5.3 LS Engine Swap into Ol’ Blue 1971 Chevy Truck Part 5


Part 5!! We mount V-band clamps on factory truck LS manifolds and fabricate the exhaust.

Step 1. Hack off the factory collector flanges.

Ol' Blue 5.3 LS Swap

Step 2. Match up the new 2.5″ V-band flanges described in part 4

I cut the flange off with a 7" grinder as close as I could to the flange.

I cut the flange off with a 7″ grinder as close as I could to the flange.

Step 3. Preheated the manifolds and collectors. The Wife loves it when I put truck parts in the oven…

Ol' Blue 5.3 LS Swap

 

Step 4. Weld on the V – Band flanges. I welded both the inside and the outside.

Ol' Blue 5.3 LS Swap Ol' Blue 5.3 LS Swap

 

Step 5. I put them back in the oven, turned it off, and let them cool slowly. (no pics, not exciting)

Step 6. Clean up the welds, and paint.

Ol' Blue 5.3 LS Swap Ol' Blue 5.3 LS Swap

Ol' Blue 5.3 LS Swap Ol' Blue 5.3 LS Swap

Step 7. Reinstall with new hardware. The Dorman 03413B Exhaust Manifold Hardware Kit worked great.

Ol' Blue 5.3 LS Swap

Ol' Blue 5.3 LS Swap

Ol' Blue 5.3 LS Swap

That wraps up the Manifolds. Next, we need to set up the exhaust.

The v-band fittings have a male and a female part to them. I welded the male ends onto the manifolts. To start running the exhaust, I put the female ends . A light tap with a rubber mallet sets them right in.

The v-band fittings have a male and a female part to them. I welded the male ends onto the manifolds. To start running the exhaust, I put the female ends . A light tap with a rubber mallet sets them right in.

My 2.5" exhaust kit from Summit Racing. The cheapest kit I was able to find.

My 2.5″ exhaust kit from Summit Racing. The cheapest kit I was able to find.

Take the kit, pick an appropriate angle. Then cut it off and tack it to the v-band fitting. Continue building from the manifolds back.

Take the kit, pick an appropriate angle piece of tube. Then cut it off and tack it to the v-band fitting. Continue building from the manifolds back.

In full disclosure, I was planning on making a Y pipe and using a single Flowmaster 70 that I had bought used off Craigslist. What actually ended up happening was that I decided the Y pipe was too much work, so I ended up re-using the dual exhaust that I took off the truck. The Y-pipe was turning out to be very difficult having to work around the front driveshaft and torque converter cover.

The old Exhaust....

The old Exhaust….

The old exhaust was 3" tubing and my new exhaust is 2.5". Therefore I need to adapt the smaller tubing to the larger exhaust opening. Eight slices with the grinder, a little hammering, and the tubes fit right up.

The old exhaust was 3″ tubing and my new exhaust is 2.5″. Therefore I need to adapt the smaller tubing to the larger exhaust opening. Eight slices with the grinder, a little hammering, and the tubes fit right up.

Bad picture looking up from underneath the truck. The black dot is where I will be putting the O2 sensor bung.

Bad picture looking up from underneath the truck. The black dot is where I will be putting the O2 sensor bung.

Got it tacked up good and pulled it all out so I could fully weld everything.

Got it tacked up good and pulled it all out so I could fully weld everything.

Adapting the mufflers turned out to be no big deal. Looks just fine. It is not a show truck and I don't have or see the need to spend more money than necessary.

Adapting the mufflers turned out to be no big deal. Looks just fine.

Bosch 13026 O2 sensor for '01 Yukon and weld in bung from Vibrant Performance VIB11105

Bosch 13026 O2 sensor for ’01 Yukon and weld in bung from Vibrant Performance VIB11105

Bosch 13026 Oxygen Sensor
Vibrant 11105 Oxygen Sensor Weld Bung

Bosch 13026 view of the plug on the O2 sensor and my wiring harness.

Bosch 13026 view of the plug on the O2 sensor and my wiring harness.

I drilled the hole for the O2 sensor with a step bit. Drill a step at a time until you get the right size.

I drilled the hole for the O2 sensor with a step bit. Drill a step at a time until you get the right size.

Step Drill Bits are a MUST for any shop. They are so handy, and can be had for CHEAP at Harbor Freight or Amazon: Step Drill Set – 3 Piece

I made the hole slightly bigger than the inside threads of the bung.

I made the hole slightly bigger than the inside threads of the bung.

O2 Sensor installed

O2 Sensor installed

Finish welded and painted.

Finish welded and painted.

That pretty much ties up part 5. Check out Part 6 for the first start!! I just need to finish odds and ends like belts, coolant, fuel, and wiring.

 

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