Northern 91

[91Vieja]

Greetings. New member here, but I've been lurking around for a few years. Finally decided to post a thread for my truck. It's a 1991 Chevrolet K1500 4X4, Silverado, Extended Cab Short Bed, 5.7 TBI, 700r4 (presumably), F44 with a 14 bolt. I am the third owner.

The story: I bought this truck from my grandma in 2016 when my grandpa passed away, with 165,000 km on it. Original everything, including the windshield. He bought it in about 98 from the original owner, a guy who worked for my dad. I still remember going to pick it up for the first time with my grandpa when I was just a little kid, and I've got lots of memories of taking it camping & hunting growing up.

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This is what it looked like when I got it in 2016. It had been sitting for a year or so. A mouse had made a nest in the muffler, and there was a box full of cremated human remains under the back seat. Not sure to this day exactly who's they were or what grandpa was doing with them lol.

 

[91Vieja]

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So immediately I sold the canopy, and stripped off the old-man running boards.

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[91Vieja]

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The first owner had installed a CD changer under the front seat and an amp behind the rear bench. That, along with dumb trailer wiring was causing the battery to drain, so I pulled it all out. Also upgraded all the speakers at that time, and added a new alpine deck. Also took the opportunity to clean the remnants of dead-guy ashes out of the interior.

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The back window leaked from when my grandpa had locked his keys inside and broken in with a coat hangar, so I pulled a new one out of the auto wrecker along with some interior trim to replace a few worn things.

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About that time I also pulled out the stock exhaust & cat, and replaced it with a cheap summit 3" system. Did the ultimate TBI mods, added a K&N open element air cleaner, did a new distributor, plugs, and wires. For some reason I also replaced the rad hoses with blue ones. One day they'll go back to black. Basically that was it for a while.

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[91Vieja]

I got a new sierra, got married, and built a house, so the old truck got neglected for a while. I basically only took it for the odd Sunday drive. Then work situation changed, and I'm not commuting every day. So sold the sierra, and now the 91 is my daily. Consequently, it was time to start looking for more parts:

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Picked up a barely used set of steelies off of a 2010 silverado. My plan is to mount 33" Duratracs on these.

Then my wife found me a set of vortec heads in good shape:

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So I cleaned them up with my dremel, and painted them. Going to upgrade springs and retainers shortly to handle more lift before I install:

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[91Vieja]

Got sick of the frame rust, so I started the process of hitting the entire underside with the wire-wheel and re-painting:

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Before / After:

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Replaced the shocks and changed the diff fluid while I was at it:

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[91Vieja]

Cleaned up and painted the skid plates, and the rest of the frame:

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Also replaced the yellowed original headlights with cheap ones from rockauto.

 

[91Vieja]

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Payed another visit to the wrecking yard in preparation for the vortec head swap. Pulled the top end out of a '98 and scored the roller spider and lifter retainers. Was going to take the lifters too, but after seeing the sludge inside the motor I thought better of it.

So that's basically it up to this point. Plans for the near future are the vortec head swap. For now, I'm going to run it on the stock cam, and stock (modded) TBI, with the stock tune. There is alot of conflicting info about running vortecs on a stock tune, but TBI chips has mixed reviews to say the least, and going with a dynamic EFI setup and tuning myself is expensive, and in my opinion, still restrictive as you are limited to the 2 barrel TBI. For intake, the gm vortec tbi intake is way too expensive, so I'll likely go with just a regular carb intake with an adapter for the TBI. I'm hoping deleting the EGR and such won't mess with the computer too much.

While the heads are off, I plan on adding JBA shorty headers & y-pipe. While the y-pipe is out of the way, I'll pull the trans, and replace the leaky rear-main seal that intermittently drips on my garage floor. Probably dried out from sitting, truck still only has 175,000 km on it, and it's 28 years old. There is an occasional noise from the torque converter / front of trans that I can't identify under hard load. So a rebuild may be in order too, depending.

Down the road, the plan is to swap to a Roller cam, probably the HT383 cam, or maybe something a little bigger, but still want it to be a low rpm torque motor. At that point, I'll drop the fuel tank to upgrade the pump. Then, in an ideal world, yank out the TBI, and replace it with a Holley Sniper or FiTech self-tuning system. I like that Holley has hyperspark ignition which is plug and play for timing control. I'd consider doing an MPFI conversion like the Edelbrock proflo4, but the nice think about sticking to a throttle body / carb replacement system is that if I ever end up changing the motor to an LS or even a new small block, I can bolt the Holley Sniper right up to anything, while with the MPFI, the manifold would have to match the heads, so I'd be out of luck if it wasn't going on vortecs.

 

[PlayingWithTBI]

Welcome, enjoy your build. You may want to do some more research - your TBI intake manifold won't bolt up to your Vortec heads the center 2 bolts on each side are drilled ~72* instead of 90*. I'm using the Dynamic EFI EBL Flash-2 on my 88 5.7 TBI (bored out to 46mm 61#/HR injectors and "Ultimate Mods" with 18# spring (just ordered a 30# 7.4L spring and AFPR because my injectors are over 110% DC, WOT @ 5200RPM). This TB setup will support ~350HP/650CFM - enough CFM for a 5.7L @ 6000RPM

The EBL will run MPFI, 3 BAR boost, and wet NO2 also. It will Learn and Flash your tune, has 8 different "Banks" so you can have towing, performance, valet, emissions testing, etc. Takes 4 seconds to flash a tune.

Your 91 block will probably have the bosses for your roller cam spider but may not be drilled and tapped, no big deal.

Then, after you get it built the way you want it, your 700r4 will smoke. I just spent $2100 for a stage 2 (600HP) trans with 2300-2500 stall TC from TransDepot. It never ends but, I'm having fun!!!

 

[91Vieja]

Update. Picked up a GM Vortec TBI intake locally for under half-price. Brand new in the box. Guy ordered the wrong part number. Considering what these go for on Summit + shipping to Canada, i’m ecstatic.

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Anyone who has installed one of these please chime in with any tips you have. I’ve read that the brake booster vacuum line, and the cable bracket will need some massaging. Not a huge deal.

My bigger question is around EGR. Since I’ll be running headers, there won’t be a way to connect a tube from the exhaust to the port on the manifold. I don’t have to worry about passing any emissions inspection (the truck has no cat anyway). I’m planning on just plugging the port on the intake that the EGR tube would connect to, and installing the EGR valve and solenoid in place. My thought is that, if everything is plugged in, the computer won’t know anything is amiss, and I won’t get any CEL. Has anyone done something similar?

 

[skylark]

You still have a chance of a check engine light. The reason is that the o2 sensor won't be seeing the correlation between egr being dumped in the cylinders when the ecm is expecting to have the egr valve open.