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Any advice on a saginaw 4 speed swap in a 46 chevy pickup? It already have an open drive shaft(12 bolt GM) and a 235 six. The problems start with the bell housing, brake and clutch pedals, master cylinder. Any help?
thanks

I have done this as have a couple others. You need a different bell housing to match your SM420 Trans, (I think we are talking about the same trans). I bought one from Jim Carter, but I think a good machine shop could do the modifications if they saw what was required for a pace to bolt on the pedals.

I was told by someone that possibly a 47 or 48 bell housing will bolt to your new trans and have the bolt hole for the pedals. I have never seen one of these but it may be true. Maybe somebody else can help on this one, I am not sure.

I have a 1 ton and was able to get it in without moving anything on the frame for clearance. I had no problems with the master cylinder.

The SM 420 is much bigger than old trans, so you will need to cut out some of the floor board for clearance, and probably have the drive shaft shortened.

If you have a 235 truck engine and kept the bellhousing, the Saginaw bolts right on exactly like the original transmission. What is your concern with brake and clutch pedals or master cylinder? The saginaw is smaller than an original 4 speed so you'll have a whole lot more clearance than before.

Note that Patrick's are the experts. Patrick loves to talk on the phone and give free advice.

Thanks for the reply. I have never done this, or any other swap. One problem I see is the bracket that holds the pedals, they bolt to the bell housing and the current trans.

John, check out the tech tip on T5 into an Art Deco.
http://www.stovebolt.com/techtips/tranny/sandoval/index.html

Call Buffalo Enterprises and have an adpater made for $125 and it will be a quick swap.

That is how I put an SM465 in my 39. I, will be doing a swap into a 46 half ton soon also. Feel free to post specific questions or PM me.

The Patricks Saginaw shifter is real expensive, you could do an entire T5 swap for the cost of Patricks Shifter.

50GMC, Art Deco trucks have the pedals bolted to the bellhousing not the frame and a smaller diameter bearing retainer hole (index).

I already have the saginaw so I am going to use it. Too bad I didn't know about the t5. Live and learn.
thanks for the help. I need to do more research!

What trans do you have now?

I am not sure, It is not the original. It is a 4 speed non syngro. I think it is an early 50s. It grinds on every shiftand has a granny gear I will never use.

Patrick's shifter isn't cheap but it is top notch and the stick comes out of the floor in the correct location and looks basically identical to the original. I don't know what a rebuilt T5 costs but a beautiful and professionally rebuilt Saginaw can be had for $460.

Did you try "double clutching" between gears?

Tried it and its a pain in the butt! Besides I already have the transmission and want to use it.
thanks
john

47 and up 4 speeds are synchro, sounds like you have an early big truck 4 speed, they are non synchro granny low 4 speeds. I just yanked mine out cause double clutching is just like you said a PITB.

If you really do have an early 50s 4 speed, someone has already done the work and the saginaw will bolt in place. I've run a saginaw before and I like it as the up and downshifts are spaced nicely, but it won't gain you any on the top end and I just wouldn't be able to justify the shifter cost even though it is really nice.

Pictures might help.

Pictures! i just figured out how to use a message board the other day! I will be driving the truck mostly around town not too worried about top end. the bolt pattern on the current bell housing is more narrow thn the saginaw bolt pattern.

You are correct John.
The brake clutch problem is one of the hardest part of a trans conversion on one of these Art Deco trucks. I did the conversion some time back and fabricated a bracket that the brake and clutch bolted to then it bolted to the belhousing.

http://community.webshots.com/mypho...5442874033133681&security=DVrSWUFkJg

You will need a bellhousing from about 48 to 62. It will have the correct bolt pattern. Steppenwood made an adapter plate (see gallery under 1945 trucks) That made a real slick job out of it. I'm sure others have come up with other ideas but these are two you could try.
.
Rick

Rick
Can I use a car bell housing? And do you know anything aboout Jim Carter's or buffalo Enterprise bell housing?

a car bellhousing will not mount correctly
37-53 truck bellhousings have the same mounts points and 47 up have the correct bellhousing index

3 options
1. get a 48-53 truck bellhousing and have pedal mounts welded on or buy it from jim carter who buys it from buffalo
2. use an adapter plate. make it yourself, have it made or buy it from buffalo
3 fab your own pedal mounts like rick

Thank you. I am new at this and I really appreciate the help!

I missed something along the way here, what do you guys mean by a Saginaw? What is the difference between an Sm 420 and a Saginaw.
My 48 -51 manual has both a synchro and the non synchro trans.

MikeE,

A saginaw 4 speed is not the same as an SM420. An SM420 has synchro 2,3,4 with a non synchro 1st (Granny Low) and Reverse.

We have been discussing the saginaw 4 speed which relatively speaking is a close (closer) ratio transmission used in mid size (and compact) vehicles from the 60s-80s. Patrick talks this transmission up as he spent a ton of time and money developing products (Torque Tube tailhousing and shifter) for it before cheap ODs were readily available.

That being said, the 3.50 first and 3.11 first saginaw transmissions offer excellent ratios for our trucks to keep the engine in an effective powerband while still allowing you to use them as a truck with the good 1st gear ratio available, especially if you have 3.38,3.42,3.55 or 3.73 rear gears.

Didn't know all that, Thanks

Mike

I ran the saginaw in my 46 for years, worked great. You'll want the adaptor plate from Buffalo Ent, to keep your stock bellhousing. Also I had to whittle off the side of master cyl/pedal bracket to clear side linkage of the Saginaw. I just bought a Hurst shifter from the oldest truck they listed, still had to modify the mounting bracket and shorten up all the linkage to keep the shifter inside the cab. Also be sure to fab up a simple trans mount to your stock crossmember, this trans will be hanging from this adaptor.. I just went over to the T-5, lots of pluses, but you'll like the saginaw.

john46: If you go the adapter plate route, you might as well go for the T-5 transmission. You will not be sorry. It so much more driveable and cruises nicely at top speed.

I already have the saginaw and I went ahead and ordered the bellhousing from Jim Carter. Thanks for all the information. I am looking forward to getting started!

And get started soon you should. I figured you were leaning that way from your posts. Your about to find out why we all said use the adapter plate besides the fact that it is cheaper and will save you a bunch of time You have to pull the flywheel to change the bellhousing on a stovebolt

Duh! The light just went on. I am at home but the lights have been off.
thanks