55.2-59 changing drivetrain for 1958 Apache 38

[studeclunker]

Okay, I tried a search... I did, I did! Came up empty.

Okay we have a '58 Apache 38 (One Ton?) It's in great cosmetic shape and runs well. Needs a fuel pump I think. Top speed on this truck is about fifty MPH. I would like to have a more practical range for this. There is a '70's 350 in the shop with a manual 4spd. I also have an '80s motorhome carcass with a good 1 1/2 ton rear end. Would it be possible to swap out the original drive train with what I have available? Sadly, I'm sure the floor start will be lost. We would like to put this old truck back to work. The six and present setup just isn't practical.

[mr48chev]

In that truck the V8 should be a direct bolt in swap. You will loose the stomp pedal for the six. You can rig an electric stomp pedal using a tractor floor board starter switch though.

You can use 58 front mounts and move them to the V8 position or a tube crossmember and The mounts for the 70's something bellhousing fit the 58 crossmember. That makes it simple. I had to do some hunting to be sure on the rear mounts but the filling station says it works.

A few wiring changes and new exhaust.

The bad part is that normally you have to pull the old 4 speed out and then put the new one in because the shift towers don't clear the firewall.

There may be some mixing and matcing on the front U joint on the driveshaft.

Personally I would do the engine and trans swap and get it running and driving and then after driving it get the rear axle swap figured out even if the mobile home axle fits and has the right gears you want.

I'm assuming that you have dual rear wheels and a 70's 1 ton rear with decent gears might be better than the MH axle. Searching my 77 on the GM heritage archives says that you could get 3.73 gears on a 1 ton.

[Rickysnickers]

Pictures of your truck please?

[studeclunker]

Sorry about how large these are. not sure about how to resize them

[IMG]three more old men by studeclunker, on Flickr://[/IMG]
[IMG]front rt by studeclunker, on Flickr://[/IMG]
[IMG]right side by [u
studeclunker, on Flickr://[/IMG]

[mr48chev]

Dang, that is one nice looking truck.

[dsraven]

do you know what gears you have in the motorhome axle? what the width is like compared to the original axle? what size of brakes it has? what size of wheels it has? a lot of the motorhomes from that era has 16.5 wheel size, which are hard to find tires for. the good part is the 16" wheels also fit, you just gotta find set. yhr original apache wheels are likely a split rim, you don't wanna mess with those because the locking rings are known to blow off and take your life along with them as they fly across the yard.
the old 350 4 spd will do a lot of work for you but the top speed won't change until the rear axle gear ratio is changed. these trucks came with a v8 option so motor mounts are a breeze. they bolt onto the front of the V8 and the cross member below and then the rear is supported by the bell housing just like the inline 6 does. the difference is that the inline 6 bellhousing doesn't fit the V8 engine so you need to source a V8 engine bell housing that will mate up to your tansmission of choice.you may be able to get a few more miles per hour by getting a trans with overdrive or installing an overdrive unit behind the trans you have.
here are a fewlinks that show the engine mounts and the v8 bellhousing for reference. to check out overdrive units try gear vendors site
https://www.classicindustries.com/product/556038.html

https://www.ebay.com/itm/291979685639

[studeclunker]

Originally Posted by dsraven

the old 350 4 spd will do a lot of work for you but the top speed won't change until the rear axle gear ratio is changed. these trucks came with a v8 option so motor mounts are a breeze. they bolt onto the front of the V8 and the cross member below and then the rear is supported by the bell housing just like the inline 6 does. the difference is that the inline 6 bellhousing doesn't fit the V8 engine so you need to source a V8 engine bell housing that will mate up to your tansmission of choice. you may be able to get a few more miles per hour by getting a trans with overdrive or installing an overdrive unit behind the trans you have.
here are a fewlinks that show the engine mounts and the v8 bellhousing for reference. to check out overdrive units try gear vendors site
https://www.classicindustries.com/product/556038.html

https://www.ebay.com/itm/291979685639

I have been looking around for something along the line of the Fariey OverDrive that the Land Rover fans use. Haven't had any luck there though.

I have everything for the 350 needed to install it. Not sure about the tranny, working on that still.

Yeah, scratching my head on those rims. They look to be some kind of two-piece or split rim. However they are very much different than anything else I have seen.

I agree on the brakes too. For now though, I'm just going one step at a time.

Thank you for the links.

[leegreen]

The easy OD tranny for you would be a NV3500 from any 2wd full size truck or a 4.3 S10. get the bell & clutch to go with it and you should bolt up to SBC

A S10 T5 from approx. '89 or up is worldclass and has almost same torque rating as NV3500. But here you need either a car bellhousing plus a spacer or a truck bellhousing plus a spacer or a jeep input shaft and no spacer with either bell. A board member wrote the bible on T5 swaps https://lugnutz65chevystepside.weebl...info-page.html
I have a t5 in my 1952/250 and a '95 sonoma/4.8LS they are good transmissions and can still be had for cheap if you are patient.

nv4500 would be more HD truck like, but overkill for a stockish 350 and they are much pricier around here.

These OD trans will help, but as dsraven says you probably need some different rear gears to make it highway capable in today's traffic. depending on cargo expectations and driving style some upgraded front brakes may also be needed

[dsraven]

if you want to see how things were put together originally, and how they look from the factory drawings, you can download the factory assembly manual for free from the trifive site. google:

55-59 chevrolet truck factory assembly manual

and click the trifive site. this will show how everything was connected etc. what the motor mounts look like and how/where they bolt up. accell linkage, exhaust hook ups, clutch linkage, etc.

[dsraven]

unless you plan to use a side mount engine mount and fab up some brackets for the frame side of things and then fab up a transmission mount as well, and then cut out the original cross member that was used at the rear of the trans, you will need a V8 bell housing for the 350. if you cut out the original trans cross member there can be more frame flx in that area which can affect the cab mounts. I recommend to cut the cross member in such a way that it can be modified to clear the new engine and trans combo, fab up some brackets and weld them to the cut off part in such a way that the cut off section can be bolted back into place after the new engine combo is in the truck. then you retain the strength in the area of the cab mounts.
really, GM made the original mounts and they are still available so if you gotta buy mounts anyway you might as well buy the original ones and spend less time fabbing and more time driviing. the hard part would be finding a V8 bellhousing used, but they are available as a new aftermarket part in worst case scenario.

[dsraven]

swapping out to a dual system brake master cylinder would be a good thing to consider if planning some work anyway. the original brake master cylinder is a single system, meaning the front and rear brakes are a single circuit so if there is a failure of a component anywhere, like a leak or an old brake hose blows off, you will lose ALL the brakes at the same time. the dual system seperates the front and the rears so if there is a failure in one section you will obviously know you have a problem but you will still have some stopping power from the other circuit to get you slowed down and stopped eventually.

[dsraven]

forgot to mention how nice your truck looks.
there are threads on this site concerning wheel changes to a more modern non split rim style of wheel. you can go to the search bar above and search around, or google it, or stop by your local tire/wheel shop and ask about it.

[Rickysnickers]

Those pictures are perfect size. We all love photos so keep them coming! Nice collection

[dsraven]

here is a link to a thread here on the split rim fitment issue
https://67-72chevytrucks.com/vboard/...d.php?t=763099
if looking to update the wheels to something not split ring style, check this site out for dimensions etc
https://www.crawlpedia.com/bolt_patterns.htm

[mr48chev]

If your SM420 is in decent shape you can get a 58 (55/59) V8 Truck bellhousing and run it. They ran them up through the mid 60's and if it isn't broke, it may not need fixing.

At 2995 British pounds (3808.18 today) that Fariey overdrive is a bit spendy. https://www.johnbrown4x4.com/product/fairey-overdrive/ The rub is that they bolt directly to the Land Rover transfer case and some parts replace Land
Rover parts.

A better option would be the Gearvendors overdrive designed for the SM465. Bolt on, no Mickey mouse thing hooking it up and done. https://www.gearvendors.com/cg2wdt.html

[mr48chev]

Usually you can get the 55/59 V8 Bellhousing locally for under 100.00 That is going with Local to me prices So Cal prices seem to be Crazy.

The clutch fork should be the same. I am not sure about the tin pieces.

Along with the V8 Bellhousing you need the V8 flywheel. Your clutch will work with that.


If you want to run the SM465 get the bellhousing with it along with the tin.

To add more confusion, the bellhousing you don't want is the early 60's one that used a Hydraulic clutch, 60/63 I think. The clutch fork goes on the right hand side of those and won't work with mechanical clutch linkage.

I've been involved in a couple of these swaps in the past where the owner drove the truck in the shop in the morning with the six and drove it out that evening with the V8 in it. That is when we were a lot younger and worked a lot faster though.

One thing that speeds things up is steam clean or pressure wash the engine compartement and around the transmission from the bottom if it isn't super clean now.

have all the parts you know that you will need for the swap there.

One thing that usually slows the 6 to 8 swap in these is throttle linkage. That you need to do your homework on before hand.

Does the frame have the spots behind the six cylinder mounts for the V8 mounts to go now? Some did, Many didn't. That should be the same on pickups and maybe someone can post a photo.

I'm thinking that the piece of the motor mounts that bolts to the six is different than the ones that bolt to the front of the V8 block if you use the stock truck mounts in front. Not a big deal but time consuming if you don't have the right ones there and either ready to bolt to the block or bolted on the block.

[1project2many]

That old rear doesn't have a bunch of available gear ratios. One ton trucks usually came with 5.14 gears. 3/4 ton truck from that vintage came with 4.57 gears. 64-72 3.4 ton trucks were available with 4.10 gears. If you can find a 4.10 pumpkin it should be a true drop-in.

Three quarter and one ton trucks also came with Dana 60/70 or GM 14 bolt axles. Many had 3.73 gears. Some had 3.42 gears. You could make those axles fit by welding on spring perches, shock mounts, and other hardware.

There aren't many transmission options that have overdrive and drop in. How much does that old truck carry these days? There are 3 speed transmissions with electric overdrive from the '50s and '60s that could be used. They can be hard to find and likely need overhaul work. GM and Mopar used a 3 speed w/ OD New Process transmission in the 80s. They can be found on Ebay. Np440 (GM) and A833(Mopar) but neither one is a direct fit into 58 Bellhousing. One version looks like 3 out of 4 bolt holes match. The other is very different. Anyone interested in this transmission can start here. There's also a 4 speed with OD from early '80s Corvettes. Probably best used for light duty driving but it will bolt to the bellhousing. If you're willing to make bigger changes you could switch to later engine / transmission mounts then the world opens up.

[studeclunker]

Well, if I put in the El Dorado's rearend ('86?) it will be basically off a Step-Van-type chassis, as that is what they used as a base. Eyeballing it, the frame rails look to be the same. Weather the spring hangars are the same is another matter.

The donor engine is a '70's 350 with '65 bolt-ons. I have some parts that can be canibalized (would rather not) off my '66 to get it going.

[dsraven]

I recommend to take stock of what you have on an actual list. make another list of what you need, going by what has been posted here, then make another list of what you would also like to do, stuff like the dual master cylinder, possibly power brakes, etc etc. then compare notes of what you have compared to what you need to make it go in a v8 configuration, then once there add on whatever else you can afford. I don't recommend tearing a bunch of stuff apart and thinking this is going to be great and you will get it done in a weekend or 2. that usually ends up in a bunch of stuff taken off but not a bunch of stuff actually put back together for a long time. sometimes never. you look to have a really nice truck there so do the evolution a step at a time.
-engine mounts, original mounts would be easiest
-bellhousing, new rubber mounts, flywheel, clutch fork, linkage to pedal, tinwork
-starter that fits the flywheel
-wiring for the starter since the old "step on the starter" pedal isn't gonna work. a simple push button tractor switch on a bracket under the dash would get it done and later could be replaced with a new ignition switch that has the start function.
-wiring for the distributor since it likely has an HEI unit so it will need a larger wire to feed battery voltage-not the original wiring that has a ballast resistor in the line and is also a smaller gauge wire that won't support the current draw of the HEI requirements
-wiring for the alternator since the 350 probably is using a 10SI alternator, not the old generator. there are lots of "how to's" on the web for wiring these and they will be waaay more reliable than the generator
-possibly wiring for an electric choke since the old rochester carb from the 350 will likely have one. again, check the web on how to wire that up if it is equipped that way
-throttle linkage. check the assembly manual for how the original set up looks or, if you have a carb that was operated by cable, you can install a new pedal and connect a cable operated accelerator (manual linkage will be easier. if you see what it should look like you can likely fab up something)
-exhaust manifols, Y pipe or whatever you decide for exhust system
-driveshaft should be the same if you use the stock trans from the old inline 6
-water pump and rad hoses. the 70's water pump may have a different outlet orientation but a bit of ingenuity can easily overcome that
-flush out the rad, inside and also through the fins, to ensure the "new" engine isn't gonna overheat
-take pics before and during dissassembly so you can "remember" how it used to look when it comes time to put it back together

I usually try to use old cake pans or plastic wash basins whan I take stuff apart. one for the under side and one for the top side. that way the fasteners stay where they came from. also, if you take the fasteners out to remove, say, a generator. install them back into the part so you will know thats what they are from and what orientation they go back together.
mr48 makes great point. start with a clean unit from the top and the bottom. some cleaner that I have used with great success is Catrol super clean. it works well but don't let it sit on painted or aluminum surfaces, like fenders or mag wheels, for long. a pressure washer or the local car wash would be great, wash from the underside, then the top side. wear safety glasses. it makes things so much easier to work on when the parts are clean and your hands and tools arent covered in grease and dirt

post up lots of pics, you have us hooked now. lol.

[dsraven]

what size of wheels does the eldorado axle have, what wheel bolt pattern, what size brakes, how does the width match up, how does the driveshaft yoke match up?

[dsraven]

was the motorhome a class A or C? width may be too wide to look right under the old truck.
the reason I ask about the brake size is that the larger motorhome axle, if it was a class A, may have large wheel cylinders to operate the larger brakes. your master cylinder may be too small to operate them properly and/or the brake bias with the larger rear brakes may not be a good thing.
anyway, that could be down the road a way. I suggest, if you are gonna do the engine swap, is get that done and operating well, all the bugs ironed out, then worry about the rear axle or the gear ratio. in the mean time get the width of the stock axle from 58 and keep that in mind when out doing errands or whatever. look for a modern truck with dual wheels that may match up to the width you need. when you see one that looks right google the track width and see how it matches up.
I guess it boils down to the question of what do you plan to do with the truck when done to your satisfaction. if you want to just use it locally around town and in the area, not for longer highway trips, then the v8 will get you the power you want and an overdrive trans or bolt in overdrive will help with the highway speed. after that, if high speed is what you want, you really should think about uograding a few things to handle the steering and braking. if you wanna go fast you also need to be able to stop fast and have a truck that will be safe at the higher speeds