless you plan on swapping gears a lot, the cost of having the thing made to suit the L would greatly exceed that of just getting another gear put in your 9.75 rear end.

 

Don't forget you have some ABS sensors in the 9.75" that may not work well with a 9". How about a late model 8.8" out of a 6cyl F150 and build it strong. Should be able to make it plent strong. Less weight, easy parts options, no ABS issues, etc. Easy bolt in after it has been strengthened. Better axles and a good diff.

 

Good point brought up is will I be changing frequently and not likely. It's obviously not just a bolt in for a 9 inch and you're right, the cost of a beefed up rear exceeds the cost of a ring and pinion for the 9.75. Just wonder why ford chose this rear? Is it that durable compared to the 8.8 or 9 inch? Is the 9 not used anymore in any newer vehicles? Ford doesn't have these on the shelf? Doesn't matter. What it has is a 9.75. Thanks for input.

 

Good point Silver Bolt - I forgot about that ABS sensor back there.

Ford doesn't use the 9-inch anymore (also known as a poor man's quick-change) but I'm not sure why. It definitely was a strong piece.

The 9.75 in the L should hold up well as long as you don't get into a wheel-hop situation (which would kill any rear end).

 

The 9.75 in our trucks is way stronger than a 9". The 9.75 is based off the Dana rear used in the 1 ton chassis pickups. Our rear end uses massive 34 spline axles. I don't see anyone braking one of these babys anytime soon, aside from something defective.

If memory serves me, the 9" was used until either 83 or 84, where it was replaced with the 8.8" rear, 28 spline in cars, and 31 spline in trucks (like the Gen 1 Lightning).

 

Where's my plugs? See your NLOC forum. Wondering. and thanks for your input, now gimme your plugs! J/K

 

The main reason I think does not use the 9 in is because it requires more HP to turn it when it is under high load.I think the weight was an issue up untill the new lightning because the 8.8 in lighter than the 9 plus the gears would interchange with the cars.
U can make the 9 to accept the abs ring if you want not to hard if you have a GOOD machinist that is willing to take the time to mod the stock ring.Stan