Project "Yamahauler" 1989 K1500, 5 speed, LQ4

[SlowAndHighTBI]

My 1989 K1500 was in desperate need of some more power. It had a TBI 350 in it when I bought it. It never did quite run right. In fact, I took offense to how weak it was. It struggled badly trying to chug up the hills of eastern PA, loaded up with MX bikes, ATV's, gear and gas. Not to mention it got 10 mpg, at best, doing so.

I found a good deal on a complete 2004 LQ4 86k mi, with all accessories, ECM, harness, exhaust manifolds with flanges and various other odds and ends I ended up needing. I robbed them at the price of $800.

I started my swap off by removing the bed to access the fuel pump.

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Crusty looking, isn't it? After I got the fuel pump and sender swapped out, I decided that I should address the rusty frame. It received a few coats of KBS coating (POR-15 counterpart.)

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After I coated the rear section of the frame, I moved on to the harness. Here is a pic of the convoluted tubing stripped off and the harness ready for modification.

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A friend and I removed all of the unnecessary wires (as per lt1swap.com). With the wiring near completion on the donor end, I removed the 350 and started coating the front section of the frame.

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At this point the wiring was beginning to become a bit monotonous. This time I was tackling the truck end of the wiring.

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[SlowAndHighTBI]

While the LQ4 was on the stand I cleaned it up, and reset the valves. I also had to remove 3 broken exhaust manifold bolts, and helicoil 1 of them.

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I ended up picking up a set of really nice conversion motor mounts from ls1truck.com member beertestr. They worked perfectly. I ended up using an O'Reilly's Auto Parts flywheel for the swap mated up to an 11" SBC clutch. If you go this route, make sure you use 30mm length bolts to hold the pressure plate to the flywheel. The O'Reilly's flywheel is unnecessarily counter bored, leaving you with very little threaded material inside of the pressure plate mounting holes. I also used a different pilot bearing and throwout bearing.

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I had to enlarge the opening in the firewall to accept the express van throttle cable. I also had to bend my throttle pedal a bit so that the throttle body would close completely.

My fuel rail had both a return and a supply line. I used nylon quick disconnect repair lines to mate to my existing stock braided fuel lines.

I ended up using a NBS high pressure line and the OBS return line for the power steering setup.

I bought a pre-wired fuse block and relay center and integrated them into my modified LQ4 harness. I used all of the original k1500 sending units to control my gauges. I was pleasantly surprised when everything worked! The engine cranked for about half of a second and fired right up. It had a steady 50 lbs of oil pressure at idle. I had the truck towed to the exhaust shop where they welded up a connection between the old exhaust and the LQ4 flanges. Here's a few pics of it all buttoned up.

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I can't even begin to tell you how much of an upgrade this is over a TBI engine. I get 60% better fuel economy and it hauls everything I need it to without a problem. It has even destroyed a few hemi Rams.

[Mickeymotormount]

I know the feeling. I should have done the swap a long time ago.

Glad to see you got her up and running without much fanfare.

[beertestr]

Looking great. I did my first LS swap on a 93 Sierra that was the same color. That was 8 years ago, but I think I have a beer can on the crank damper pic somewhere too.. probably a Yuengling (aka Pennsylvania Pabst).

Did you use the LQ4 y-pipe as well? On both my 93 and 94 LS swaps I was able to use complete 99-07 exhausts. I kept mine stock sounding for stealth and DD-ability. I have enough noisy vehicles.

[jcrumpley]

Nice work. I see you left your battery in the stock location. Do you have any pics of the air filter and tube from the top? Did you build the that out of other parts?

I'm about the pull the 230,000 mile 4.3 from my 92 RCSB and install a 5.3 LM7. I'm keeping the five speed standard shift as well. I have everything I need except the flex lines and fuel rail adapters.

[SlowAndHighTBI]

Thanks guys.

Beertestr, I initially wanted to try to use a NBS exhaust. They yard where I was digging didn't have any in good shape. It's nice to know that they will work though. I'm planning on doing this again in a lowered 2wd obs.

Now that I think about it, I'm pretty sure we put away a few 12 packs of Yuenglings during the frame rehab. haha


jcrumpley, I don't have any pics from above. I'll try to get you one at some point, after I get back up to my cabin. I used a 90 degree 4" to 3.5" reducing coupler for the intake. The tubing is 3.5" with a 45 degree bend. I just cut it to fit. It's pretty close to the upper rad hose, but it works great.