LS Swap in a stock-height '72 4x4?

[joeydurango]

I'm planning to do a 5.3 LS swap in my 1972 K10. The truck isn't lifted or lowered, just the stock height. I've heard some folks claim you can't LS swap into a stock-height 4x4 because of clearance issues between the oil pan and differential. The guys at Pacific Fabrication - who seem super-knowledgeable and friendly, by the way - say the swap will work fine with their 4x4 crossmember and their low-height LS oil pan. I trust their experience, but wondered if anyone here had done what I'm about to do, just to confirm it can work. Anyone out there with the same, or similar, conversion? Thanks!

[Bigdav160]

I have no direct experience but I have not read of any engine oil pan interference with the swap. Make sure to read the LS conversion topic.

There are reported clearance issues with the front driveshaft and transmission oil pan at stock height.(4L60e)

How's the snow in Durango? Our family has been skiing there 20 years straight.

[joeydurango]

I've been reading through the LSx swap topics, and have definitely seen some people claim of engine oil pan/front differential clearance issue on stock height trucks. But that's that PacFab says will be taken care of with the low-height oil pan.

Now, this is the first I've heard of 4L60e/driveshaft clearance issues. That's a bummer, as we're going that route as well. Do you have any details on that or info on where those reported issues are listed? We're keeping the oldie-but-goodie NP205 t-case, which I assume is probably what most people do...

The snow down here in town is next to nil. Up at the mountain, though, I hear it's been pretty good... and the backcountry skiing is awesome right now.

[DWilbur]

I'm doing a LS 5.3 in my 71 K20 I picked up a cross member from Dirty Dingo. the stock cross member is not wide enough to fit the LS block. My truck has a 6" lift.

[joeydurango]

Yep, using the Pacific Fab 4x4 crossmember to take care of that!

[K10 STEPSIDE]

I am part way threw my lm7 swap. and the stock oil pan has about 2.5 in of clearance between it and the axle. I took out my old cross-member and made my own mounts. to me it looks like you have to raise the engine, put in a 1.5 or 2 in lift., or limit the suspension. The cross-member and oil pan from pacific fab would be tight but should work.

[joeydurango]

PacFab told me that if the stock suspension is in good shape, it *should* all work together. They recommended a 2" lift, though, just to make sure. I really don't want to lift the truck, so we're proceeding without, and we'll find out how it works soon. Just waiting for the engine/tranny package to ship, and getting ready to take the truck to the frame shop for a few minor repairs before the swap.

I'll keep this updated with progress.

[ryanroo]

Hey, a durangotang!

i have no experience in swapping that engine into this truck, but i do know there are a lot of OEM pan configurations that can possibly help you out. i did some research to that when i was building buggies at avalanche, but dont really remember the whos and whats.

where about the durango area are you? i am over in Baytucky.

[joeydurango]

Hey Ryan, yep, another guy hiding out in the middle of nowhere we call SW Colorado - perfect! I'm in-town DGO.

We do have a low-profile aftermarket pan that will be used on our LS engine. Fingers crossed it all works out without major issues. Now if only UPS would get on it and deliver our ORD steering box brace so that we can get down to the frame shop in Farmington...

Skimmed through your LONG build thread. Holy crap man - that truck is going to be an amazing monster. You're quite the fabricator, that's awesome!

Hey, do you have an extra jack and accessories from your parts truck you want to sell? Our truck didn't even come with a spare, so will be looking for the jack and so on once this rig is ready for actual road time.

[ryanroo]

Id have to go look through the pile of stuff in my garage. my parts truck turned into my daily driver a few months ago. i didnt have the heart to cut it up and i happened to sell my other DD. so, if you see the ugliest yellow truck in the world, its probably me.

thanks for the compliment. i work as a fabricator, so i have a some advantage over others in that department. let me know if you ever need a hand with yours, and you are welcome to come out to the garage anytime. i mostly just stand around and make loud noises for my neighbors, but once in a while i actually get some work done

[joeydurango]

Just an update on this - finally have most everything together and we tried putting everything in today. Keeping the t-case in the stock location, with an Advance Adaptors part for the 4L60e, and using a 2002 LS 5.3, the Pacific Fab crossmember doesn't have enough clearance to the differential. Oil pan to diff should be fine, but the crossmember itself will bottom out on the diff with any decent suspension compression. Can't really move the engine back any further - not much room up against the firewall. User FirebirdJones somehow did the same swap in a stock-height truck with no issues, but maybe he replaced the springs or something - after 42 years, you'd think there would be some sag in the original leaves. Working on a solution, will post up with results.

[K10 STEPSIDE]

I took some pictures under my truck last night and thought I would come back to show my clearance. It would be posible if the bump stops were lowered for safety and the pan changed for one with more clearance.
This is my stock height truck with 5.3 and custom mounts. (I am planning on lifting the truck before I put it back on the road.)


These are my engine mounts now, I am unsure if frame twist will be an issue. I am going to try it like this and add a cross member if i need it.


Just out of curiosity what oil pans would help with clearance. I would prefer not to lift.

[joeydurango]

I think Pacific Fabrication made the low-profile oil pan that came on our 5.3. They also made the crossmember we used.

Looks like to me that with the low-pro pan, you may be able to get away with it with no crossmember, assuming your springs are in good (great?) shape. But I'm not clear on how well the non-crossmember setup works, I've heard varying opinions.

I didn't want to limit the suspension (lowering bump stops), and wanted to keep the crossmember - so we ended up lifting the truck by 2".

[DWilbur]

It looks your motor mount bolts or welds to the out side of the frame and drops down under lowering the engine. The Dirty Dingo mount I have fits in-between the frame rails and raps around the oil pan. I think my motor sits higher than yours. I do have a 6" lift.