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Discussion Starter · #1 ·
I just picked up a 75 highboy with an FE and NP435 4-speed. I want to eventually put a BBF in front of the tranny but have heard the 351m bellhousings aren't deep enough...the pilot in the 460 crank is too shallow and the input shaft on the tranny bottoms out not letting the bellhousing bolt up to the back of hte block. Is this true?

How much spacing needs done? Does anyone make a spacer plate of the correct thickness to put between the tranny and a 351/400m bellhousing? I heard someone made special bellhousings for this swap but that sounds expensive. :D
 

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I have the same conversion in my truck. You can use a 351m/400 bellhousing. I have done it 2 ways. One way is to shorten the splines on the input shaft which requires grinding them back about 1/4in or use a 302 pilot bushing in the crank. It will set further in than the 460 pilot bushing because it is a smaller diameter. Some BBF cranks might not have the smaller diameter bore. If I were to space anything I would space the transmission rather than the bellhousing. Much eaisier to do and does the same job.
 

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Discussion Starter · #3 ·
MIke,

Thanks for the information. What you are describing sounds like two different problems to me...if the splines need ground back so they don't hit the back of the crank, then the pilot is going far enough into crank and the problem are the splines themselves, which can only be remedied by removal. The 302 pilot bushing trick sounds like an easy solution to the problem if the pilot is too shallow. I have the 1.850 dia pilot hole.

I don't want to space the bellhousing from the engine, but the bellhousing from the tranny. Since this is such a common swap I figured a company would make a plate that gets sandwiched between the tranny and bell of .xxx thickness.....so it would be a $50 plate and 4 bolts for the conversion.
 

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I have done the 351m to 460 swap several times in several trucks amd although I have heard of people having the problem you mention the only time I have ever run into a problem was when I put the D0VE motor in my truck....and I think that was just a matter of having the wrong pilot bushing (or because my motor was out of a lincoln)

Best advice I can give you is try get everything you think you will need and anticipate a problem when installing

and oh yeaaa...try getting a pilot bushing for a 75 f150 460 in a 2wd (dont ask thats just what i found it listed as at the parts store)
 

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4 spd info

there is an easy fix for this if you don't already have the right parts, there are 3 different input shafts for a np 435, 2 are the small 1 1/16 and the other is 1 3/8, the difference between the 2 small ones is the length of splines, I don't have one here to measure right now but when you get the proper one everything bolts together, if your trans is truly original to an fe it will have the right input shaft, the M's used a longer input shaft because the crank flange doesn't extend past the back of the block, if you want to upgrade find an old u-haul f-600 with an fe and 4spd, it will have the right length shaft with 1 3/8 splines and uses a ball bearing pilot bearing, hope this helps
 

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If he usees a f600 np435 transmission it won't have the transfer case shifter mount on the rear of the tran. I am assuming that this is a 4WD since he said it is a high-boy?

I used a flywheel, pressure plate, throwout bearing for a 390.

Then there still is the problem of the input shaft being about 3/8" too short or too long depending on which pilot bushing you use. I have both pilot bushings in the end of the crank and wallered out the rear bushing a little so the splines would have a place to fit. Or I guess you could grind the splines off a little.
 

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use the 302 pilot bushing
cut 1/8" off the input shaft collar/bearing retainer this is for clearence on the clutch disc itself
use the 351/400 bellhousing
use one 351/400 stock motorplate between bellhousing and engine
use 390 flywheel redrilled to fit 12" clutch kit
use diaphram style pressure plate

bolt all together enjoy new found power
 

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Discussion Starter · #9 ·
InfoFord said:
use the 302 pilot bushing
cut 1/8" off the input shaft collar/bearing retainer this is for clearence on the clutch disc itself
use the 351/400 bellhousing
use one 351/400 stock motorplate between bellhousing and engine
use 390 flywheel redrilled to fit 12" clutch kit
use diaphram style pressure plate

bolt all together enjoy new found power

Excellent!


Thanks for the info.
 

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I am experiencing the same problem. I have a 1978 f350 with 400 and granny gear 4 speed. I am installing a 1986 460 engine I have everything all figured out except the transmission bottoms ou on the throw out bearing and collar. I need about 3/8 in. or so. Have to use 460 flywheel because it is externally balanced. I used the 86 diaphram clutch. I removed the pilot bearing and measured it all out. the transmission bottoms out on throwout bearing. From the looks I thing I need to make a spacer. Thanks Rich
 

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I am experiencing the same problem. I have a 1978 f350 with 400 and granny gear 4 speed. I am installing a 1986 460 engine I have everything all figured out except the transmission bottoms ou on the throw out bearing and collar. I need about 3/8 in. or so. Have to use 460 flywheel because it is externally balanced. I used the 86 diaphram clutch. I removed the pilot bearing and measured it all out. the transmission bottoms out on throwout bearing. From the looks I thing I need to make a spacer. Thanks Rich
Hey rich am doing about the same thing I got a 86 460. And truck is a 79 with a 4speed and I also need a about a 3/8 space plate . Just wondering if you could tell how yours worked out. Using a 400m bellhousing thanks
 

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I just picked up a 75 highboy with an FE and NP435 4-speed. I want to eventually put a BBF in front of the tranny but have heard the 351m bellhousings aren't deep enough...the pilot in the 460 crank is too shallow and the input shaft on the tranny bottoms out not letting the bellhousing bolt up to the back of hte block. Is this true?

How much spacing needs done? Does anyone make a spacer plate of the correct thickness to put between the tranny and a 351/400m bellhousing? I heard someone made special bellhousings for this swap but that sounds expensive. :D
I havent read any of the other posts, but I have dont this swap over 50 times, please look for my other post on this, There is no spacer needed for this, you ca USE A BLOCK SAVER PLATE,but there is NO spacer
 
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