Technical Early Slingshot-How to short the rearend axle?

Hi guys!

Im going to build a early slingshot dragster, I've collected som parts n stuff, BUT, How to short a 39 ford rearend? the tubes are coned and how to short the driveshafts?


Thanks

 

i THINK, but im not sure, that you can cut the end of the axle off behind the backing plate flange(after putting it in some kind of jig to keep it aligned) then cut the tube down to size. then pie cut the tube where the old seam was, squeeze it back together and re weld it. move the end back into place and weld it back on. as for the inner shaft, i believe you would need to machine that down on a lathe and then cut a new keyway and threads on the end.

but just FYI a lot of the early ones didnt shorten them, at least from the pictures ive seen.

 

mine I cut the tubes where it measures 3" on the inside inserted a sleeve and used big ford bearing and 31 spline axles there are kits to use 28 spline axles. in your case I think is to cut the housing a couple inches shorter then cut the bearing ends a couple inches machine a flange that fits the out side of the smaller tube and the inside of the bigger one and add gussets if needed and machine the axles to fit.Do you have any pics of the style of dragster your building,what are you using for a motor>

 

Sounds like a good solution too shorten the tubes. Im going to take the axle appart and start to look at it =)

Yeah, I've seen those to with unshorted axle, but, I prefer shorted most =)

 

Im going to take some pictures of my collected stuff, and Im also attach my insperation pics =)

How can i attach pics? I can put them on my "page" here..

 

check out this build he did a really nice job
http://www.jalopyjournal.com/forum/showthread.php?t=595703

 

You realize they can't handle any significant power don't you? If you have a couple hundred hp and it hooks up at launch there is a very good chance you'll tear up the rear.

 

oj in my build I'm only using a 70's style 301" sbc and a powerglide should be running by spring if there isn't any more set backs.

 

Hm...maybe Im going to cheet just a bit, Strange axles custom make for these type of axles, should "easy" handle my motor... But it maight cost a little bit =).. Yeah, I dont wanna loose my family juwels beacuse of a rearend BAM! =)

 

Uh...look at 1960's fuelers, when they were running around 180 in the quarter. What kinds of rears do you see??
I believer the Chrisman dragster made it into at least the low 9's with MODEL A based quickchange and Ford tapered axles...

 

I kinda don't think so Bruce - if he did he would never have invented the 'Christman' rear - one of the very best rears in the industry. The minute they got a tire on them they'd rip the rear right out.

 

Don't have the old books here, but look at this crummy new magazine:
http://www.streetrodderweb.com/milestones/0007sr_jack_art_chrisman_dragster/index.html

Them's is a Ford rear, and I believe there are pics in the older magazines I have of it with hubcaps off...showing Ford axles. From the time period alone I believe it is A based, not V8. First drag car to 140, breaking the 1G "barrier" Many early '60's slingshot fuelers into the 180 period were running V8 quick changes, some with special axles, some with Ford axles as supplied bt ch***is research...shortened Fords with lots of attention to taper accuracy, polished and shot peened.
Ch***is Research supplied early Ford components for dragster rears well into the '60s.
One of the flatheads run in the Chrisman car was well over 400 HP, and the '60's dragsters were running hemis in many cases.

 

But that banjo was not against his teabags,& the metal gears were not over 50 years old at the time.I hope you baby mak'in days are over before you get that dragster finished.Put a big olds in there & save the boys.

 

Chrisman ran an early Ford rear in his hemi powered A sedan.
Ohio George Montgomery ran an early Ford rear in his BLOWN Caddy powered, record holding 33 Willys coupe (before switching to blown 427 soch ford).
Do some research, they can be built to handle more power than you think.
That said, unless you are looking for a specific style/look (which is why we build these things the old way) a different rear may take the power with less modifications.

 

About forty years ago, we used later (early fifties?) Mercury axle ends and brakes on the dragster. We tore up a bunch of transmissions, but never hurt the rear end.

 

Go with the 9" axles and brakes on the banjo rear end and use new R&P and there will not be a problem(if you use a truck rear end axles you can keep the 5.5 bolt pattern). Flatomatic makes a coupler for the Banjo rear end. If your going with a Flathead Fatomatic also makes a shorty tail set up that makes the C-4 shorter than the powerglide shorty.

 

send it to Cooks machine shop in Los Angeles. They have been narrowing rears for 60 yrs.

 

going for 9" ford MW spole =)

Thanks for inputs!!

 

HaHaHa, don't screw with Bruce or he'll dig out some facts and put the smack down on ya.

 

I have immense respect for Bruce, but i know drag racing and i have looked inside of a few banjos' and they are spindly as chicken bones - axles, gears and parts/pieces.
You use one of them behind moderate power and have a tire that hooks up and you will tear one of those things to shreds...why modern pinion gear shank is larger than those axles. And i use those axles to make things from in the lathe and i know exactly how 'hard' they are so don't try to tell me about some special metal they are made from. If they were so good in blown world record bad***ed g***ers and fuel dragsters why did they become obsolete? I love the banjo, but i know its' limitations.

 

whoa, it's called a joke. chill out man.

 

Good choice maybe not periode perfect but helluve much safer
You might consider a mopar 8 3/4, as they are smaller, and will take the HP, and they are pp

Good luck, see you at Kjula!?

..............................
Taildragger&fenderless

 

I am gonna shoot some pics on the rearend and also some of the rest of the fed build =)

 

Ford 9" has been around since '57.

 

Can I agree with Bruce AND Oj both? Sure, the banjo WAS used when there wasn't much support for any of the bigger axles...but now there IS. And if my nuts were d****d over it, I'd want the strongest piece available...

 

The fact remains, if you pick up any late fifties or early sixties magazine and look at what was being used in the short cars of the era, most still used a narrowed early Ford unit. The first one off the top of my head I can think of that everybody knows and is easily checkable is Dean Moon's dragster. V8 quickchange and shortened torque tube with an in-and-out box. I did notice that by about '62 or so, lots seemed to be updated with Merc axles, Dean's included. By about '64 when fuel came back, the rear of choice shifted to fifties Olds stuff.

 

I got both sides, the banjo can be used and shortened, I cut mine off behind the backing plates, and messily welded the tips back on with an axle inside to make sure alignment held, it worked...then, cut a hole in the banjo side on the flat side of the ring gear, and welded in a nut into the hole, then put in a bolt to hold pressure on the ring gear to keep it from flexing too much, ran over 70 runs with a nitro Ardun and never broke it, Chrisman, Cyr, and lots of other blown Chrysler guys did run banjos (especially in Ch***is Research TE-440 and K-88 cars), which Scotty sold with narrowed banjos.... but if you are going to try it, run a "nut cover" bolted to the sides!!!, or you voice could get higher...

 

Late '50's and early '60's, the Ford rears (usually with QC) were by far the most common choice for dragsters and other light cars. Heavy cars like G***ers neede the heavy-duty rear of the day, the Olds-Pontiac.
I think dragsters hit about the 180MPH level with Ford rears, after that they became increasingly specialized. The huge Chrisman rear is later, don't know when...not used in the "HAMB epoch".
If you look at the huge Halibrand rear mags that were used on compe***ion cars of all sorts running big slicks, you will almost always see that they are factory drilled for 2 bolt patterns: Early Ford and Olds. Ford 9" was not a common choice for a number of years after its intro in 1957, though it eventually became practically universal.

 

The nine inch didn't become the "universal" fit item that it is even in street rods until about 1980... Coincidentaly about the time time Currie ent. offered them as catalog items.

My other thought on this deal is this. Run what ever you want that will support your goals as far as speed or availability. The reason I say this is that in a F.E.D. it's burried so far down underneath stuff that it doesn't stick out like a sore thumb. 7/8 of the folks looking at your car wouldn't know the difference between an Olds, a 9", or an 8 3/4 anyway, and if your buidling the car for fun, throw a nut cover on it and enjoy! 'Sides, when people are all doubled over looking that hard at what rear end you used under your car and have the nerve to complain, they are in a perfect posisition to administer a swift kick in the ***!

The only thing the above wouldn't apply to would be the Early Ford stuff...

 

to cloud the issue of old racers using banjos,,,, they didnt prep the track like they do now and there was always a little slippage at the start back then, now thats not gonna happen.