The main case looks like aluminum, with a magnesium tailhousing, so I assume is is a toploader only case? Both of my Jericos have magnesium cases, with upper and lower covers, but I think the aluminum cases were only available with just the top cover. I think the DR4-4 versions only came with the aluminum top cover case, which you would think should be stronger, having only one opening. If you are going to use factory mechanical clutch linkage, I imagine you will need to obtain a stock type, longer front bearing retainer to replace that cut down retainer, so you can use a conventional throw out bearing. Both of my Jericos have 3.19 low gears, and I really like that, gives more starting line ratio without needing to run so much rearend gearing, and possibly revving to much at the finish line, plus you can get a good launch without having to rev so high when dumping the clutch. It does make the drop between gears a bit steeper, but both my FEs and the 331 small block don`t seem to mind the drops that much. Should work really well for you, and likely at least 20 -30 pounds less than the Toploader. I am sure you will love it. Nice score. By the way, I still have my Jerico manual and parts guide, but since you have a 4-4, I doubt any part numbers cross over from my older paperwork. You should just contact Jerico and get the newer relevant information. You may also want to ask what trans fluid you should use. On mine, I use the Redline "Shockproof" gear oil, which is supposed to provide some cushioning between the teeth, and really clings to the pieces. Just don`t spill it on asphalt or concrete! A racing buddy used some regular gear oil in his new G Force G101A, and break some gears twice early on, once he switched to the shockproof oil, never had any more issues.