Hey Jeff, just to let you know in advance that any of the current NIMH you can buy on the market will be too big for the slots on the 10L. this is 100% confirmed as i have a 10L myself that i owned since they first came out back in the late 80s which i am trying to revitalize the car just for fun.
my suggestion would be to buy a 1S lipo on one side of the car and electronics on the other and balance the car with weight. or if you can go saddle just like the old days but with 2S lipo and just stick a 27T stock motor for power.
if you are going with lipo, make sure the bottom of it is flat without the humps.
post a pic when you are done.
good luck and have fun!