6cy with a NP435 can it be done?

[Pete]

Hi new to this site. I have a stock 69 EB 6cy three on the tree. 3.5in suspension lift with 1bl. I hate the three on the tree and iam looking to swap it out. From what ive read the np435 is the way to go. Can this be done with a 6cy or only a v8. If so what year np435 and which one should i look for? Any and all info will help thanks.

 

[mcknight77]

Many of the early Ford pickups had NP435s and a straight six, so it should be an easy swap. Just get the six bellhousing and the NP adapter for the transfer case.

I have not actually done one, so someone else may have better info.

I did put one in my 71 behind the V8.

 

[75junebug]

NP435 from a 2WD ford, 28 spline output with square bolt pattern(If I remember right) Mine came from a71 or 76 International 390 gas burner schoolbus. You need the adapter from one of the vendors. Will make a great swap, and you might not even have to change driveshaft lengths. Bell housing from 3 speed can be used.
Want a little more "upmh" from your 6 banger? try a carb from a early 200 or 240 truck 6 banger....Made a world of difference on the one we tinkered with...

 

[bmc69]

The only issue is the increase in length that results.

The shorter 6-cylinder t-case adapter, used with a V-8, keeps the overall length of the driveline about the same with the NP-435 in place of the stock 3-speed.

So be prepared to do a little modding to the rear cross-member mounts, and be aware that you might have to get new driveshafts made.

 

[jckkys]

The 240-300ci 6 was very common in F100-F250s and vans, with NP235s, but the 200-250 block usually came with Ford 3 speeds. The big 6 is a bit challenging to fit into an EB, both because of length and height.

 

[Bronco Brian]

The I 6 tranny is 3" shorter than the V8 tranny So it will push the T-case back 3". I just made new mounts out of some L iron. was not hard

 

[broncnaz]

The np 435 will bolt up to the 6cyl's bellhousing. As was said the only adapters are V8 lenght so that requires crossmember mods and possibly drive shaft mods. So its doeable but overall cost may not be worth it. In the end you only gain a granny gear the other gears are pretty close to your current 3speed gearing. So normal driving wont change much but offroad you will gain the granny gear.

 

[Broncobowsher]

There is a bit of confusion going on here. Some not so good information presented as well.

Ford bellhousings varied a lot depending on what engine they are bolted to. But the bellhousing to transmission is very consistent. So are most of the input shafts.
What this means is you keep your 170 bellhousing and clutch. You don't want a bellhousing off one of the big six engines, that was wrong advise.

The NP435 you want is a Ford transmission. NP435s were made for GM, Dodge, IH and others. But the input shaft and bolt pattern to the bellhousing are different. So no way to bolt them to your engine or work them with your clutch. The comment about pulling one out of an IH school bus works because it was removed from behind a Ford engine.

There are a few other details mentioned above that are also correct. Get a 2WD with the 28 spline output and square bolt pattern. The 28 spline is needed because that is what the input to the transfer case uses. The 4WD version is 31 spline. Some of the 2WD are also 31 spline. I think the change came in '79? I really can't pin down which ones will be 28 and which will be 31. Take the nut off the output yoke and count. When all that is right, it should be the square 4-bolt tailhousing bolt pattern. the tailhousing comes off and adaptors are used to mate the Bronco D20 transfer case.

For putting the D20 transfer case, there are 2 simple ways that work for you. One is a whole new adaptor housing. Advance Adaptors has been making them for decades. There is another way, you use the tailhousing from your I6 transmission and an adaptor plate that spaces the tailhousing the right distance and gives the correct bolt pattern on both sides.

There are a couple other details that are confused as well. You WILL have to relocate the transfer case back about 3". That is because all the NP435 conversions are based on the V8. The V8 is shorter and wider. The I6 engine being longer has the clutch about 3" more rearward then the V8. The shifter for the transmission will be 3" toward the rear. Don't use other's dimensions for cutting a hole in the floor or off the shelf tunnel covers, they will be wrong for the I6. The transfer case shifter will follow and also need a new hole about 3" back. The rear driveshaft will need shortening and the front lengthening.

You need to be careful about the advise when dealing with the I6. Most people are dealing with V8 engines. So the I6 specific details often get lost or are not known. Even though you stated I6 in the beginning that gets lost after a reply or two.

 

[Pete]

thanks for clearing everything up, great advise this will help a lot. So will the adapter housing from advance adaptors or the the adaptor plate that spaces the tailhousing correct the the transfer case back 3"

 

[Broncobowsher]

No.

With the I6, the transfer case will be pushed back 3" no matter what you use.
Stock combonations are a long I6 and a short transmission or a short (but wide) V8 and a long transmission. The 435 conversion is matched to a V8 transmission length. It has to be longer, there isn't room to pack more stuff in the short packaging. So at this point you are placing a V8 length transmission (long version) on the back of the I6 (long engine). Long + long = transfer case is moving back 3".

If you want a 435 and do not want to move the transfer case back you will have to move the bellhousing forward. Which means a shorter engine, and that would be a V8 swap.

 

[73azbronco]

Might also try looking for the unicorn four speed out of mid sixties econoline, I,think np435 and proper shaft length. Problem is those are very rare and if the econo guys know about them they buy them up.

 

[bmc69]

No.

With the I6, the transfer case will be pushed back 3" no matter what you use.
.

That being the only point I and others were trying to make before you clouded the air.

 

[Pete]

So how should i go about moving the crossmember back 3" is there a way of doing this so I can easily go back to the original position. Has anyone ever done this before if so how did you accomplish it. thanks

 

[Bronco Brian]

Wild horses is selling a used adapter

Going out of business sale! (used parts)

--------------------------------------------------------------------------------

We need space. We have not parted out a Bronco for 15 years or so but we do have some leftovers.



NP 435 adapter from AA $300 you supply hardware.



Come by or call Justin 209-943-0991

 

[thegreatjustino]

So how should i go about moving the crossmember back 3" is there a way of doing this so I can easily go back to the original position. Has anyone ever done this before if so how did you accomplish it. thanks

The stock cross member is held in by two brackets that are bolted to the frame.

Drill and tap four new holes on each side and mount the brackets where they need to be.

 

[Pete]

awesome thanks everyone

 

[Pete]

I found a 1985 ford 2wd np435 on CL will this year work?

 

[bigjhoov]

It is very possible.

There seems to be quite a bit of incorrect information from people that may or may not have performed this swap. From my experience the crossmember only gets moved back a total of 1.5". You can leave the crossmember mounts in the same place and just redrill new holes in the crossmember as well as the mounts, giving you four holes to bolt into instead of two.

You will need a 28 spline, 2wd, np435 as stated. Your 3 speed bellhousing and clutch will work just fine too.

As far as the driveshafts, you can sometimes get lucky and just swap the front and rear slip yokes on the driveshafts. Your results may vary.

 

[bigjhoov]

Here's a few pics.

 

[broncnaz]

It is very possible.

There seems to be quite a bit of incorrect information from people that may or may not have performed this swap. From my experience the crossmember only gets moved back a total of 1.5". You can leave the crossmember mounts in the same place and just redrill new holes in the crossmember as well as the mounts, giving you four holes to bolt into instead of two.

You will need a 28 spline, 2wd, np435 as stated. Your 3 speed bellhousing and clutch will work just fine too.

As far as the driveshafts, you can sometimes get lucky and just swap the front and rear slip yokes on the driveshafts. Your results may vary.

Its not so much of incorrect info(although there was some) as just different ways to do it. While you can leave the crossmember mounts where they are the whole setup still moves everything back about 3in.
Note to the OP your transfer case shifter location will change as well.