Learn Me Vortec 5.0 - Rebuild, Replace or Retire

My current daily is a 1997 GMC Sierra with the 5.0 Vortec motor and 4L60E. Both have 150k+ miles on them. A combination of lifter noise, transmission noise and hard shifting remind me the combo has a finite life span. Also the motor is falling on its face around 4000rpm, maybe even more so than it once did. I did some standard maintenance lately (cap/rotor, plugs, wires, air filter), but the situation remains.

All of this has me thinking about a plan, both for the inevitable and for now. This truck is not and never will be a hot rod, but I need more power, especially on the top end. Being a Chevy small block, there are obviously lots of options from bolt-ons to crate motors. Right now I'm thinking about higher ratio lifters and/or cams, but know almost nothing about them or how the rest of the truck will react to either. I do know that I want to keep the truck relatively quiet and civil. Will lifters alone have a significant effect on performance? What cam might work best in an otherwise stock truck?

For the future, there are also a plethora of options for rebuilding both the motor and transmission. But at the point that they're both tired, does it make more sense to completely replace the drivetrain with something from a newer truck, particularly from a fuel mileage point of view? At the point that I'm replacing the drivetrain, does it make more sense to just buy a new truck?

Does anyone here have any experience with a similar situation? Most information I've found hasn't applied to this situation for one reason or another and I've learned to trust in the collective wisdom here. I know I'm not the only one with a GMT400 at this stage of its life.

I'd do a pan service on the trans and a seafoam on the engine, then figure out why it's falling on its face.

As far as modifying, you'd want to start with the basic bolt ons like headers, and if that's not enough maybe a small cam but I don't know how the vortec motors take to modifying, an lt1 cam and vortec heads is a very popular mild combo with the TBI guys.

Swap the engine for a 5.7L (350) Vortec, will be a noticeable difference. That would be the easiest way. An LS swap is another option, but costs will be higher, depending on what you find.

I would start with a compression/leakdown test. Find out what is making it sick.

In reply to dean1484 :

Not quite. In 97 the Vortec was basically an SBC with better heads and multi-port injection.

dean1484 said:

Vortec motors are LS motors. Put a 6.0 in it and enjoy the torque. Millage on the other hand will probably suffer but most people don’t drive trucks as economy vehicles.  

The ls truck engines didn’t come along till 99/2000. This is the first gen vortec which debuted in 96.

The confusion arises because they also call the newer truck LS motors Vortecs, but as stated above, the L30/L31 are SBC with vortec heads and E36 M3ty fuel injection.

I would also second a recommendation to swap in a freshened L31.  Should only cost a few hundred bucks at a junkyard for a good usable core.  Some had 4 bolt mains, all were roller cams. 

The injection/intake system is the letdown, as are the factory valve guide bosses, which limit the total gross valve lift to somewhere below 0.500", but the 5.7s did 255hp stock with 335tq.  Comp sells a kit to trim the guide bosses down, which, when combined with a very mild cam, a valve spring set to match, and a valve job, should be worth another 20hp easy on a healthy 5.7.  You can get really fancy and repin the ecu harness to accept a 0411 ecu (from an L31 van), but you'd need the ecu, front crank sensor/timing set and cover, some wiring mods, and someone to tune it all to work together.  At the end of the day, the stock injection system only can supply about 300-ish HP worth of fuel, so it doesn't make sense to do too much.

Your spider injection system may need replacement.  The high ethanol content tends to gum them up if they sit for a time.

How’s the rest of the truck holding up? At some point you’re going to need to look at the suspension and such, all of that plays into the decision. 

2002maniac said:

In reply to dean1484 :

Not quite. In 97 the Vortec was basically an SBC with better heads and multi-port injection.

And in its day it was a truck motor to behold.  I’ll never forget going to lunch with John Boy (that was his name) when I worked in Richmond, Virginia in the ‘90’s.  He had a brand new Z-whatever 1500 4X4 with the then new Vortec.  He punched it on I95 and it didn’t respond the way pickups did back then.  It pulled out like a Trans Am or Mustang GT.  I couldn’t believe it.

Not too many weekends after that he downed a few too many beers and managed to barrel roll it.  Darn near snuffed himself out.  A sober man wouldn’t have made it.

Damn.  It sure was fun being a redneck back then.

Right now I'm thinking about higher ratio lifters

Rockers

150k isn’t enough to write it off due to miles.....   I’d echo the suggestions to look to fix the problem(s) 

305s get no love. For simplicity and cheapness, a 350 is the best bang for the buck if you want more power. Toss in a decent intake and an aftermarket injection setup like a holley sniper or such and just drive. Could be done for under 2k all in I think, but you gotta decide how much the truck is worth. Rust? Worn out suspension/bearings/brakes/whatever. A mild cam and a home rebuild is easy and cheap, but won't net much more power without head work/$. And programming. Damn new-fangled fuel injection.

My boss has close to 275k on his 98 with the original vortec 5.7 and 4l60. His also gets a (gasp) transmission flush every 50k miles and that's seemed to have kept it happy doing everything from daily driving to towing. It's weird that at 150k your having engine issues, I'm a Ford fanboy but that's still pretty much the basic small block chevy and should live for a long time with routine oil changes. What oil are you running in it?

Just to clear something up... Vortec is a fancy trade name.  It applied to dozens of engines including everything from a 4.3 V6 up to a big block.  Its like Ford calling their V8s and V10s the Triton despite the changes over the years.

The 5.0L Vortec is not really in the same ballpark as the 5.7L.  When GM updated the 5.7L, they used heads that were way better. They trumped the L98 heads by a full 21% better intake port flow without adding much volume.  Then they kinda said "well, we should do something with the 5.0L" so they sprinkled fairy dust on it and called it a day.

I always recommend not trying to upgrade a 305 in any way.  Actually, I tend to make fun of people who do.  The 305 is a small bore.  It doesn't matter how much head work, cam work, or porting work you do, it is a very small bore with limited room for valves to take advantage of breathing.  You can spend $1000 trying to make a 305 perform like a 350... or you could buy a junkyard vortec 350 for $500 and direct swap it in an afternoon.  The 305 is only a little bit smaller than the 350 in displacement, but since the entire difference is in the bore size, it will always be a wheezer.

The "REAL" Vortec heads (castings 906 and 062) were found on 96-98 5.7L only.  They used the same exact port that GM designed for the iron LT1 heads in 1993 used in B-bodies like Caprice and Impala SS.

There really is zero point in reviving and upgrading a 5.0L.  Buy a 5.7L and drop it in.  You'll be getting more power, more torque, more potential, and heads that can actually support some upgrades.

If you do decide to swap in a 5.7, sell the  5.0 vortec as a core, the marine end is having a hard time finding viable cores for rebuilding,

I recently took a part time job in an engine shop, couldnt believe the scarcity of a 305 on the marine side

i 

In reply to Curtis :

Good information. I figured the 305 heads were similar, but that makes sense. 

In reply to dropstep :

I should be clear that the engine isn't really in bad shape as far as I can tell, though a compression or leakdown test would probably make sense. The top end may have always been the way it is now, but in the context of modern trucks it feels very underpowered.

I use full synthetic and I recently had a blackstone analysis done. Apparently a small amount of coolant is getting into the oil so I'll have to figure out what's causing that, but otherwise all was well. The transmission fluid seems clean and fresh, but I may replace it soon.

stylngle2003 said:

The confusion arises because they also call the newer truck LS motors Vortecs, but as stated above, the L30/L31 are SBC with vortec heads and E36 M3ty fuel injection.

I would also second a recommendation to swap in a freshened L31.  Should only cost a few hundred bucks at a junkyard for a good usable core.  Some had 4 bolt mains, all were roller cams. 

The injection/intake system is the letdown, as are the factory valve guide bosses, which limit the total gross valve lift to somewhere below 0.500", but the 5.7s did 255hp stock with 335tq.  Comp sells a kit to trim the guide bosses down, which, when combined with a very mild cam, a valve spring set to match, and a valve job, should be worth another 20hp easy on a healthy 5.7.  You can get really fancy and repin the ecu harness to accept a 0411 ecu (from an L31 van), but you'd need the ecu, front crank sensor/timing set and cover, some wiring mods, and someone to tune it all to work together.  At the end of the day, the stock injection system only can supply about 300-ish HP worth of fuel, so it doesn't make sense to do too much.

I vaguely knew about the limited lift, but this is all good information. Thanks. Will the current computer be happy with a 5.7 or should I try to source a 5.7 computer while I'm getting the motor?

Is there a GRM way to ditch the crappy intake system, or will that cost more than an LS swap? I've heard something about marine intakes with conventional externally mounted injectors...

In reply to Run_Away :

There's this thing for $400;

https://sdparts.com/i-23896057-sdpc-sd3816-tpi-vortec-lower-intake-baseplate.html

I imagine there's time with a die grinder ahead to get that intake lower manifold and 305 "Vortec" heads to match.  Carb intakes are around 1/2 that much. 

If it's not burning oil or showing other wear signs it might really just needs a cheap timing chain set to wake it back up (as much as a 305 will anyway), they're only oiled by splash/mist on a stock SBC so they don't last forever. Pretty easy to check the backlash by popping the distributor cap off and rocking the crank back and forth, more than a few degrees of crank rotation to move the rotor is bad.

Coolant traces in the oil is probably intake gaskets, I don't think GM figured out how to make them last on any V6/V8 until the LS1 came out, a few stop leak tablets might stop it without having to rip the top of the engine off.

I'm definitely planning on changing the intake gaskets and rechecking the oil further down the road. The timing chain is an interesting possibility as the culprit for the lost power. A marine intake is also interesting if I go the 5.7 route (I likely will).

I should reiterate that I really don't want to venture too far away from stock in terms of civility. I like the fact that my truck doesn't sound like every barely running truck with dual exhausts in Texas. 

As a half-update to the thread, I recently picked up a 5.7 Vortec and 4L60E, both needing rebuilding. I still need to double check the head casting numbers and find out if the block has two or four bolt mains. Hopefully this will happen tomorrow, then the motor will go into storage while I head to work for a few months.