LS3/6L80e Engine Swap into my 73

[WPS 73 Bronco]

I feel like I've crossed a major milestone on this build. From the Radiator to the Transfer case, everything is installed. It been a big clime to get to this point, but it feels like it's downhill from here. When I did a similar project 10 years ago on my 72 corvette, it took 2 years. I think I'm only 2-4 months away from driving this one, which would end up taking 12-14 months. I plan to dedicate some time during the Xmas holidays to focus on it. My punch list is getting shorter. Below are the big items:

- Finish coil to spark plug wiring
- Transmission and TC shifter cable install
- Install Transmission oil cooler
- Button up final wiring (5 to 7 different connections to be completed)
- Exhaust system - I bought the Duff SS Dual exhaust kit. I know it will need to be modified.
- Rear diff 3rd member and axle swap followed by driveshaft installation.
- Brake bleeding
- Fluid fill and first crank . I could actually do this now with just a little bit of work.

 

[1969miller]

what are your plans for spark plug wires? The headers i have for my 6.0 are tight, way too tight for the stock plug boots.

 

[73azbronco]

finger width is pretty much EB standard clearance, so that all looks great, well done.

 

[WPS 73 Bronco]

what are your plans for spark plug wires? The headers i have for my 6.0 are tight, way too tight for the stock plug boots.

The wires were part of my coil pack relocation kit. I haven’t looked at this yet. Hope there’s not a problem. What headers do you have? Mine are Sanderson.

 

[WPS 73 Bronco]

Back at it this week. I’m off all week so I hope to make a lot of progress.

Today I changed the transmission cable bracket as I wasn’t happy. It barely cleared the front drive shaft so I made a new bracket. It actually shifts better.

After that I changed spark plugs and torqued down my headers. Here’s a pic of the plugs that were removed. They all look the same except cylinder 7. It’s clean while the others have normal carbon etching. No oil anywhere. Ant thoughts about cylinder 7?

 

[WPS 73 Bronco]

Here’s underneath driver then passenger.

 

[Yeller]

I wouldn’t think much of it.

 

[WPS 73 Bronco]

New problem…… Oil pan clearance with the front diff-pumpkin.

I have the Holley 302-02 pan. Below is a pic of the dimensions.

The sump area of the pan has only about 1” clearance on the corner of it, with the front diff-pumpkin. When you compress the suspension the pan corner and the dif bottom out together. Holley has a different pan that has a shorter length rear sump, 7.78”. This might work, but I’m not sure.

How much pan clearance do you need before compressing the suspension?

 

[WPS 73 Bronco]

Here’s the comparison between what I have (3302-02) vs the other option.

 

[Yeller]

the stock height one that I did, I had to go to a steel pan and trim the corner of the pan and trim a web on the housing for everything to clear, its really tight.

Unfortunately I'm terrible about taking pics anyway and of things that tend to be frowned on I take even less.

Edit:
PS- aluminum can be trimmed and rewelded as well.

 

[WPS 73 Bronco]

Couple updates:

I ordered a steel oil pan from Speedway. It should arrive on Thursday and I will install it, and determine the modifications needed. I will have it at a fab shop on Monday and back in my hands within a couple days.

Started the exhaust install today. I had purchased the Duff 2.5” SS dual exhaust, knowing that I’d have to have an exhaust shop make the final connections from the header back to the Duff system. When I opened the box from Duff that’s been on my shelf for about 6 months, I found only one Magnaflow muffler. I’ll be calling them tomorrow to get the 2nd one shipped to me.

My plan was to start at the rear of the exhaust and work towards the motor. Using the hangers they provided along with coat hangers, I was able to mock the passenger side up. Of course I ran into issues. The main problem is the pipe routing around the M1A1 23 gallon gas tank. The Duff design looks like it a perfect fit, except the mounting bracket/all-thread bold on the tank rock guard is clearly in the way. I’m guessing I‘m going to need to modify the M1A1 mounting bracket. It was a pain in the a$$ when I installed it, and I thought it was a terrible design.

I’d really like to see some pics underneath of anyone that has dual exhaust and the large Tank in the rear. I’d also like to see additional pics of the entire exhaust run from Transfer case to the exhaust tips. I’d also like a side view of a Bronco so I can see the exact location the where the exhaust pipe exit lines up on the truck. I’ve started another thread with this issue so I’d get a wider audience and responses.

Thanks

 

[WPS 73 Bronco]

Another question….

Do you prefer to hang your mufflers horizontal or vertical. The Duff kit is designed to go vertical. Since I’m modifying the kit, I can go either way. I think Horizontal looks better and fits nicely. Not sure about heat though. I have heat and sound shield in the interior, and could always wrap the muffler if needed.

 

[Yeller]

I’ve done both, vertical usually is quieter inside.

 

[EPB72]

Another question….

Do you prefer to hang your mufflers horizontal or vertical. The Duff kit is designed to go vertical. Since I’m modifying the kit, I can go either way. I think Horizontal looks better and fits nicely. Not sure about heat though. I have heat and sound shield in the interior, and could always wrap the muffler if needed.

I can post pics tonight im doing the same thing right now.. 2into 1 bit 2.25 tail pipe dealing with same bracket j bolt area ,,, muffler is vertical with 35 degree tilt but is a quiet flow so little different..

 

[DirtDonk]

Yep, what they said. Either way works fine.
It’s all about fitment. If one way works better under yours, that’s the best way. If they’re both about the same, then you choose.
I can’t say for the vertical being quieter, but it would actually make sense. I’ve done both, but never with the same type of muffler twice.
So no direct apples to apples comparison.

 

[WPS 73 Bronco]

Progress this week.

- Installed passenger side exhaust, except to header. Waiting on replacement muffler from Duffs to complete drivers.
- Installed Trans cooler, need to complete fluid lines (AN hoses). Fan shroud to be completed this week with dual 6” fans and installed this weekend.
- Identified cast aluminum oil pan doesn’t clear front diff. Ordered new steel pan and marked up for modifications needed. Should be ready to install this weekend.
- Identified M1A1 gas tank bracket was in the path of the dual exhaust. Pulled tank and have redesigned hangers ready to be fab’d this week. Install this weekend.


Here‘s a pic of the trans cooler without the fans.

 

[nvrstuk]

Making great progress.

Mounting mufflers vertically also means less potential surface area radiating heat into the floor boards.

Where is the cooler being mounted?

Might hold off on connecting the exhaust to the headers unless you are 100% sure you won't have to move the frt diff an inch or whatever to avoid the frt diff. Hope your oil pump or pickup or whatever might be in the way allows you to cut the pan and weld it since modifying the pan is ton easier than moving the diff fwd an inch.

Like Steve said, wouldn't worry about that plug being a little cleaner than the others.

 

[WPS 73 Bronco]

The trans cooler is mounted under the radiator between the frame rails. It will pull air from the engine bay. If the temps aren't where I want them, I will reverse the fan to a push and bring cool air the engine bay. TBD.

Regarding the oil pan, I'm removing a significant amount off the corner of the new pan for clearance. It won't affect the pickup, which is what I was hoping for.

I'm getting close. I might try and fire it up this coming weekend.

 

[Yeller]

The pickup won’t be an issue, you can cut a 3rd if the sump off before that gets in the way. Those pans hold 7 quarts so a significant amount can be cut off before getting below the 5 quart minimum needed to safely run the engine.

 

[WPS 73 Bronco]

Any guess as to what gauge steel is in the pan? I'm guessing 12 or 16 gauge? I have a sheet of 16 gauge, but I'm thinking that might be too thin.