Found a lead on a used engine, couple questions

RecklessWOT · Oct 24, 2020

I got a call today from a friend that knows I need an engine for my 'Burb. He says he knows a guy selling a running TBI 350 for $200, I think he said it's in a '98 chevy pickup (can't remember which year he said but it was late 90s). I'm already sold because that's a great price for any running 350 around here.

But as far as I've heard, regardless of price I think that's a better engine than my '87 anyway, right? In those later years what differences can I expect to find? Did they have vortec heads by then? Will it be plug and play or will I need a new computer? Which sensors and such can I expect to be different? I'm assuming it has a serp belt, can I just throw my pulleys on it or is it not so simple?

1987 GMC Jimmy · Oct 24, 2020

Huh? So they converted a post-‘95 vehicle and engine to TBI, the year stated here is wrong, the friend is mistaken (confusing TBI and CSFI/MPFI), or it’s A TBI long or short block with Vortec-era engine management stuff.

Assuming it’s just a newer “Vortec 5700,” the improvements are a serpentine accessory drive, much better heads (assuming they’re not cracked, valve seals/guides shot and also the springs have a lift duration ceiling of .450 so if you want a cam that gives you more, you need upgraded springs), the cam is a better spec’d roller rather than hydraulic flat tappet, and the mechanical fuel pump provisions are general gone where it would be hit or miss on ‘87-‘95. With a Vortec TBI intake, you could probably run this engine without modding anything using your current engine management setup. Now if you wanted to use the OBDII stuff, you’d have to have the PCM, harness, sensors, etc.

If it’s a ’93-‘95 and actually TBI, the differences include, but are not limited to, a two post air cleaner, a different TPS pigtail, and you don’t have the external ESC module unless it’s a manual transmission truck. Autos incorporated the ESC circuit into the PCM for like model year 1993, but I can’t remember if it’s in the MEMCAL or if it’s just an integrated thing. The newer air cleaner should work with the older snorkel, but don’t quote me on that.

Oh, you’d need new refrigerant lines for the compressor being in a different position, and then you’d probably have to add some wire so your alternator can reach the factory wiring. Their positions are swapped on serpentine drives.

RecklessWOT · Oct 24, 2020

1987 GMC Jimmy said:
Huh? So they converted a post-‘95 vehicle and engine to TBI, the year stated here is wrong, the friend is mistaken (confusing TBI and CSFI/MPFI), or it’s A TBI long or short block with Vortec-era engine management stuff.

Assuming it’s just a newer “Vortec 5700,” the improvements are a serpentine accessory drive, much better heads (assuming they’re not cracked, valve seals/guides shot and also the springs have a lift duration ceiling of .450 so if you want a cam that gives you more, you need upgraded springs), the cam is a better spec’d roller rather than hydraulic flat tappet, and the mechanical fuel pump provisions are general gone where it would be hit or miss on ‘87-‘95. With a Vortec TBI intake, you could probably run this engine without modding anything using your current engine management setup. Now if you wanted to use the OBDII stuff, you’d have to have the PCM, harness, sensors, etc.

If it’s a ’93-‘95 and actually TBI, the differences include, but are not limited to, a two post air cleaner, a different TPS pigtail, and you don’t have the external ESC module unless it’s a manual transmission truck. Autos incorporated the ESC circuit into the PCM for like model year 1993, but I can’t remember if it’s in the MEMCAL or if it’s just an integrated thing. The newer air cleaner should work with the older snorkel, but don’t quote me on that.

Oh, you’d need new refrigerant lines for the compressor being in a different position, and then you’d probably have to add some wire so your alternator can reach the factory wiring. Their positions are swapped on serpentine drives.

Thanks for the info. I'm gonna go see it myself in person on Monday after work (the guy is selling me a 4 post lift and just so happens to have this truck sitting around that the engine is in, gotta go there anyway to measure the lift to make sure it fits in my garage) so I can get to the bottom of it and see what year the truck is and which fuel injection actually has. There is a good chance my friend is mistaken on the year, he's quite old and not in the greatest shape these days so he mixes stuff up a lot. Hell, for all I know it's an '89 and he mixed the numbers up. But I have met the guy who's selling the engine a couple of times in the past so he does know what truck I drive and he runs his own shop mainly working on older american stuff (he personally has a few Mopars and a Nova and IIRC I think an older square too so I'd assume he wouldn't tell my friend the engine would work in my truck if it was wrong, but who knows)

Hah, I have no desire to taint my vehicle with OBD2 so I would be sticking with my factory wiring, worst case scenario if it is too new I'd just use the long block and heads and swap out the intake for a vortec TBI. I don't mind running some extra wire for the alternator if need be and my A/C doesn't work much anyway so I probably wouldn't even bother hooking it back up. But are the mounting holes in completely different spots or are we just talking different brackets as in would I be able to mount up my accessories in their original place? Honestly I couldn't care less about the serpentine drive, I'm not against it if it is convenient to use I'll keep it but if I can keep my factory hoses/wiring by simply converting it back to v-belt I'd rather just do that. I remember the engine that was in my '87 longbed was from a '93 or '94 Tahoe and while I don't specifically remember exactly where the accessories were mounted I remember it still ran v-belts so I'm guessing it's not too hard to swap over.

HotRodPC · Oct 24, 2020

RecklessWOT said:
I got a call today from a friend that knows I need an engine for my 'Burb. He says he knows a guy selling a running TBI 350 for $200, I think he said it's in a '98 chevy pickup (can't remember which year he said but it was late 90s). I'm already sold because that's a great price for any running 350 around here.

But as far as I've heard, regardless of price I think that's a better engine than my '87 anyway, right? In those later years what differences can I expect to find? Did they have vortec heads by then? Will it be plug and play or will I need a new computer? Which sensors and such can I expect to be different? I'm assuming it has a serp belt, can I just throw my pulleys on it or is it not so simple?

Yep, that's SFI (Sequential Fuel Injection) Vortec engine. JUMP ON IT if that's what it is. Roller motor and Vortec heads !!!

HotRodPC · Oct 24, 2020

RecklessWOT said:
Thanks for the info. I'm gonna go see it myself in person on Monday after work (the guy is selling me a 4 post lift and just so happens to have this truck sitting around that the engine is in, gotta go there anyway to measure the lift to make sure it fits in my garage) so I can get to the bottom of it and see what year the truck is and which fuel injection actually has. There is a good chance my friend is mistaken on the year, he's quite old and not in the greatest shape these days so he mixes stuff up a lot. Hell, for all I know it's an '89 and he mixed the numbers up. But I have met the guy who's selling the engine a couple of times in the past so he does know what truck I drive and he runs his own shop mainly working on older american stuff (he personally has a few Mopars and a Nova and IIRC I think an older square too so I'd assume he wouldn't tell my friend the engine would work in my truck if it was wrong, but who knows)

Hah, I have no desire to taint my vehicle with OBD2 so I would be sticking with my factory wiring, worst case scenario if it is too new I'd just use the long block and heads and swap out the intake for a vortec TBI. I don't mind running some extra wire for the alternator if need be and my A/C doesn't work much anyway so I probably wouldn't even bother hooking it back up. But are the mounting holes in completely different spots or are we just talking different brackets as in would I be able to mount up my accessories in their original place? Honestly I couldn't care less about the serpentine drive, I'm not against it if it is convenient to use I'll keep it but if I can keep my factory hoses/wiring by simply converting it back to v-belt I'd rather just do that. I remember the engine that was in my '87 longbed was from a '93 or '94 Tahoe and while I don't specifically remember exactly where the accessories were mounted I remember it still ran v-belts so I'm guessing it's not too hard to swap over.

I like that plan if there is such a thing. I don't know cuz I never checked into, but if you can get a TBI intake for Vortec heads, I'd do it too. You might even be able to get a big block Throttle Body with bigger injectors in it to take advantage of the higher compression and Vortec heads.

I get it, I wouldn't want to add a bunch of wiring, ECM swap and all that mess to go to the spider assembly SFI system. But, I wouldn't be considering going OBD2 as tainting my vehicle. OBD2 is much more standarized and a bit smarter than OBD1 that TBI uses. If you think your truck is worthy of the time and effort, not a thing wrong with stepping up to OBD2 from OBD1.

RecklessWOT · Oct 24, 2020

HotRodPC said:
I like that plan if there is such a thing. I don't know cuz I never checked into, but if you can get a TBI intake for Vortec heads, I'd do it too. You might even be able to get a big block Throttle Body with bigger injectors in it to take advantage of the higher compression and Vortec heads.

I get it, I wouldn't want to add a bunch of wiring, ECM swap and all that mess to go to the spider assembly SFI system. But, I wouldn't be considering going OBD2 as tainting my vehicle. OBD2 is much more standarized and a bit smarter than OBD1 that TBI uses. If you think your truck is worthy of the time and effort, not a thing wrong with stepping up to OBD2 from OBD1.

I'm aware that the SFI is a much better system than TBI and OBD2 is a much more advanced system, I just don't like the hassle of keeping an OBD2 system happy. It feels like if you fart in the wrong direction on the wrong day of the week you set off some check engine light. And they try too hard to compensate for stuff, they seem a little more resistant to mods than a dumb old OBD. You're right they are more intelligent, but that's a large part of what I don't like about it. Also I am very bad at most things electrical beyond simple stuff like toggle switches and stereos, OBD2 has wayyy too much electrical crap going on for me to comprehend. I like to keep it simple. I have newer vehicles in the driveway, but that's what I love so much about my square is that it's simple simple simple, and I'd really like to keep it that way.

If I did use a big block TBI would I need to switch to the big block ECU as well, or is it so dumb and easy to fool that it'll still just squirt as much as it thinks it should but now it's actually through a larger nozzle so more fuel will come out? I need a new brain box anyway, I've been running one from a 305 for the last 5 years or so. I swapped it in a pinch because my factory unit quit and this one worked good enough, then kind of forgot to getr around to getting the correct one back in there hah

bucket · Oct 24, 2020

You can use a 454 tbi, but use 350 injectors. The IAC valve is a different style, but you can change out the pigtail or buy an adapter. The linkage also does not have a stud for the 700r4's TV cable, so that needs dealt with too.

1987 GMC Jimmy · Oct 24, 2020

To answer HRPC, Edelbrock and GMPP have Vortec TBI intakes. They’re expensive, though.

To answer OP, yeah your accessory holes are all the same. Personally, I’ve always liked v belts more, and the more I deal with serpentine, the more I like the v belts. It’s nice to not every accessory tied together, and you’re only talking three belts as opposed to one or two. And then they came up with timing belt/chain driven accessories, which that’s totally for the birds.

TBI is simpler than SFI and arguably more reliable without that stupid spider. It’s pretty common to convert to a Gen III style MPFI system in those. Can’t argue with that, it’s a more bulletproof system IMO. I wouldn’t switch to OBDII either so I don’t think it’d be a hellacious endeavor no matter what the engine is, Vortec or TBI.

bucket · Oct 24, 2020

Nearly any 4bbl manifold can be a tbi manifold with just a low-cost adapter.

HotRodPC · Oct 25, 2020

bucket said:
Nearly any 4bbl manifold can be a tbi manifold with just a low-cost adapter.

True that, but the Carbed Vortec intake isn't all that cheap either so I'd think by the time you added the adapter, may as well just do the TBI Vortec. Of course you'd have a better chance of finding a used Vortec Carb intake.

HotRodPC · Oct 25, 2020

RecklessWOT said:
I'm aware that the SFI is a much better system than TBI and OBD2 is a much more advanced system, I just don't like the hassle of keeping an OBD2 system happy. It feels like if you fart in the wrong direction on the wrong day of the week you set off some check engine light. And they try too hard to compensate for stuff, they seem a little more resistant to mods than a dumb old OBD. You're right they are more intelligent, but that's a large part of what I don't like about it. Also I am very bad at most things electrical beyond simple stuff like toggle switches and stereos, OBD2 has wayyy too much electrical crap going on for me to comprehend. I like to keep it simple. I have newer vehicles in the driveway, but that's what I love so much about my square is that it's simple simple simple, and I'd really like to keep it that way.

If I did use a big block TBI would I need to switch to the big block ECU as well, or is it so dumb and easy to fool that it'll still just squirt as much as it thinks it should but now it's actually through a larger nozzle so more fuel will come out? I need a new brain box anyway, I've been running one from a 305 for the last 5 years or so. I swapped it in a pinch because my factory unit quit and this one worked good enough, then kind of forgot to getr around to getting the correct one back in there hah

I see your points there. I had a different outlook totally. While you're 100% on target, I looked at OBD2 as easier for me because it is smarter the fault codes tend to do a better job at diagnosis. That's just how I looked at it and became more fluent with OBD2 than I ever got with OBD1 IMO. The other thing I liked about ODB2 was the fact that it was more universal between breeds. If you could work on OBD2 GM, then you could work on OBD2 Ford and Dodge too. Pros and Cons to both for sure but sometimes it's all about the mindset and I guess I'm lucky I seen it the way I did and it's what got me interested enough to tolerate it.

Now you want your friggin mind blown, play with some CANBus. OBD2 is a walk in the park compared to CANBus. The days of 1 computer on a vehicle are long long gone. Now you have 5-7 computers on a vehicle and they all talk to each other on the CANBus. (Computer Area Network Bus) Bus meaning the information highway where all the computers read each others sensors and share info. For example, Cruise Control is part of the body control module but it reads the VSS off the powertrain control module. The ABS system also reads the VSS and even the ARS reads the VSS so it knows not to set off air bags if the vehicle is going less than 35mph at the time crash and inertia sensors are tripped. I find it a bit intriguing myself so it doesn't scare me a bit.

Frankenchevy · Oct 25, 2020

HotRodPC said:
Now you have 5-7 computers on a vehicle

Or forty...

cant remember, but I recall a tech advisor telling me that when I took one of my newer trucks in.

HotRodPC · Oct 25, 2020

Frankenchevy said:
Or forty...

cant remember, but I recall a tech advisor telling me that when I took one of my newer trucks in.

If he calls a sensor a computer then maybe so. Most vehicles since 2008 or so have at least a Powertrain Module, Body Control Module, Traction Control Module, ABS Module, and ARS Module. Then sometimes, modules can be split. You may have a Body Control module for creature comforts and one of other body features, or Engine computer and a Transmission Computer that make up the powertrain control module. I think 40 computers is a stretch though.

hoagster · Oct 25, 2020

HotRodPC said:
I see your points there. I had a different outlook totally. While you're 100% on target, I looked at OBD2 as easier for me because it is smarter the fault codes tend to do a better job at diagnosis. That's just how I looked at it and became more fluent with OBD2 than I ever got with OBD1 IMO. The other thing I liked about ODB2 was the fact that it was more universal between breeds. If you could work on OBD2 GM, then you could work on OBD2 Ford and Dodge too. Pros and Cons to both for sure but sometimes it's all about the mindset and I guess I'm lucky I seen it the way I did and it's what got me interested enough to tolerate it.

Now you want your friggin mind blown, play with some CANBus. OBD2 is a walk in the park compared to CANBus. The days of 1 computer on a vehicle are long long gone. Now you have 5-7 computers on a vehicle and they all talk to each other on the CANBus. (Computer Area Network Bus) Bus meaning the information highway where all the computers read each others sensors and share info. For example, Cruise Control is part of the body control module but it reads the VSS off the powertrain control module. The ABS system also reads the VSS and even the ARS reads the VSS so it knows not to set off air bags if the vehicle is going less than 35mph at the time crash and inertia sensors are tripped. I find it a bit intriguing myself so it doesn't scare me a bit.

listen up guy's @HotRodPC, I have worked on CANBus machines and the software has to be perfect and the connections between each input/output have to be also for it to work right. It is getting better and a lot of the farm equipment and heavy equipment are using it.

HotRodPC · Oct 25, 2020

hoagster said:
listen up guy's @HotRodPC, I have worked on CANBus machines and the software has to be perfect and the connections between each input/output have to be also for it to work right. It is getting better and a lot of the farm equipment and heavy equipment are using it.

Yep, it has alot of room for failures as complicated as it is which means lots of room for improvement and it should only get better. Some don't care for it at all. It is a necessary evil though. You can have all these tree huggers talking about getting rid of oil and use alternative methods which they too have their major downfalls so no matter what source you use for transportation, heating, energy or whatever the case may be, there will always be harm to the environment or something that causes cancer. In the last 30 years we've come a very long way as far emissions output, and fuel efficiency. The improvements didn't come without the use of computers so get used to them. They're here to stay. I don't mind the research into other technology but this ******** of no oil usage is for the birds. AOC can swallow this !!! That's all.

Found a lead on a used engine, couple questions

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