K20 454/SM465 going into K5, all parts bolt up?

[urbex]

I'm sure this has been covered hundreds of times, and I'm just not thinking of the right search terms to use. I keep finding threads on the merits of the K10/20/30 vs a K5....

I have a '86 K5 with a 350/700R4 and the engine needs to be replaced. I picked up a '85 K20 that already had a 454 swapped in, with a SM465 hydraulic clutch/NP208 behind it. At this point I haven't yet decided if I want to keep the auto trans set up in the K5, or switch it to a manual (I know there are issues with getting a 700R4 to survive behind a big block, but I don't really want to give up overdrive, or deal with the issues with putting in a 4L80E, or cough up what it takes to buy a NV4500 and deal with the 5th gear issues in those, lol)

If I were to toss the 465 in the K5, would it essentially be a bolt in deal using whatever parts I needed off the K20?

 

[obijuank5]

Yes, you're on the right track. It is all basically a swap over. You should be able to even use your k5 driveshafts as they are now.
Clutch pedals swap in without much fuss. Shifter hole in the floor is already dimpled there just cut it open.
Swap the radiator and shroud too. Dont forget that.

Overall it's a direct exchange.

 

[urbex]

You should be able to even use your k5 driveshafts as they are now.
<SNIP>
Swap the radiator and shroud too. Dont forget that.

Driveshafts too? I haven't put a tape measure on the two, but I thought the 700R4 trans alone was something like 30 inches long, whereas the 465 and t-case adapter is something like 20 inches long?

I have a fairly new all aluminum radiator and electric fans in the K5 now, though it's a two row, that I was considering using with the BBC as well, though the big factory radiator in the K20 still appears to be in pretty good shape. At least good enough to send to a radiator shop for cleaning if need be, anyways. I never drove the K20 long enough to determine the true shape of the cooling system. Seems like I always have a fan clutch go belly up at the worst possible time, but have never had both electric fans die on the same trip, lol.

The more I think about it, the more I'm leaning towards just putting the 465 in the K5. While I'm not wild about pushing a clutch off road, I don't plan on making this a daily driver, so MPGs aren't really a concern to me, and I do like the lower chance of an issue popping up in the trans in the middle of nowhere stranding me 50 miles away from the nearest cell phone tower...and I figure worst case scenario, since this also won't be a hard core wheeler, I could get away with running taller axle gears to keep freeway RPMs down, and just using low gear more often to get rolling.

 

[obijuank5]

Standard trans offroad is badass. I love it.

In 1985 gm started kind of standardizing the lengths. Theres a good chance that front to back those two combos are the same.

 

[urbex]

Standard trans in the rocks is a PITA...it would be FAR from my first manual off road. My Samurai has one now, and it's the current wheeler (SPOA, 31s, 6.5:1 low range, bumpers, winch, and pre-crunched body panels...it's geared low enough that I don't have to work the clutch much off road, but it's miserable on the freeway.) If I didn't have to carve out the trans tunnel so much to fit an auto in there, I'd have never ran with the 5 speed.

 

[HankScorpio]

I have both a K5 and V3500 with sm465 and 4.10 gears with 37" tires. Goes down the highway just fine for me.

 

[imiceman44]

Standard trans offroad is badass. I love it.

In 1985 gm started kind of standardizing the lengths. Theres a good chance that front to back those two combos are the same.

They actually are same length.
That's why the adapter is so long.
The output shaft on the 465 is like 8-9" long

 

[urbex]

Ooooh...I just realized that the length of the 465 likely isn't including the bellhousing, whereas it likely is on the 700R4, so I can see the lengths being similar now.

It's not that I think the truck won't do freeway with the 465 in there, but rather that I'd be listening to the motor screaming at 3000RPM at 70MPH, whereas I'm at 2000RPM now. I know the motors will handle it just fine, I just don't want to be listening to it for an hour or two, lol.

I'd have to go a 2.73 gear with the 465 to get back to similar RPMs that the 700R4 gives me with the 4.10 gears, which I don't think I can even get for a 14 bolt (I'm running 10 bolts now, but I'm not wild about the thought of a big block, manual trans, and 10 bolts, lol). Highest that I can recall is something like a 3.23? Though a 3.23 only bumps me up somewhere around 250RPM, so it's not horrible, and I do still get a much better crawl ratio in 1st gear than I get out of the 700R4, though I'm not sure how much converter slip will compensate for that.

Then there's that whole issue with the 465 shifting like a dump truck trans, with shift throws feeling like I'm tossing the stick into the next county....(I ran a 465 in a Scout for a very short period of time...)

 

[HankScorpio]

Sounds like you should stay with an auto. The 465 is a dump truck transmission.

 

[Earldub21]

I picked up a NV4500 from car-part.com rebuilt for $1400 with warranty. Also the sm465 which I took out of my 89 suburban 2500 has an external slave cylinder, so long tube headers may be troublesome. Grimmjeeper.com has a gear ratio calculator you can put your tire size, gear ratio, trans and transfer case and give you your RPMs at a certain speed.