New engine for 94 Silverado
 

My older brother owns a 94 Silverado that is rust free but he’s having issues with the engine. It’s a pooch anyway and he’d like to replace it with something with more hp and torque. It’s a 5.7 TBI engine so he wants something that will bolt right in and mount up to the existing trans. Where’s the best place to pick up a replacement engine with 300+ hp?

Re: New engine for 94 Silverado
 

A stock engine with a decent cam and headers will be 300hp.

Re: New engine for 94 Silverado
 

Nothing is going to drop in with 300hp and stock TBI unless he carbs it. You'll need an engine that's designed to put out 300+, a chip, and probably a new regulator spring and fuel pump.

The closest you'll find is the 383 that GM makes as a TBI replacement, but I believe that still needs at least a chip.

Re: New engine for 94 Silverado
 

Agreed. Closest thing is a L31 vortec long block. Around $1,900 and best info is 255 hp. There were versions rated up to 330hp from what I read but not this one.

But to put it in the a TBI truck is not just a bolt in. Well the engine will bolt in but you have to have different intake manifold to fit the heads, plate for the TBI and you will HAVE to have a new tune on the computer to make it work.

I am going to buy one for mine and possibly swap out the cam. But this is not going to be a bolt in swap. It is going to take some tuning to make it all work together.

Re: New engine for 94 Silverado
 

Thanks for the replies!

I talked with a tech from Scoggin Dickey and he thought my brother could go to the L31 Vortec which has 250hp and 330tq. He would have to purchase a manifold that would accept his existing original TBI. Headers might add a few more hp. The current motor I believe is 195 so it would be an upgrade.
I think he should go with a 383 and add a Holley or Edelbrock FI system.

Re: New engine for 94 Silverado
 

I put a set of headers on a truck I had 20 years ago. Was a 90, 350 with a 154k miles if not more. Only thing I did was put headers on and get rid of the cat, and was like a totally different truck. Felt like the torque was doubled. Think they were Flowtech's.

Re: New engine for 94 Silverado
 

I have a 95 C1500 with 323k on the original TBI motor. I have headers, AirAid intake, MSI coil, and full stainless high flow exhaust. It made a huge difference in the TBI 350.

I also did the L31 conversion on my 95 Yukon using a crate motor, the TBI to Vortec manifold, fuel pump, spring, chip, etc. I have the same external setup of headers, MSI coil, intake, etc. on it as I do the truck. It's a considerable increase in power and although I had to fabricate some items and figure out a few things that are a tad different, it was well worth the investment in time and money.

Re: New engine for 94 Silverado
 

Glad to hear someone confirm what I knew... well, hoped I knew. My 93 has a loose rod bearing, knocks before oil pressure comes up. Hoping to swap it out this spring. Was driving home today thinking about the swap and how it wouldn't take much for the swap to gain 100 hp over the stock Suburban engine.

Re: New engine for 94 Silverado
 

Awesome info! I’ll pass it on to my brother.

Re: New engine for 94 Silverado
 

Mike, would it be possible to get the part numbers for all the components you used for your truck setup and your L31 Yukon setup? This would make my brothers upgrade much easier. Thanks man! You can email me at bdshuggy@yahoo.com if you’d rather do that.

Brian

Re: New engine for 94 Silverado
 

I can post it here for anyone else who might need it:

-GM TBI to Vortec manifold 12486572
-Driver's side exhaust manifold or headers with EGR tube. I'm went with Gibson GP102S (if you care about EGR)
-EGR tube for Vortec 10242876 (Dorman 598-200) (if you care about EGR)
-Chip kit from tbichips.com - pcm chip, 18psi spring, fuel pump
-Intake bolts (8) - 12550027
-Intake gaskets - MS901312
-Dizzy with melodized cam gear - https://www.summitracing.com/oh/part...0200/overview/
-Dorman 46001 PCV tube
-3/8 npt to 1/2" nipple right angle - This was for the brake vacuum tube
-Vent tube to tbi from valve cover
-5/8 nipple to 1/2npt - for coolant. I think I used 2.

Other notes:

I had to modify the MAP sensor and throttle cable/cruise brackets for the new manifold bolt pattern. IIRC, the MAP bracket just needed to be bent a little, and the throttle bracket needed to be bent over the other way, trimmed, and a new hole for the intake bolt drilled, then painted.

All of the accessories bolted right up, no issue there. For the coolant hoses, I ran a hose from the rear outlet to the water pump, the front outlet (on top) to the heater core, and the heater core out to the radiator just below the fill. My temp sender is in the front of the manifold.

It's not a bad swap, just lay everything out ahead of time especially the brackets. Get some from the junkyard or eBay if you can. If I think of anything else, I'll post it here.

Good luck!

Re: New engine for 94 Silverado
 

If he decided to stay with the original TBI engine would those same Gibson headers work?
We don’t get emission tested here so EGR stuff could probably get yanked unless it throws a code. Can egr stuff get turned off with a tune like LS computer tunes can?

Re: New engine for 94 Silverado
 

You could use this Gibson headers, but then gonna have a hole where the EGR tube would go. just get the headers for the year of the truck. Mine went on in the driveway laying on the ground. I put a piece of 3" pipe in place of the cat, everything went on fine and bolted right up. Made it louder and gave it a lot more power.

Re: New engine for 94 Silverado
 

Gibson shorty SS headers without EGR are the GP100S. Your choice though, I have Edelbrock shorty SS on my truck and the Gibson SS on my Yukon. They really look like they were made by the same company. The only difference is the EGR tube on the Gibson, and the Gibson have the built in donut which I really like.

Re: New engine for 94 Silverado
 

Mike,

Trying to find a price on the 12486572 manifold but Google keeps coming up with a 12496821 manifold. Was the 572 replaced with the 821 at some point?

Re: New engine for 94 Silverado
 

Same part, different numbers. They are the same manifold from what I can tell. Probably a plant shift or something like that.

One other thing I remembered is you'll need a 3/4" plug for the timing cover. The Vortec uses a crank sensor that bolts in there, but you won't need it. Plug the hole otherwise oil will get out. I used some RTV and tapped it in with a long socket.

Re: New engine for 94 Silverado
 

FYI you can get just the melonzied gear strait from gm for like $30 last time I bought one.

Re: New engine for 94 Silverado
 

I had a hard time finding the right size gear that fit my distributor shaft, so I just went with a whole new dizzy.

Re: New engine for 94 Silverado
 

Its the oem gear for vortec small blocks, fits any standerd distributor. I've used them on several 70-80's models, perhaps TBI's are different some how?

Re: New engine for 94 Silverado
 

Everything that Summit carried was either too small or too big for the distributor I had. Now I had an aftermarket one already so maybe that's why. Either way, I was unsure of the overall condition of the old distributor so a full replacement was in order anyway.

Re: New engine for 94 Silverado
 

How much does he want to spend?
From what I'm reading here, the price is going to be high.

I had my '95 2500/5spd, block crack not long ago and long story short, NEEDED a motor for my daily "quick".
All I had built up at the time is a '62 283 (forged .060 over), Comp xe268 cam with some self ported 062 Vortec heads, Ebay Vortec spread bore intake. TBI adapter and the rest of the accessories and Flow-tech afterburner headers modded to true dual exhaust, with 30+" glass packs
EVERYONE said it wouldn't work, but the only issue was it ran pig rich on idle. and got around 16-17 HWY mpg! and sounds MEAN! (3.42 14 bolt, 285 tires, so it's right at @2000rpms going 70. AND 6000lbs with me, and would've eaten the orig 350's lunch)
And all in for about $700-$900.00 and my time. (almost a week)

Brian from TBI-chips said that he would need the truck to work out the fuel maps and that in itself wouldn't be cost effective. (actually he wouldn't touch it) Thought about going with 4.3 V6 injectors/747 ECU but would rather have it rich than LEAN driving
So, I drove it for almost a year, changing the oil sooner because of fuel condition.
Now have installed a Rochester and a china HEI (just 'zip-tied' the wiring off to the side) and now it's leaner at idle but dropped to about 14mpg and now almost 1.5yrs. Waiting to get my CR-v running so I can install my '80 406 for it for a lot more torque. (swapping the top end parts)
The TBI years is a great platform to swap stuff into. Because it's CHEAP CHEAP, and parts are only a search on Craigs list or Pull-it away..
Heck, you could even do a Big Block Caddy and still use the TBI and your trans!!

BUT, where I am, I don't have to worry about Liberals forcing folks to purchase NEW just to pass emissions.

E

Re: New engine for 94 Silverado
 

Just noticed this and curious about your experience with Harris. Not trying to start anything but I have read a lot of horror stories from people that had really bad experiences with his tuning.

You can always find negativity on the internet but I have seen enough I am afraid to try him. Several stories of being in 5 or 6 chips from him and their car/truck still not running right. Many saying they couldn't see any improvement from chip to chip. A couple where the people sold the vehicle and gave up.

Re: New engine for 94 Silverado
 

If you're asking me.. I brought this to his attention and he pretty much said that
"some people follow directions, and some don't. And expect PERFECT RESULTS.."

It took a couple calls/emails, but finally got to actually speak to him for a while and by me also having a side business of offering a service to the public, could see where he's coming from.
He was polite to me, but basically told me that my combination of parts would take a long time and LOTS of cash to figure it out, and then might not be all that happy with results.

If you're going pretty much "STOCK", I think he would be able to suit you. But like anything that requires and ingredient list, the more you add, the worse it can get in a hurry. And can send you down rabbit holes that are going to get expensive.

Just keep it simple. Cold/ram air/ Header(s) are usually the first 'changes' people make.
A GOOD close friend used him and it took a couple chips, but ended up totally happy and suggested to me to do the same. (it's just I'm more hard headed and can't leave well enough alone)

BUT... What are you starting with? A P.O.S from C/L, or a vehicle that you know/have history/service knowledge since new? TOTALLY stock or NO? (then, what parts aren't?)
ALL sensors and ECU playing nice together?
ALL vacuum lines in good shape?
Good Grounds and wiring not all chewed up by ___? (DAMN idiots that install car alarms are one major culprit of electrical gremlins)
How many miles/years on _____ etc.. (sure it might be a low mileage, mint vehicle that sat in a air conditioned warehouse. but if the fuel lines/system are all gummed up well..)
Remember, they're pushing 30+yrs old. AND, even fuel ratings can play a part.

Gotta jet.
e

Re: New engine for 94 Silverado
 

I've had no issues with his tuning. But then again I'm running something pretty common so it's a pretty easy tune, and it's been around long enough to get right. I was looking for more power, same or better gas mileage, and a simple setup. This does the job and fits all of the criteria.

Re: New engine for 94 Silverado
 

Good to hear Mike.

rockosocko, I have no experience so of course I don't know. But have read on another tuning forum of two people that had paid for 5 or 6 chips from him and gave up. They used one of two guys on the forum and first or second chip and they basically say it was like Night and Day the difference in the vehicle. Lot of similar stories.

I run a small business and have worked with the public so I know how hard some people are to please so I take things like this with a grain of salt. But I keep reading it over and over and that is when I start to think there is at least some truth to it.