Planning a 700R4 to SM465 swap

[brendo613]

Hey all,

I'm hoping to get some info from GM gurus, at whatever price I have to pay (I'm prepared to be very laughed at). I have an '88 5.7 TBI Vandura 2500 with a 700R4 acting up, and I don't want to play games - well, not with fixing an automatic at least Don't want to spend more than $300 on a trans, so I gotta plan out a swap to an SM465.

I found GM code GU6 in the glovebox: assuming I have a 3.42 rear with a 700R4 (and 220/75/15 tires), the van cruises @ 65mph @ 1848rpm. I played with this handy gear ratio calculator until I got a setup that looks usable. With a SM465 and a 2.41 rear (and 220/75/15 tires), 65mph comes at 1861 rpm. The rest of the gear range looks usable for getting up to highway speed as well, heh. Unsynchronized 1st will be fun, too (planning on using L as 1st).

So - I need help with the flywheel and clutch release mechanism part. I don't mind cutting and welding to get a pedal assembly into place, but I do mind spending a lot of money - so Novak's hydraulic release kit is out of the question. Does anyone know if a C / K series pickup clutch pedal assembly will fit in the van? Also, I've heard that in 86 the rear main seal design changed - so I'll need a flywheel from an '86 or newer, correct? Driveshaft lengths are going to get creative, too. (Just trying to sort major hurdles beforehand.)

D'oh. This isn't an easy one ... but man would it be cool

 

[Jims86]

Hey all,

I'm hoping to get some info from GM gurus, at whatever price I have to pay (I'm prepared to be very laughed at). I have an '88 5.7 TBI Vandura 2500 with a 700R4 acting up, and I don't want to play games - well, not with fixing an automatic at least Don't want to spend more than $300 on a trans, so I gotta plan out a swap to an SM465.

I found GM code GU6 in the glovebox: assuming I have a 3.42 rear with a 700R4 (and 220/75/15 tires), the van cruises @ 65mph @ 1848rpm. I played with this handy gear ratio calculator until I got a setup that looks usable. With a SM465 and a 2.41 rear (and 220/75/15 tires), 65mph comes at 1861 rpm. The rest of the gear range looks usable for getting up to highway speed as well, heh. Unsynchronized 1st will be fun, too (planning on using L as 1st).

So - I need help with the flywheel and clutch release mechanism part. I don't mind cutting and welding to get a pedal assembly into place, but I do mind spending a lot of money - so Novak's hydraulic release kit is out of the question. Does anyone know if a C / K series pickup clutch pedal assembly will fit in the van? Also, I've heard that in 86 the rear main seal design changed - so I'll need a flywheel from an '86 or newer, correct? Driveshaft lengths are going to get creative, too. (Just trying to sort major hurdles beforehand.)

D'oh. This isn't an easy one ... but man would it be cool

Ummmm....have you planned out how you are going to shift it?

 

[RetroC10Sport]

Well, the G van was never available with the SM465, but it WAS available with the MY6 New Process A833 OD 4 speed also used in trucks. So the clutch linkages are out there. You would have to fab up some sore of shifter because with the truck shifter you'd be shifting from the back seat area...Or just have someone sit back there and shift it for you...

 

[brendo613]

I'll keep some passengers handy, hahaha

With the inner hood off the van, the top of the bellhousing is to the right of the driver's seat; reckon a toploader SM465 would place the shifter inbetween the front seats

 

[brendo613]

Yo that MY6 A833 sounds pretty cool ... helluva a lot easier if I got my hands on one of those. Thanks for pointing that out - I wasn't able to find out what manual trans the vans came with

 

[RetroC10Sport]

I've got a 1979-84 G van illustrations manual scanned, I'll post the clutch linkage illustrations.

 

[bucket]

If you're main goal is cost, your best bet is just sticking another auto in it. 700R4, 2004R, th350, th400... whatever you find cheapest that you can test drive before it's pulled. I like the 4 speed idea though, I hope you can find all the rare van parts to make it work. That would make for a very fun van

 

[smurph20]

Not sure if itll work but look for the Astros thats were stick. A lot fo work vans out there that are stick so you might be able to adapt it too work in your fullsize van.

 

[brendo613]

Wow! Yeah that manual would be awesome to have a look at, Jay.

Fortunately and unfortunately, planning this swap is definitely an endeavor in "fun" - since I was a little kid I always wanted a big, stickshift van. Eh, we all have our dreams

 

[RetroC10Sport]

Here's the clutch linkage and parts list.

Here's the A833 shifter setup.

 

[brendo613]

Wow man, if only I could grab the parts right off that page Finding that linkage would be so hard I bet. I know of a truck junkyard about 10 miles north of me where I got a few things for my '86 F150 and a new grill for the Van (took it from a Suburban), but I might be lookin for a long time for a stick van :|

Looks like the clutch and brake pedals share a bracket like the pickups do

 

[RetroC10Sport]

I actually have a friend that has a 1984 A833 G van...She drives that thing all over hell's half acre.

 

[brendo613]

Next time you see her you can tell her how a junkyard boy with a creepy van outside Philly is jealous of her

 

[bucket]

Hmm, Astro parts are a good suggestion. Couple the pedals and hydro linkage (assuming they are hydro) with the fairly sturdy but common NV3500 5 speed from a '91 and newer S10.

 

[RetroC10Sport]

I'll watch in the yards here...They seem to get in some of the strangest optioned vehicles...