1981 C10, 6.0 LQ4 swap with Manual Trans Exhaust Question

His all. I am swapping out my old 305 with a 6.0 LQ4. Truck has an New Process A833/MY6 4 speed manual in it, with a manual clutch linkage. I am using ICT Billet motor mount adapters to keep the sbc engine placement so everything should fall back where it was with the 305. Plan right now is to keep the manual clutch linkage (future, I will swap in a hydraulic but I need to recoup some cash first). Just looking things over it appears the stock cast manifolds will line up the exhaust below the clutch linkage. Do any of you know if this is the case or not and if I need to go ahead and get some aftermarket manifolds on order? If I need to order some, I'd appreciate some recomendations.

Dropped in the 6.0 this weekend



I also built some brackets to mount the stock LS fuse box on the fender. I am shooting for a "stock" look in the C10... as if you bought a C-10 in 2003.



Also got the heater core replaced (the duct was full of squirrel nests) and a drive by wire gas pedal installed.

This weekend I hope to get the radiator mounted (stock heavy duty LS radiator) and the coolant overflow tank mounted (you guessed it, the stock tank).

I have a drivers side battery tray on order. Once that comes in I plan to mount the ECU box to the support leg of the battery tray if I can figure out the bracket geometry.

Installed exhaust headers this weekend.

For those interested. Flowtech 11575FLT Shorty Headers with the clutch z-bar. The drivers side collector lines up almost dead center of the manual clutch linkage pivot bar. With a hydraulic clutch slave cylinder they would line up in a great location to work the exhaust pipes toward the back. Also plug #4 was really tight on my install with the Holly 302-1 oil pan with where the new dipstick is located. I would have had to go with ceramic plug boots for sure.

In other news the stock LQ4 cast iron exhaust manifolds drop the exhaust just right to miss the clutch linkage.

work

Ok so on the passenger side, using the stock manifolds. you can get flanges from summit. I used those. One ear on the passenger side you need to shave down to about half the thickness around the bolt hole or it will hit the frame. with 2-1/2" exhaust I was able to use one of the amazon kits and used the 45 degree bend, cutting off about 3" of pipe and canting it in the flange a little I get it right where it will go above the tans cross member and then its a straight run back to the rear axle. I added the O2 sensor on the top side of this pipe a couple inches past the bend and it fits right where it seems the stock wire harness wants it. It does look like I an going to need a 20 degree or so bend to kick the rear portion back in line with the frame. I need to measure that angle before I order a bend or one of those braided couplers.

The driver side.... in some ways was easier, in others tougher. The same 45 degree bend works great and lines up even closer than on the passenger side without cutting. The downside is I had to cant the pipe on the flange probably 3/4 to and inch. the hole in the flange was large enough i was able to tweak it in the flange to the angle i needed but had a good sized gap to weld up, and had to grind down a touch of pipe on the header side. Was able to place the O2 sensor like the other side, a couple inches after the bend on the top side of the pipe.... but the stock harness pigtail on this side is short so it was really a bear to clip the wire in. If the harness was 2" longer on that side it wouldn't have been hard at all. And the worst part, the cant you have to put on the pipe to get your alignment means the rear stud on the header is almost impossible to reach. You can turn approximately 1/4 turn at a time with an offset box end wrench. possibly you could use a crows foot on a ratchet, but a socket even with swivels is a no go, the pipe is so close to the stud there is no room for the deepwell socket. So be prepared for hand cramps and sore shoulders after that if your like me and working on the truck on jack stands.

Hope this helps someone contemplating a similar swap.

I'll try to remember to snap some pictures this weekend when I'm back under there. Just don't judge my welds, I'm not a welder!

Dang! I have the exact same stick welder and shop vac as you.

SquareRoot said:

Dang! I have the exact same stick welder and shop vac as you.

Click to expand...

Those are my brothers, we share a barn/shop.

I am not great at giving reviews but I wanted to drop a line here for LT1Swap.com. Brendan not only emailed me several times helping me diagnose an issue I was having with the ECU(PCM for some) but he actually answered the phone when I called. Extremely rare these days. I ended up sending him my ECU to get a tune for my build flashed onto it. He turned it around back to me faster than expected with the holiday AND most importantly the tune solved all the issues I was having. So I guess I'm saying, if you are doing a LS swap and need an ECU flashed and are in the same boat as me with few tuners around who know what they are doing, then maybe give him a shot.