If fuel mileage is a factor, why not stick with the LN3? The LN3 and L27, especially when paired with the 2.84 FDR are highway cruisers, which, when modified and tuned slightly, can get crazy fuel mileage, and the fuel mileage is not easily affected by speed.

Admittedly, the above mentioned FDR paired with the LN3 or L27 does require some encouragement to get moving, but that is what the mods are for! The LN3 does love the 2.93 FDR.

BTW, you can plug the VIN into compnine and get the FDR from that, or check the RPO sticker on the spare tire cover.

Thanks for the reply , but i decided not to do the SC swap. I am however going to do the L27 top swap. I do have my final dr ratio'* for both cars. 2.84 for the Olds and 3.06 for the 92 Regal and both get the same milage.
I want to do the gear or trans swap now because i'm going to drop the cradle soon. New eng cradle mounts, F-41 steering rack, 32mm bushings, tie rods ball joints, poly end links etc. All moog parts. It will be easier while its on the floor.
Now if i can only find out if the W body trans mts will work in the H body. When i ran the vin it says the 92 is a 4T60 and not 4T60-E.
Can the E trans be made to run on vac system ? Can 92 ecm be swapped esaliy into 90 body to run L27 ? If you can get a supercharged to work why not the L27'*.