Another way to skin the cat; the High Torque 292 LS swap

[dayj1]

I picked up a solid '72 SWB stepside back in February. I finished up the bulk of my LS swap a few weeks back, but I took lots of pics along the way and thought I'd post the details of the swap.

Here's the only "before" picture that I have.



The driver's fender and door were repainted at some point in the past, but the rest of the truck sports the original paint and it's all original sheet metal. The bed wood also appears to be original, but someone had replaced the 307 and manual tranny with a 350/350 combo.

I've had this taking up room in my shop for the last year or so waiting on the right vehicle to come along for a swap:



It's the "littlest" LS; a 4.8. Since 4.8L converts to 292.9 cubic inches, I decided to round down and call this a 292 swap

The 4.8 came from a 79K mile 2003 Tahoe. I bought it over a year ago and slowly gathered parts. It's got a mish-mash of truck and Camaro parts for the accessory drive and a LS1 'vette intake.

Every good LS swap starts with lowering the truck, right? 3 inch spindles in the front and 4 inch springs in the back left us with this:



Then, I snatched out the 350.

[dayj1]

The first order of business was the mounts. I've done several swaps, but this is the first time that I had a SBC and a Gen 3 motor sitting side by side. So, armed with my trusty tape measure I came up with adapter plates for the stock towers and mounts to place the motor just where I wanted it. I made these mounts out of 3/8 plate. There pretty much run of the mill plates, except that the SBC mount holes are 1/4" below the Gen 3 mounting holes. This will raise the motor by about 1/4".

Here are the plates in the middle of painting:



I also needed to modify the passenger's side tower. First, I removed the top of the tower:



Then a duplicate of the mount "top" in flat steel:



Welded together and a rough pass with the flap wheel:



Gusseted under the edges to add back some strength and blasted:



All done, in paint:

[dayj1]

It was around this point in the swap that I decided that I wanted the new engine to have an old look; Chevy orange and all. I was going to need coil relocation brackets. There are several choices out there for car coils. Truck coils, not so much. I decided that I wanted them behind the heads. So, the fabrication started.

The brackets started as simple angles to bolt to the back of the heads. I center drilled some spacers out of 3/4 rod on the lathe:



With coils attached:



Painted and fully assembled. Notice that they aren't exactly the same since there is just a little less room behind the driver's cylinder head:

[dayj1]

After a coat of Chevy orange, the engine went in:





Those are Gen 5 Camaro exhaust manifolds. Here's some shots of the clearance to explain why I made the plates to raise the motor by 1/4" and why I removed the "hump" from the top of the passenger's side tower:

[dayj1]

I ordered some LS/SBC valve cover adapters on eBay and some plain Jane orange sheet metal valve covers. I also had to throw the intake on there just to see how it looked.



I liked the look of the LS1 intake. But, it wasn't quite what I wanted and things really went off the rails.

Friends with water jets are cool. Especially when you need things like a square bore to 3-bolt TB adapter:



I ordered up a Holley intake and attached the adapter:



And a test fit of the TB. That's the #1 shop dog, Vance, in the background, BTW.



Here is is sitting on the engine:

[dayj1]

I took a break from the engine for a little while to work on my radiator.

I took the stock 4 core radiator to a local shop and, $50 later, it got a clean bill of health. I had the heater hose outlet on the tank brazed shut while it was there.

After a little tin-bending:



And some paint:



For a lower hose, I used the piece on the left:



The upper hose was cut at the the tape:



The upper hose also needed a reducer on the water pump end:



Istalled:



And, since I despise worm clamps, some spring clamps:

[dec010974]

I am dying to see/read the rest of this post. im interested to see the wiring and tuning for this application. I had a dream I completed a swap, just like this, using the same combination of parts such as intake and throttle body. I assume your going with a speed density tune? good luck. Clark. don't forget to spill all the beans. knowledge is power.

[lt155ruck]

Would this be considered in the "stock" location or inch back etc?

Originally Posted by dayj1

The first order of business was the mounts. I've done several swaps, but this is the first time that I had a SBC and a Gen 3 motor sitting side by side. So, armed with my trusty tape measure I came up with adapter plates for the stock towers and mounts to place the motor just where I wanted it. I made these mounts out of 3/8 plate. There pretty much run of the mill plates, except that the SBC mount holes are 1/4" below the Gen 3 mounting holes. This will raise the motor by about 1/4".

Here are the plates in the middle of painting:



I also needed to modify the passenger's side tower. First, I removed the top of the tower:



Then a duplicate of the mount "top" in flat steel:



Welded together and a rough pass with the flap wheel:



Gusseted under the edges to add back some strength and blasted:



All done, in paint:

[dayj1]

Originally Posted by lt155ruck

Would this be considered in the "stock" location or inch back etc?

Using the bell housing mounting surface as the point of reference, the plates that I made move the "LS" engine 1 inch forward of the SBC.

[lt155ruck]

Thanks for that, I'm not sure why that seems to confuse me... must be getting older.

[Beetle]

So putting the throttle body on an intake like that works? That gives me ideas I shouldn't be having with my soon-to-be LS swap. You also have me motivated to go 4.8 instead of 5.3L. I bet the cost difference is enough to justify it. I won't be racing my truck, just want a cruiser at this point and something better than my 250/Powerglide setup. By the way you need to find some 292 fender badges

[dayj1]

Originally Posted by Beetle

So putting the throttle body on an intake like that works? That gives me ideas I shouldn't be having with my soon-to-be LS swap. You also have me motivated to go 4.8 instead of 5.3L. I bet the cost difference is enough to justify it. I won't be racing my truck, just want a cruiser at this point and something better than my 250/Powerglide setup. By the way you need to find some 292 fender badges

Yep, it works great. It drives just like the 4.8 in my 2012 daily driver. As for the cost difference, I gave $500 for the motor. The cheapest 5.3s around here are $1000. It wasn't cheap to change the look of the motor, though. Going through my receipts, it was about 1K for parts that you wouldn't normally need.

And, I beat you to it on the badges, I bought a pair from board member mahanian back in March.

[GMC-YA68]

Extremely impressive build. I love how you gave it the old school look.

[jessemthompson]

Great build!!!

[dec010974]

dayj1, nice. im very much impressed. I have a few idols in the LSx world. My Top 3 are. This list is in no particular order.
LS1Nova71
MeanyellowZ
dayl1.

[Hart_Rod]

Dang Jonathan, you've been busy! The truck looks great and as usual, awesome attention to detail! Post more pics!

[Willie Makeit]

the boy is an artist (pronounced: r-teest)

[ls1nova71]

Wow, Jonathan, this looks awesome! I assume this is what you need the cruise lever for? I haven't forgotten about it, just been really busy but will get it done, I promise. Couple of questions though, first, is the pump really loud in the tank in the cab? I had a buddy who put a pump in the stock opening and it worked, but he hated the noise. Second, how did you get the speedometer to work with the original face? I assume it's pretty close to accurate, but the odometer is off?

[mattcrp1]

Quick question for the spedo swap guys, will that s10 set up work with a '76 type dash/cluster?

[mongocanfly]

Nice way to "skin that cat"
Beetle..on the steam ports my engine guy said I didn't need them so I cut off all the tubing and welded up the banjo ends and bolted em back to the heads.if you look at his post #11 in the last pic you can see the tube going across the front of the intake and into the water pump.my 6.0 didn't plumb into the pump it went to the radiator and not having a fitting there I chose to block it off.

[mooseknuckles]

very cool! you do great work.

[Marty68]

awesome.you need to look at it a while to see what it really is.

[Houston Ben]

All I can say is...WOW!!! Would you come to Texas and rebuild mine?? lol!

[whitels1]

Great Job! I dig the old school valve covers and the air filter/housing set up.

[dayj1]

Originally Posted by dec010974

dayj1, what are the part numbers for the holley intake and fuel rails? I have the holley LSx dual plane intake.

300-137 for the intake and 534-219 for the rails.

Originally Posted by Houston Ben

All I can say is...WOW!!! Would you come to Texas and rebuild mine?? lol!

Originally Posted by whitels1

Great Job! I dig the old school valve covers and the air filter/housing set up.

Thanks!