87’ Engine Retrofit 86’ Truck Issues?

[aotte1]

Have a 1986 chevy Silverado short bed 4WD loaded truck, 700R4, needs engine ( gone). Opportunity to buy 1987 tbi 350 out of suburban, again loaded engine including AC. The 87’ engine includes all accessories. Will 87’ accessories, e.g. AC bolt up to 86 truck accessories connections. 86’ truck has original engine bay wire harnesses, are they compatible to 87’ accessories? 87’ engine has 115K miles.
Understand need to change intake to carb, along with distributor/MSD. Will 87’ 350 block allow use of mechanical fuel pump?

As alternative have 88’ Blazer with worn out 350 engine can use for engine bay parts, choosing alternative long block.

Thanks,

[aotte1]

Photos of 86truck. Sorry for photos being upside down- that is what Apply software does.

[kipps]

I've heard it both ways. Some folks say they've found a cam lobe inside the fuel pump hole, and the mechanical fuel pump worked fine. Others say they've tried this, and there's no lobe on the cam in this spot. There's also the chance that the block doesn't have a opening for the fuel pump at all. A quick visual examination should prove this, though.

The other thing to be aware of-- the intake manifold bolts changed angles when the TBI engines were introduced. A carb intake won't bolt directly to TBI heads, unless you slot out the bolt holes with a grinder. Many folks have installed carbureted intakes on these engines, so the research has been done. It's easy enough, but is not as bolt-on as you might think it should be.

Another option-- Is the complete TBI harness and computer available with that engine? If it's in VERY good shape, it might be best to just swap the whole thing over. Remember that GM "piggy-backed" the TBI system onto the squarebody trucks. It's hardly an integrated system. I would only attempt this if you have access to the entire parts truck, though. You'll need things like the ALDL connector, ECM tray, fuel lines, etc.

[57NAPCO]

Don’t know if I’d go to all that trouble to install an engine with 115,000 miles, especially if you don’t know the history the engine.
Just my thoughts...

[b454rat]

Dont know bout the fuel pump, but 86 started the canted center bolts, so should be able to unbolt TBI intake and bolt a carbed one on.

[kipps]

Originally Posted by b454rat

Dont know bout the fuel pump, but 86 started the canted center bolts, so should be able to unbolt TBI intake and bolt a carbed one on.

Had not heard that. Thanks. But even so, he'd need to find a 1986 carbed intake to get it to bolt-on. That would be a one year only intake, which could be a needle in a haystack to find.

Here's a complete intake and carb kit from summit that's designed for the TBI cylinder heads.

https://www.summitracing.com/parts/cmb-03-0199

[Corts60]

The '87 and later engines have the Vortec intake bolt pattern, which has 8 bolts and they are drilled at an angle to the intake mounting surface. I have a factory '86 burb with the original engine in it and it is the old school '55-'86 intake pattern of 12 bolts and they are perpendicular to the intake mounting surface.

There are numerous vortec bolt pattern intakes that are made for carb swaps out there. Look at jegs or summit.

[b454rat]

Originally Posted by Corts60

The '87 and later engines have the Vortec intake bolt pattern, which has 8 bolts and they are drilled at an angle to the intake mounting surface. I have a factory '86 burb with the original engine in it and it is the old school '55-'86 intake pattern of 12 bolts and they are perpendicular to the intake mounting surface.

There are numerous vortec bolt pattern intakes that are made for carb swaps out there. Look at jegs or summit.

This is incorrect. The Vortec pattern is 4 bolts per side, 2 front, 2 rear. They came out in 96. In 86 when they went to center bolt pattern, the 2 inner most bolts were on an angle, that went to the Vortecs, 95 last year. you can take a regular intake and elongate those bolt holes. It's easy to do. S-10s called their V-6 Vortec, but has nothing to do with the later ones.

[aotte1]

Thanks, kipps, 57NAPCO, b454rat, Corts60, for your comments, all great information. Still deciding how to go, considering. Will update my thinking as it develops.

[kipps]

This might be going down a rabbit hole that's not desired, but at least give a passing thought to a LS engine.

Gregski has a good thread in this 73-87 forum titled "restoring rusty." In the last couple pages, he details a beginner's approach to installing and tuning an LS on a family man's budget.

[b454rat]

I just bought a 6.0 today, and been looking at a **** ton of vids, builds, whatever trying to learn more bout em. I'd love to have a square again, it would be stupid easy to install in one. Once the harness is thinned out, only need 3-4 wires to hook up. I bought it to put in my Tahoe, even then the wiring isn't horrible. Haven't started yet, but should be doable. Check out Richard Holdener on YouTube, granted perfect world, but makes some nice numbers with stock junkyard motors.

[KrazyRay]

86 and 87 pulleys should be the same with part of them running a v belt and part with a serpentine belt. The AC should also be the same mounted on the driver side. Most early tbi engines will accept a mechanical fuel pump. Your 87 donor engine will have a block off plate at the fuel pump. Remove that and install the mechanical pump. If you can, use the original clam shells from the truck as there can be different bolt spacings for the cross bolt. I have no problem putting a 115k tbi engine in a truck. Most of them are good for 300k in not tortured by the previous owner.

[kipps]

aotte1, also if it helps anything, I've got a scrap takeout 1987 TBI 350 sitting around here somewhere. If you come up missing any accessories, brackets, etc, let me know, and I'll look around my collection.

[Just call me Sean]

I thought I would add what I know from what I've had. '86 is the first year of the one piece rear main seal block, which I had in my '86 K5. But, it had the old style heads with perimeter bolt valve covers so the intake isn't a one year only thing. My '87 had center bolt valve covers and TBI. The '87 had a fuel pump block off plate.

[THI]

Originally Posted by Just call me Sean

I thought I would add what I know from what I've had. '86 is the first year of the one piece rear main seal block, which I had in my '86 K5. But, it had the old style heads with perimeter bolt valve covers so the intake isn't a one year only thing. My '87 had center bolt valve covers and TBI. The '87 had a fuel pump block off plate.

This is correct, you would need an aftermarket intake for a carb on an '87-'95 engine or modify the original to work with the canted bolts. My 1986 K20 had a 350 with a 1-piece rear seal, but still had the old style heads. If you look up aftermarket heads, they are listed for 1986 and earlier or 1987-1995.

[aotte1]

GMPP 350 HO 330 is the motor using, it is used with 20K miles, runs great. Getting from original owner, out of 1969 chevelle, 3.08, single track, older gentleman in his 80’s. Friend has maintained engine whole life, has written history. Note; water pump short set-up is not correct.

[aotte1]

Will paint it back 86’ engine color.
Question is which engine accessory with AC set-up to use. Options considering 86 (serpentine, V-belt combo), 87 ( serpentine) or new GMPP kit. GMPP kit has AC on left side?

[Just call me Sean]

Those look like Vortec heads. Did you get an intake with it?

[aotte1]

Will paint it back 86’ engine color.
Question is which engine accessory with AC set-up to use. Options considering 86 (serpentine, V-belt combo), 87 ( serpentine) or new GMPP kit. GMPP kit has AC on left side?

[kipps]

Originally Posted by aotte1

Will paint it back 86’ engine color.
Question is which engine accessory with AC set-up to use. Options considering 86 (serpentine, V-belt combo), 87 ( serpentine) or new GMPP kit. GMPP kit has AC on left side?

My 1987 had a v-belt & serpentine combo. If I remember correctly, the serpentine belt drove the alternator, and the v-belt went to the power steering pump. Both belts went around the crankshaft and waterpump pulleys. There was no AC or smog pump on my engine. There were no tensioner or idler pulleys. the alternator and steering pump were both pulled tight and bolted firmly.

I don't know how original my TBI engine was, though. Things could have been swapped around by previous owners.

[aotte1]

Sean and Kipps,
Sean, Original owner keep air-gap Edelbrock for his new engine. Replacing it with Edelbrock for Vortec heads 2716 performer EPS. Will post photo, selected for driver, low rpm torque, with 700R4. Likely no high rpm sprints in future.

Kipps, how do you like the 87’ set-up, vs full serpentine belt? The photos below are of our 86’ step side with maybe similar belt/pulley set-up as your 87?
The new to us 86’ short bed K10 will have AC.

[kipps]

Originally Posted by aotte1

Kipps, how do you like the 87’ set-up, vs full serpentine belt? The photos below are of our 86’ step side with maybe similar belt/pulley set-up as your 87?
The new to us 86’ short bed K10 will have AC.

It had all the typical v-belt problems. Trying to shim the power steering pump to improve belt alignment, using crowbars to pull the pump tight before bolting it down, etc.

I'm not going to regret this full serpentine setup on my LS one bit. The cast-aluminum accessory brackets will eliminate any problem with misalignments.

If you have any way of getting hold of an affordable full-serpentine setup, don't hesitate!

[Just call me Sean]

I would pull the brackets from an early '90s truck or van. My '93 truck has the short a/c compressor (same yours would have but with a serpentine pulley) on the passenger side, my '92 van has the next generation compressor on the drivers side. I have seen either on both, and passenger cars have other options. Brackets from passenger cars are more likely to have a place for a smog pump.