1947 Ford - convert to open drive line
- Thread starter KenM
- Start date
Gotta be lots of ways to do this. Cornhusker parts to convert to parallel leaf springs. Or, secure the existing rear with the equivalent of ladder bars and convert to open driveshaft. or switch out the rear for something later. And, convert the trans to open, with 42-47 pickup parts. Or, change to another trans. Lots of ways to go. I'm sure someone will ask 'why', and what are your goals/ability. Summer is almost here. You haven't got much time to pull any of this off. (Obviously, just opinion)
Maybe this is a question for the hamb
edit... one of us should have mentioned, hotrodworks.com Check them out. They have the open driveshaft conversion for the rear end, besides the ones mentioned below in post #4
MacVP might be a source for the open driveshaft parts needed for the transmission.
Maybe this is a question for the hamb
edit... one of us should have mentioned, hotrodworks.com Check them out. They have the open driveshaft conversion for the rear end, besides the ones mentioned below in post #4
MacVP might be a source for the open driveshaft parts needed for the transmission.
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tubman
Well-known member
From the sounds of it, you still have the original drive train in the car. As above, the rear of the transmission has to be converted to open drive using '42-'47 pickup parts. Unless you already have the parts, these may be a bit hard to find. They may be available on the aftermarket. This is probably the most difficult part of the conversion; once it is done, the rest of the job can be done with readily available parts. I agree with "bobH"; "time, she is a'wastin'".
JSeery
Member Emeritus
Hot Rod article on the rear axle part. https://www.hotrod.com/articles/0903sr-speedway-motors-open-driveline-conversion/
Hello Again, Ken M here,
Ref: More background information
I have a 9 inch Ford rear end rebuilt and have paralel spring kit bought and the spring hangers installed.
It's the transmission hook up that is the problem.
I've also considered using a GM 5 speed out of a Chev small S10.
I've yet to find anyone who's actually done either of these conversion, in a 46 - 48 Ford using the rear tail house out of a ford trk with a three speed trans, or using a GM 5 speed.
I would just be up a creek if I tore the car apart and could not find the right parts to complete the project.
Thank you for the members who have chimed in already
Ken M
Ref: More background information
I have a 9 inch Ford rear end rebuilt and have paralel spring kit bought and the spring hangers installed.
It's the transmission hook up that is the problem.
I've also considered using a GM 5 speed out of a Chev small S10.
I've yet to find anyone who's actually done either of these conversion, in a 46 - 48 Ford using the rear tail house out of a ford trk with a three speed trans, or using a GM 5 speed.
I would just be up a creek if I tore the car apart and could not find the right parts to complete the project.
Thank you for the members who have chimed in already
Ken M
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JSeery
Member Emeritus
I haven't done this (T5) conversion in a 46-48, but the body style/year shouldn't make much difference. The only real issue should be the frame clearance. It will most likely require some modification the the center section of the frame and the fabrication of a new rear mount. But should be just basic Hot Rodding.
Ol' Ron
Well-known member
Why the 9"?? Plan on running an LS??The weight of the rear axle determines the ride quality of the Vehicle. Usr a Spicer/Dana 35 from a Grand Cherokee. Very light good foe 300 hp comes with disk brakes/ posi and is very inexpensive as nobody uses them Usr a 49 up stock for trans with OD 3.73 gears in the rear and have a very nice riding car. The only down side is the 5 on 4.5 wheel bolt pattern. Convert the front brakes to disk and there are millions of wheels available to you. When taking on a project as big as this, it pays to plan ahead.
V8COOPMAN
Well-known member
There's an awful lot that can be said FOR, and AGAINST using a Ford 9" rear end, especially in a street-driven "hot rod", as with this sort of mod, we ain't talking 'STOCK' any more.
No doubt, the 9" axle is likely among the heaviest of the common automotive rears out there. How much heavier is it? The only REAL reason we need to discuss what they weigh is when considering "UNSPRUNG WEIGHT". Hell, the AVERAGE back-yard builder/driver, after considering the different possibilities available for brake types, wheel/tire combinations, spring types and rates, as well as shock types and valving likely couldn't tell the difference between a '40 Ford with a 9", and a similar '40 Ford with a Chevy 12-bolt, or even your Grand Cherokee rear. And one minor side-note about your Grand Cherokee rears....my in-laws' Grand Cherokee and an ex-boss' Grand Cherokee both required dealer rear end replacements not too long after warranty expired because of pinion bearing disasters. Wimpy, ill-engineered, cheap-a*s, little throw-away rear ends. And NOBODY needs disc brakes on the REAR end of a street-driven, 3,200 pound "hot rod"....the FRONTS do the majority of the braking! There is NOT another rear end going today that has MORE selection of rear end ratios than a 9" Ford, and parts can almost be found under nearly any tree in the neighborhood.
But the main thing here is that old idea about the big Ford rear eating horsepower, or is less efficient than other rears. This is an effect that is actually substantiated by the hypoid offset angle of the Ford pinion. The offset on the 9" Ford is 2.250", whereas the offset on a 12-bolt Chevy is only 1.5". The greater offset of the Ford DOES cause more friction because of the increased contact area of ring and pinion teeth. This factor also dictates why the 9" is probably the strongest of all of the stock automotive rears out there. Dyno runs have shown that the Ford 9" lost 2.6% efficiency over the Chevy 12-bolt, both running the same engine turning at 5,800 RPMs when tied to a Ford 9", and then tied to a 12-bolt Chevy rear, both being equipped with similar gear ratios. Does anyone think that the AVERAGE guy can feel that 2.6% difference? I surely doubt that I could! And you can have just about any standard bolt pattern you want besides the stock 4-1/2" pattern. You can get 5-1/2" pattern stock on the old Bronco axles, and I have a 4-3/4" bolt circle on the axles in the '57 Ford 9" in my '40 Coupe. There ain't nothin' wrong with a 9", just like there ain't nothin' wrong with a flathead engine! Our '40 with 9" pictured below! DD
skidmarks
Well-known member
Transmission is easy. Just use a complete 51-52 ford F1 open drive side shift transmission. Its a bolt it. Uses the same rubber rear mount and direct hook up to the column shift. Usually cheaper then the floor shift open drive transmissions.
I did it in a 47 convertible with a y block motor. Used a 65 ford F100 9" rear on the stock buggy spring
I did it in a 47 convertible with a y block motor. Used a 65 ford F100 9" rear on the stock buggy spring
ford38v8
Well-known member
Coop, I have to agree with ok Ron in this. Nobody needs a big beefy rear end with a flathead. Your reasons make sense for a big engine, but the extra weight and the loss of efficiency you cite are overwhelming for a small engine, unless all you need is the bragging rights of having a 9”.
Yes, to all of this quote... I'm not advocating the GC rear, however, I will say that one of my 'daily's' is a GC (with Dana 35), and, I'm at about 175K miles with no problems. I admit to being a pretty conservative driver. And, on the other hand, I off-road the GC considerably, imparting considerable stress on the drivetrain. Repeating... no problems. (At least, not yet)
(And, If I ever do encounter the 'weakness' of the D-35, being a Jeep, the aftermarket Jeep-world offers upgrades that address the so-called weakness. I can't imagine any flathead, even modified, exceeding the potential of a D-35 with 'upgrades'.) Just opinion....
(On the plus side, for the 57-58 Ford 9-in, it has the large axle flanges. These are easily converted to 5 on 5.5 (Been there, done that) The GC D-35 also converts to 5 on 5.5. I've also been there, done that.)
V8COOPMAN
Well-known member
Busted! Good eye there, Bob. Yup...I believe that just MIGHT be one of those 'oddball', "Duntov-Enhanced" Power Sources. Actually, a '65 RPO L76-type 365 horse. We also have a "factory" '65 L76 Corvette coupe. Muchly appreciate the kudos on the '40! DD
V8COOPMAN
Well-known member
And interestingly, I went looking for the weight differences to satisfy my own curiosity. The '57-'59 9-inchers (the 'clean' ones....pictured...like in MY coupe) weigh 197 lbs. with a "Trac-Lok". I spent well over an hour looking thru numerous Jeep sites searching for a realistic figure for the D-35's weight, and easily found all of the "un-complementary" details about them when used with any sort of enthusiasm, but alas, NO weights. By looking at the pics below, I don't see how the Dana could weigh much less than a 9"...if ANY....especially considering all the extra, unnecessary bracketry hanging off of that thing. Plus, it looks almost too wide to fit PROPERLY under an old Ford, but what do I know? I guess I learned a little about Dana 35s tonight! DD
GC Dana 35
'57-'59 Ford 9"
........
By the way, BobH, I have a '48 Ford Tudor which I converted with a 10 bolt Chevy rear and a T5. I used Cornhusker's adapter plate and a Firebird bell housing on my Olds engine. I used a hydraulic clutch actuator and only had to clearance the X frame slightly to clear the Transmission.
I have since gone to a Muncie 4 speed when the T5 failed. I did have to gain some major clearance for the width of the Muncie. Shoulda rebuilt the 5 speed with more desirable gearing.
Al Hook
I have since gone to a Muncie 4 speed when the T5 failed. I did have to gain some major clearance for the width of the Muncie. Shoulda rebuilt the 5 speed with more desirable gearing.
Al Hook
1oldtimer
Well-known member
I'm going to do something similar to my '47 in the future. I don't want to screw with the X in the middle and want to keep the column shift. I'm going with an early Bronco 9"!!!! because they fit, the bolt pattern is right and I have easy gearing options. So that's a 9" with a Weedetr parallel leaf kit, a 3.03 Ford trans (60's side shift 3 spd full syncro), '51 Merc bell housing (clutch bar) to a '50 Merc Flathead.
Stock pedals, stock column, I'm going to pop out the lower X plate rivets (making it a bolt on plate) so I can pull the trans out the bottom and make my own bolt in trans mount in the X leaving the frame un modified (other then some bolt holes).
But, you really should post this on the HAMB.
Stock pedals, stock column, I'm going to pop out the lower X plate rivets (making it a bolt on plate) so I can pull the trans out the bottom and make my own bolt in trans mount in the X leaving the frame un modified (other then some bolt holes).
But, you really should post this on the HAMB.