LE9 305 w ESC Performance upgrades '86 k5 Blazer

[1979 K10]

Hi all,
I just picked up a new to me 1986 K5 blazer. Glovebox build sheet says it has the LE9 5.0 Liter V8 Gas GM. It supposedly has 190k on it and runs really well except for some blue smoke unitl it warms up. I have the 700R4 4 speed auto and thankfully GT4 rear axle 3.73 and NP 208 transfer case.

1981-1986 LE9 with 4 Barrel Carb
Max Brake Horsepower: 165@ 4000 rpm
Max Torque: 250 @ 2000 rpm
Stroke: 3.48
Bore: 3.736
Compression: 9.5
Firing Order: 18436572

Truck runs good and looks like it has the 4bbl quadrajet. Everything is stock, air pump, vacuum lines everywhere, stock exhaust. Catalatic converter was removed at some point.

I live at 7k ft elevation and could really tell the performance drop when driving it home from 5k ft elevation.

1. Will dual 2.25 exhaust help or is that too much exhaust for the 305? Thinking about just putting dual 2.25 and leaving the stock manifolds. https://www.summitracing.com/parts/wlk-89005

1a. Long tube Headers + dual exhaust? https://www.summitracing.com/parts/sum-g9006

2. The LE9 has Electronic Spark Control, any upgrades for that to make the timing advance come in earlier? Can I just set total timing at 32 degrees like a normal HEI with vaccum advance unhooked and ESC left alone?

3. I have the big factory air cleaner with factory cold air intake. Leave that alone or switch to the "hot rod" standard open element that takes in air from the engine bay? Warmer air but no restriction from the stock setup.

4. I can tune an edlebrock carb but haven't messed with the quadrajet. Its probably running rich but I may try putting smaller primary jets in it. If I do the exhaust that should lean it out a little, correct?

5. We don't have emissions testing where I live, I was going to unhook the air pump and delete a bunch of the vacuum lines related to emissions. Do I need to plug the air lines into the manifolds or just leave them as is with no air pump?
5a. There is a vacuum operated valve on the exhaust down pipe, guessing that is for faster cold start warmup.

Thanks for the help!

 

[1979 K10]

I deleted the 90’s steps, and going through and changing all the fluids.

 

[1STLS1]

At 190k and blue smoke until its warms up, it may be near the end of it's normal service life. You may be able to throw valve guide seals at it and cure some of the oil consumption but may have other issues.

First step is run a compression test and a leak down test to determine what condition the engine is in. Also pull the distributor cap and turn the engine one way then the other while watching the rotor to figure out how much slack is in the timing chain.

These are things I would look at before trying to add headers and such.

 

[Ricko1966]

I would advise against messing with esc. and egr, if they are working properly. At least drive it as long enough to see how it runs now vs. after you disable them. 305s are pretty preignition prone,those items help. Biggest bang for the buck performance was is swap in a different engine. This is not B.S. . If you're just after a functional truck that gets decent mpg. Leave your 305 and basically stock, good tune,headers, single exhaust or h/y pipe,as for your qjet being too rich,unless it's just idle mixture,you'll probably need adjust apt and change primary mains.

 

[1STLS1]

I would advise against messing with esc. and egr, if they are working properly. At least drive it as long enough to see how it runs now vs. after you disable them. 305s are pretty preignition prone,those items help. Biggest bang for the buck performance was is swap in a different engine. This is not B.S. . If you're just after a functional truck that gets decent mpg. Leave your 305 and basically stock, good tune,headers, single exhaust or h/y pipe,as for your qjet being too rich,unless it's just idle mixture,you'll probably need adjust apt and change primary mains.

These are good points but I will also add oil consumption causes pre ignition/ detonation so your ESC system could be pulling back the timing even more.

 

[1979 K10]

Spark plug recommendations? I’ve had good experiences with NGK G power (small platinum tip) and NGK V power (larger non platinum tip)

They offer a two heat ranges:
UR4 colder plug
UR5 hotter plug

I was thinking the hotter plug due to high mileage. Coolant temp runs 180 - 200.

 

[Ricko1966]

Run a stock plug unless you are having a problem. Hotter plug more chances of preignition or setting off esc. Colder plug more likely to foul.

 

[Grit dog]

^What he said. General consensus is don’t fck with a functioning ESC motor.
Exhaust, fine. New valve guides, fine. Tune carb, fine. If everything else is working, leave it be.
Look for posts by @SirRobyn0
He has a fully functional 305 daily driver and goes into great detail about the 305 ESC etc. and he’s a professional mechanic, so super knowledgeable and capable.
My only reference and didn’t understand until @SirRobyn0 explained is dad had an 85 c10 305 back in the day and “got rid of all that electrical nonsense” when it was giving problems.
Never ran 100% right after that. Literally everything explained here now made sense 30 years later.

 

[1979 K10]

The spark plugs in it look good so just going to leave those alone.

 

[TotalyHucked]

Agreed with everything above. You won't gain much out of a 305 period, let alone if the ESC is working correctly. I'd leave it alone until you have a problem. Then drop in a 383/LS/big block/whatever flavor and do away with the ESC completely

 

[1979 K10]

I put a blueprint 400 sbc in my 79 k10. Also converted from 600cfm edelbrock carb to Holley Sniper 2 EFI. Wow what a difference from the tired old original 400.

Stock 400
185HP
300TQ

Blueprint 400
500HP
500TQ

GM Small Block Compatible 400 c.i. Engine - 500 Horsepower - Long Block

BluePrint Engines 400 c.i. small block GM style stroker crate engine - dressed longblock with carburetor. Includes 30 month / 50,000 warranty & BPE Dyno Promise. Part #: BP4002CT1

blueprintengines.com

I ordered it during COVID 2021 and it was $1300 cheaper than the price today.

The ol turbo 350 trans is still holding in there... I added a Hughs performace 2400 stall torque converter and left the rest of the trans as is.

 

[SirRobyn0]

^What he said. General consensus is don’t fck with a functioning ESC motor.
Exhaust, fine. New valve guides, fine. Tune carb, fine. If everything else is working, leave it be.
Look for posts by @SirRobyn0
He has a fully functional 305 daily driver and goes into great detail about the 305 ESC etc. and he’s a professional mechanic, so super knowledgeable and capable.
My only reference and didn’t understand until @SirRobyn0 explained is dad had an 85 c10 305 back in the day and “got rid of all that electrical nonsense” when it was giving problems.
Never ran 100% right after that. Literally everything explained here now made sense 30 years later.

I've said it before and I'll say it again. I "think" that the people who remove their ESC and feel the truck runs better must have had an ESC system that was performing terribly before removing. Because a properly functioning ESC is what's best or at least it was for me. I got my truck with a bypassed ESC and then spent a lot of time and effort getting it working again. The biggest problem is that the ESC module is hard to get, so much so that having you existing unit rebuilt is probably the way to go. @Grit dog is right I have a thread about my ESC journey you'll just need to search ESC and my user name to find it. With that said I have read none of this thread other than the quote so hopefully this is helpful.

 

[Grit dog]

I've said it before and I'll say it again. I "think" that the people who remove their ESC and feel the truck runs better must have had an ESC system that was performing terribly before removing. Because a properly functioning ESC is what's best or at least it was for me. I got my truck with a bypassed ESC and then spent a lot of time and effort getting it working again. The biggest problem is that the ESC module is hard to get, so much so that having you existing unit rebuilt is probably the way to go. @Grit dog is right I have a thread about my ESC journey you'll just need to search ESC and my user name to find it. With that said I have read none of this thread other than the quote so hopefully this is helpful.

He’s back! The man the myth the legend!
Happy New years Rob! Hope it treats you well!

 

[SirRobyn0]

He’s back! The man the myth the legend!
Happy New years Rob! Hope it treats you well!

Thanks buddy happy new years to as well! Maybe 2025 be better for all of us!