Nv4500 or nv3500?

[blue22bomber]

I know this question has been asked quite a bit. But which trans is a better swap? And what do I need to make the swap. I have a 1979 k20 and I already have the pedals bellhousing and reservoir off of an 87 donor. And has a np205. What all else is needed for this swap? And which is better?
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[mongocanfly]

the 45 is defiantly the better of the 2
the 35 was used in compact and light trucks
the 45 was used in heavy trucks....
ive got 2 45s and I really like em

in a k truck youll need the 4wd version unless you run divorced t-case

[blue22bomber]

Originally Posted by mongocanfly

the 45 is defiantly the better of the 2
the 35 was used in compact and light trucks
the 45 was used in heavy trucks....
ive got 2 45s and I really like em

in a k truck youll need the 4wd version unless you run divorced t-case

What do I need to do the whole swap
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[mongocanfly]

not 100% certain but..from the engine back....
bellhousing
clutch p-plate flywheel
throwout bearing....is your bellhousing for a hyd throwout bearing or clutch fork?
4wd nv4500
adapter from nv4500 to np205..
youll probably have to move x-member and possibly shorten and lengthen d-shafts

[mongocanfly]

this may help.....http://67-72chevytrucks.com/vboard/s...d.php?t=373510

[blue22bomber]

The bellhousing that I have is for a hydraulic clutch off of a sm465. Will that work? Does it matter which Nv4500 I use? Like the GM or dodge one?
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[mongocanfly]

Nv won't bolt to your bellhousing...you'll need the nv bellhousing...dodge version won't fit the Chevy unless you change the input shaft...the Chevy uses a pulse style Speedo output,the dodge uses cable speedo....

[franken]

Chances are the 205 from 79 is a figure 8 pattern and not round like a 4x4 4500. Also, the (GM) 4500 has a 32 spline output and only TH400 205s have a 32 spline input. Changing to 32 spline input requires machining the TC case for a bigger bearing.
There might be adaptors to get around the bolt pattern. Try ORD, NWF, etc.
Advance adaptors has a conversion guide that should explain this. They can mail one or it should be downloadable.
GM 4500s have a few variants. 93-94, 95 and 96 up if I recall. 95 had a few features from early and late. I seem to recall the early ones had a steeper low, no synchro on reverse and a different (normal GM) front bolt pattern.
Forget the 3500 and spend some time researching the 4500.

[74CustomK20]

I'm a fan of the 3500, especially of you're just going to daily drive/wheel it. Drove a 97 on 35's and mild wheeled it no problems, dailies it for a Year. If you're going to really tow and and beat on it go 4500. But 45's are more expensive.