That's what I've been using for the last 5 years as my second battery. It's held up well and only just recently seems to be weakening a bit (in the sense that it doesn't seem to hold a charge as long when I'm parked for several days). Mine needed a booster to make it tall enough to use the stock trays - I think it's a piece of 3/4" plywood.
1976 FJ40 - green and mostly stock
1996 FZJ80 - not so stock