If I could ever find a 40 that I can afford I would like to build it with all parts older then 1960,I am planning on a Y block to the original drivetrain and do plan on doing alot of highway driving. I figured the gears would be 4.10 or 3.73s or were there any from the factory or aftermarket around 3.25,I have a feeling I might have to go with a 9 inch to get gears in that ratio but thought I would check and see what is available.
3.45 was available, and I think there are 3.23-ish but don't know if they are a modern alternative or original equipment.
Not sure whether they were available new, but there are 3.25 gear sets available now for a banjo. 3.54 gears were available originally. Honestly, after rebuilding a banjo, go with the 9 inch if you’re already thinking about it. Still period correct for what you want to do, much stouter and probably cheaper to rebuild.
I just want to build one like they did years ago but reality will set in since alot of those old parts are not readily available if on a out of state trip and something breaks,if this build happens it would be driven to Florida from Ohio. If a axle would break in mid Georgia could one be found and same with brake parts.
I've owned quite a few banjo rear ends and chances are if you buy a car its gonna have a 3.78 gear in it. Like 99.9999% of that era axle ive ever seen was a 3.78. Theres a wide range of gears available for them now. Theyre easy to build and anyone thats put one together knows they arent any more expensive than anything else. Im building one with a 4.44 in it right now for 1/8 mile drag racing. Theres not much to them
Just how much engine can they take,the original was 85 HP but I am planning on probably a little over 200 Y block that will have more torque then the flathead.
I dunno how much hp they can take but mines gonna be behind a 304cu blown flathead so I'll let you know haha
I look at it like this. If I found a complete car id have no worries about dropping an ohv engine in with an adapter to the stock trans and running it. If I bought a 40 minus the drivetrain id put a late 50s early 60 Pontiac olds rear or a 9 inch or something.
The banjo can take some decent power, the trans is almost always more of an issue in the over power department. The issue you will have is the torque tube. to use the torque tube you need an early ford type trans to bolt it up. You can change it to an open drive using a open drive 40's truck parts or one of the conversion kits out there. The downside to that is now you have no way to locate the rear anymore. you can use the wishbones after modifying them into ladder bars, stock ones will not hold up, and then building a crossmember to locate the bars in the frame. Or you have to create and install an entire new rear suspension, ladder bars, four link, parallel leaf, to support and locate your now open banjo. at that point you might as well update the rear to an 8 inch or 9 inch rear. An 8 inch is plenty strong enough for what you are talking about. As for the banjo weak spots, the hubs and the keys are the weakest link, then the axle shafts them selves. Getting the hubs to register properly on the axle taper is the key. Clean the hubs up and have them grease free, same with the end of the axle where the taper is and remove the key. Then coat the axle taper in layout fluid. now take the cleaned up hub and spin it on the axle taper for 5 or 6 resolutions. This will show you where the hub is actually making contact on the tapered end of the axle, by removing the layout fluid on the taper where it make contact and leaving the blue layout fluid on the areas it did not make contact with. Next put a thin layer of valve lapping compound on the axle taper and spin the hub on it, this will fine tune the axle taper to the hub taper and make full contact with both. Continue the valve lapping compound until all the lay out fluid in removed from the axle taper. Then clean all the compound off and do do the layout fluid check again to verify. Use a good quality hub key from an early ford parts supplier not a woodruff key from the hardware store. and torque the hub key to 250 foot pounds. This is how i was taught to do it by life long hot rodder in my area that's now in his 80's. it works and make a tremendous difference. once this is done the hubs have to stay with that side, you have literally lapped in the hub with that specific axle.
I have been driving my 40 with a 331 caddy and stock trans, torque tube and banjo with 3.78's for over 10 years with no issues, while I don't drag race it I have been known to get on it sometimes and get 2nd gear rubber. The caddy doesn't seem to care about turning 2800 rpms at 70 mph.....
I'm not necessarily disagreeing with you, but my banjo rebuild was a nightmare and was almost halted when I couldn't find a machine shop to turn down the old bearing races on the bells to press on new races. (not to mention how many inner axle seals I ruined before getting 2 in correctly.) I finally found an old school machine shop that could do it, but they are now out of business. If I were doing these all the time I suppose it would get easier and I would know where to source things. But, if they guy is already leaning towards a 9 inch, they are a much superior axle setup. I have a banjo in my 39 right now, and it's working just fine and I don't plan to change it. But if I were building this car, and it wasn't a period correct deal, I wouldn't mess with a banjo again.
If you end up going with a banjo, print this post out for reference! I can attest to the pain of replacing the structural component of the torque tube. Even mild flatheads can break those wishbones without the torque tube AND something else to secure it like a torque arm, or a 4 link, etc. Also following the lapping instructions.
The Jalopy Journal
