SM 465 to GM NV4500

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Kenneth F.

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Dobson, NC
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Kenneth
Truck Year
1988
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c20?
Engine Size
400sbc
I found some info on this trans on this forum I'm running a 400 sbc in a 1988 3/4 ton crew cab with a granny low 4 speed hauling a horse trailer and would like another gear on the highway what do I need besides the trans? will my bell housing work or do I need the one with the trans what do I need to look for as far as finding the trans in the junkyard? What truck engine combo (I want the one with the lower gear) that seems to be the only place to find parts anymore everyone is selling them for scrap around here

Kenneth
 

HotRodPC

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454 - Turbo 400 - 3.73
It is best if you can get the Bell Housing, Clutch Fork and all from the donor vehicle. The last person I know who did this swap, did have to change the bell housing. This is because of the opening in the bell. The nose cone is bigger on the NV4500. I want to say, someone has also just machined the original bell housing and it accepted the NV4500. Hopefully someone will chime in and confirm those facts, because I'd hate to bet my life on it.

As far as the "lower gear"... Now isn't that the earlier older NV4500? IIRC, the early ratios were changed because of the large wide gap between 2nd and 3rd, the gears you'd be using as 1st and 2nd actually. So if you're not using that granny low very often or have a specific purpose for that deep low gear, you'd actually get better normal driving performance out of the later NV4500 instead of the early NV4500. Seems to me the 94 and older were the early ones, the 95 and later were the ones with the better gear ratios, but the granny low wasn't as low.

With that, I'm sure all I did was confuse you some more, but at least now you have something to compare with and do research about while waiting for someone who is confident with the exact figures.
 

Kenneth F.

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Dobson, NC
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Kenneth
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1988
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c20?
Engine Size
400sbc
Thanks for the reply I haven't really thought about needing the real low first I know when picking up hay the low in the 4 speed is nice put it in gear and let her crawl along while throwing bales just turn her at the end if the field LOL

Kenneth
 

kleedus

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Ray
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1960 threw 91
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c10 to k30
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350 threw 454
your 88 crew cab should have a 205 t case with the round pattern that should bolt up to a nv4500

i did the swap in my 85 i used a 94 nv4500 bellhousing and master and slave cylinders with a little modification they worked.

i put a 208 t case behind the nv4500 but i plan to put it in my 90 crew cab with the 90 round pattern 205
 

swagger

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Steve
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K20
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350/SM-465/NP-205
As far as the "lower gear"... Now isn't that the earlier older NV4500? IIRC, the early ratios were changed because of the large wide gap between 2nd and 3rd, the gears you'd be using as 1st and 2nd actually. So if you're not using that granny low very often or have a specific purpose for that deep low gear, you'd actually get better normal driving performance out of the later NV4500 instead of the early NV4500. Seems to me the 94 and older were the early ones, the 95 and later were the ones with the better gear ratios, but the granny low wasn't as low.

Good to know
I'm looking for one myself
 

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