'86 Jimmy 4in Lift, 40’s, tons, 8.1 Swap- 700r4 said PNNNNN

[6872xtc]

@GWeakland620 this is a small detail, but if you flip the 4 jumpered power wires 180* as an assembly, then the splitter butt connector will be able to drop down some. Should be a little cleaner with that little loop dropped downward.

Nice work!

 

[GWeakland620]

Neither of us have hydro assist on the steering. If you have the ps and ac bracket is that uses the normal Saginaw pump all you'll have to do is swap the aero belt pulley over to your pump and bolt it into the bracket. So your existing setup won't have to change. You just need the right pulley.

So tonight I was going to swap my pumps out. Well after pulling the 8.1 pump, I found out my SB350 pump does not line up with the holes in the 8.1 bracket. Any ideas?

 

[campfire]

So tonight I was going to swap my pumps out. Well after pulling the 8.1 pump, I found out my SB350 pump does not line up with the holes in the 8.1 bracket. Any ideas?

Can you modify the bracket?

Post some pictures of the geometries involved.

 

[GWeakland620]

Can you modify the bracket?

Post some pictures of the geometries involved.

It’s a cast bracket.

 

[GWeakland620]

So I found that my pump does have the holes, but the neck at the top is hitting the bracket before I can get the holes lined up.





Is there a way to rotate the pump inside the reservoir?

 

[campfire]

So I found that my pump does have the holes, but the neck at the top is hitting the bracket before I can get the holes lined up.

View attachment 334220

View attachment 334221

Is there a way to rotate the pump inside the reservoir?

I think so, but I got around that problem by using an external reservoir. Is that an option for you? If not, @Blue85's engine shows a workable combination. But that looks like a different bracket.

 

[GWeakland620]

I think so, but I got around that problem by using an external reservoir. Is that an option for you? If not, @Blue85's engine shows a workable combination. But that looks like a different bracket.

That’s the factory 8.1 pump.

 

[Blue85]

The pumps are all the same, but the reservoirs are clocked in different directions for different apps. For example, see my pictures in the hydroboost thread. https://ck5.com/forums/threads/illustrated-hydroboost-swap.306221/#post-3266103

FYI, I bought that pump used off eBay and it was pretty cheap (the one that came on the engine was damaged). If you can't find a stock application clocked correctly, you could just cap off one of the return lines on an 8.1 reservoir. Almost looks like a stock TPI reservoir would work in your application, though.

 

[GWeakland620]

I think that’s my next route. Find a pump that is clocked enough to work, and still use my hydro lines that are already made.

After looking at the pump, there’s no way you can clock this one.

 

[ZooMad75]

You could rotate the housing on the pump but I'd bet it leaks. But I've never had a reservoir off a pump and put it back on without it leaking. Might be just me though. LS power steering pumps do have the same offset to the reservoir than the 8.1 pump does.

 

[GWeakland620]

You could rotate the housing on the pump but I'd bet it leaks. But I've never had a reservoir off a pump and put it back on without it leaking. Might be just me though. LS power steering pumps do have the same offset to the reservoir than the 8.1 pump does.

How do you rotate the housing? Looks pretty specific with the bolt on the back.

 

[ZooMad75]

How do you rotate the housing? Looks pretty specific with the bolt on the back.

Well shit you got me on that one. I guess I've only had the reservoirs off to swap them, not rotate. My brain is fried with work stuff lately.

 

[obijuank5]

Yeah just change the can. Tons of different shapes.

 

[GWeakland620]

Found this unit. Looks like it has the same shape as the factory 8.1 hydroboost unit, but doesn't have the extra return line. And it should work with my lines that are already made. Vehicle application is a '92 Silverado TBI.

 

[GWeakland620]

Part number is 20-8704 for reference.

 

[GWeakland620]

Lines are hooked up and pulley is on. Everything worked perfectly. On to the next stage!

 

[GWeakland620]

Final serpentine I stall with fan and shroud. Just need a lower radiator hose and the engine is done. Still have a couple grounds to attach, then run some power wires. After that it’s down to O2 sensors and computer mounting. Getting closer.

 

[ZooMad75]

Awesome!!! We need video of the first fire. Keep at it!

 

[GWeakland620]

I can’t find a lower radiator hose that works.
Factory small block was too small.

Factory 7.4 liter was too small on one end and moulded wrong.

Factory 8.1 has a T in it.

 

[ZooMad75]

I can’t find a lower radiator hose that works.
Factory small block was too small.

Factory 7.4 liter was too small on one end and moulded wrong.

Factory 8.1 has a T in it.

If you are using the medium duty/Workhorse brackets the standard BBC lower hose is the ticket. I'm not sure what the GMT800 bracket using people are putting in since the hose comes out in a different position. Larry has a post on it below.

8.1 Swap info