Engine Options for 94 Z71

[beertestr]

Hey all, just getting back to the site, I have a new project I am considering. 94 SCLB Z71. Motor is toast, but the 4L60E is fresh with some beefed up internals (Beast Shell etc..). Engine bay is slightly modded for a Holley Commander 4-barrel TBI unit, I think the fuel lines have been reworked, no biggie. Truck has a custom exhaust with long tubes.

I am considering what I am going to do to get it on the road. Obviously, the need here is to pick what engine I am going to put in there.

Engine Options:
1 - In my shop I have a forged 383 Vortec motor. Complete engine with intake, accessories, Gibson shorty headers from a 99 tahoe, so they should fit np. I will be getting the harness and PCM from the guy I got the motor from in the next few days.

so..... 1a) Get a Vortec TBI intake and slip this critter in there. I'll have way more long block than a stock TBI intake and TBI unit can make use of so it'll be really choked.
1b) Adapt the 96-99 Vortec harness controller and accessories. The stock CPI intake is a choke, I am not confident that the fuel system can keep up. There is a Vortec head dual plane intake available drilled for fuel injectors, the plan would be to use one of my LT1 fuel rails and rewire for conventional injectors, and fit the TB to the intake via and adapterplate or one of the 90 degree intake elbows they have.

Either option, I should be able to reuse the headers in the truck.

2- In my shop is my forged 350 LT1. I have it for sale, but it is FRESH, less than 200 miles on it. It's boost ready too. I have 2-3 engine harnesses (2 b-car one F-body), so I have options in terms of wiring. Again, the wiring can be adapted, and I can rework the fuel lines to work with LT1 quick connects.

3- Yank the 4.8L out of my 93 Sierra, and all the other parts I put on it for the swap, bolt it into the 94. I do not expect the wiring to be very different 93-94, the swap is damn near a drop in. Aside from the y-pipe clearance issue that I posted in another thread.

So clearly, I have options. What's the group consensus? Your vote <kinda> counts.

I really want to do the 4.8L, but I am concerned about the y-pipe routing. I want to minimize down time without a pickup, so tearing one apart to get the other running is an issue.

[txarkitekt]

Hmmm...interesting options.

Well, you obviously are well versed in Gen II TBI motors. The forged 383 will be nice--for sure! But it will be a slight pain to get it all in there and working correctly.

And then you have the Gen III motors. Don't get me wrong, there is a soft spot in my heart for those old SBCs, but once you get acclimated to the Gen III way of doing things, you'll never go back. Options are unlimited, and those motors respond better to mods.

If it was me, I would sell the forged 383 and forged 350 motors. I would not suggest putting the 4.8L behind the 4WD RCLB truck, so leave the 4.8L in the 93. With the money you gain from selling the other motors, buy a (2001 and up) 6.0L (LQ4/LQ9). Since you have already swapped a Gen III into an OBS, your swap will be easier than before and you are starting off with a much stronger motor.

P.S. 95 9C1 with T-56??????? Pics please!!!!!!

[beertestr]

Hmmm...interesting options.

Well, you obviously are well versed in Gen II TBI motors. The forged 383 will be nice--for sure! But it will be a slight pain to get it all in there and working correctly.

The biggest pain with the 383 is getting an induction system that will keep up. Wiring difficulty ranges from easy (stock TBI) to not any more than the 4.8L option, exept that the 4.8L is likely ready to drop in.

FYI, a GenII engine is the LT1/LT4/L99. The Vortec 5.0 5.7 L31/L31 in GM vernacular is the Gen1-E.

If it was me, I would sell the forged 383 and forged 350 motors. I would not suggest putting the 4.8L behind the 4WD RCLB truck, so leave the 4.8L in the 93. With the money you gain from selling the other motors, buy a (2001 and up) 6.0L (LQ4/LQ9). Since you have already swapped a Gen III into an OBS, your swap will be easier than before and you are starting off with a much stronger motor.

I am fine with the 4.8L. Keep in mind the old 5.7 TBI in the truck was 200HP and 310 ft-#, the 4.8L is 285/295 HP/TQ. It'll be fine. In my 2WD, it towed my caprice fine at 80 in 4th gear with 3.42's and 31" tires. Getting the setup working in the truck is the challenge, swapping in a higher power long block is a piece of cake. As for keeping the 2wd truck together, it's rusted out pile these days, so I was going to strip it after the Z71 is up and running anyway. The 4.8L was a NEW engine when I put it in, it has maybe 5000 miles on it now, so it's fresh. Bolt in and go.

I hear ya though, I just sold my LQ4/4L80E (2wd) that I had sitting in the garage right before I found this truck. I have my eye on an LS2 TBSS engine,and an LQ4 right now. While I would love to sell the 383, I'm not getting any nibbles. It's a boost ready motor, so the pricetag on the shortblock is higher than what people are willing to pay for. I have had it listed down to $2500, which is about $3k under the money in it, nobody.. oh well. The LT1 is up for sale, and might be sold, but it's a viable option.

Overall, if I find out I can fit my stock 2004 4.8L y-pipe around the 4WD, the 4.8L is going in.

P.S. 95 9C1 with T-56??????? Pics please!!!!!!

Sure... no pics of the install handy. I just sold the car as a roller 2 weeks ago.

[txarkitekt]

The biggest pain with the 383 is getting an induction system that will keep up. Wiring difficulty ranges from easy (stock TBI) to not any more than the 4.8L option, exept that the 4.8L is likely ready to drop in.

FYI, a GenII engine is the LT1/LT4/L99. The Vortec 5.0 5.7 L31/L31 in GM vernacular is the Gen1-E.

Mental note taken.

What part of the induction is making this hard? Why not a Vic Jr?

I am fine with the 4.8L. Keep in mind the old 5.7 TBI in the truck was 200HP and 310 ft-#, the 4.8L is 285/295 HP/TQ. It'll be fine. In my 2WD, it towed my caprice fine at 80 in 4th gear with 3.42's and 31" tires. Getting the setup working in the truck is the challenge, swapping in a higher power long block is a piece of cake. As for keeping the 2wd truck together, it's rusted out pile these days, so I was going to strip it after the Z71 is up and running anyway. The 4.8L was a NEW engine when I put it in, it has maybe 5000 miles on it now, so it's fresh. Bolt in and go.

I hear ya though, I just sold my LQ4/4L80E (2wd) that I had sitting in the garage right before I found this truck. I have my eye on an LS2 TBSS engine,and an LQ4 right now. While I would love to sell the 383, I'm not getting any nibbles. It's a boost ready motor, so the pricetag on the shortblock is higher than what people are willing to pay for. I have had it listed down to $2500, which is about $3k under the money in it, nobody.. oh well. The LT1 is up for sale, and might be sold, but it's a viable option.

Overall, if I find out I can fit my stock 2004 4.8L y-pipe around the 4WD, the 4.8L is going in.

Ah, a newer 4.8L...gotchya. And with that 383 laying around plus your 4.8L, I can see why you don't wanna buy another motor... Well, since its down to this--I say the 4.8L.

Is it a stock motor?

NICE. I bet that could get up and move! And a 6 speed manual would make that even MORE fun!!!

[beertestr]

What part of the induction is making this hard? Why not a Vic Jr?

There is a Vortec Super Victor set up with the injector bungs already machined in. Converting to a MPFI setup would take care of fuel and air delivery shortages.

I think the 4.8L is the best route. It's bone stock, the engine, manifolds, y-pipe and exhaust system are all low mileage 2004 Silverado parts. All came off my buddies 04 SCSB 5-speed truck we turned into a Silverado SS Clone/mutant.. a body config they never built. he bought the truck, trailered it home, and ripped the motor out. A few months later, it found a home in my 93.. When the right 6.0 falls into my hands, I'll be poised to drop it right into the 94..

[WARLOCK]

I vote throw the 4.8 in there with an aftermarket cam. U wont be sorry.

[txarkitekt]

There is a Vortec Super Victor set up with the injector bungs already machined in. Converting to a MPFI setup would take care of fuel and air delivery shortages.

I think the 4.8L is the best route. It's bone stock, the engine, manifolds, y-pipe and exhaust system are all low mileage 2004 Silverado parts. All came off my buddies 04 SCSB 5-speed truck we turned into a Silverado SS Clone/mutant.. a body config they never built. he bought the truck, trailered it home, and ripped the motor out. A few months later, it found a home in my 93.. When the right 6.0 falls into my hands, I'll be poised to drop it right into the 94..

So with a little work, the 383 could be viable. And the 383 should end up making more power.

But it sounds like your heart is sold on the 4.8L... That little booger can actually scream pretty well if the right mods are paired to it. I really wouldn't worry about the exhaust too much. Not 100% sure, but you should be able to get a set of shorty headers to fit under there and you can have a a custom exhaust designed.

That SS clone sounds like a bad mofo. Did that guy keep the manual tranny configuration?

[beertestr]

So with a little work, the 383 could be viable. And the 383 should end up making more power.

But it sounds like your heart is sold on the 4.8L... That little booger can actually scream pretty well if the right mods are paired to it. I really wouldn't worry about the exhaust too much. Not 100% sure, but you should be able to get a set of shorty headers to fit under there and you can have a a custom exhaust designed.

I can fab an exhaust, not really a big deal, just more work. I prefer stock manifolds on a truck. The extended heat you dump into the exhaust when hauling makes me want troublefree durability over the few HP I would gain on the little 4.8. Keep in mind the 6.0 manifolds are the same as the 4.8L. I set my 93 upwith HD fuel lines and hydraulic hoses to the aux trans cooler. The plan for the 94 is a clean appearing, but still very capable truck. It's main use is weekend duties to the landscape supply, rock supply, moving car parts around, and be dead nuts reliable doing it. I'll attach a pic of the "new" truck.

I am not totally sold on the 4.8L, but while it's just a dinky little guy, it's also the freshest motor I have, and likely the easiest to get running in the truck properly. I do have a soft spot for the 4.8L for some odd reason. It's a nice running little motor, barks the 31" tires on my Sierra on the 1:2 (3.42 gears too). I'd like a 5.3L a 6.0 would be nicer, but if I have to put into DD duty, 5.3 is as big as I would go. It tows great with the 4.8, I put an 2003 SSR converter in it to get it off the line a little better, and have towed my Caprice on the trailer at 85 mph in 4th gear.. Not intentionally, I thought the truck had 3.73's when I cal'd it, so 75 mph indicated was a weee bit faster in reality. That, and the hard work setting the truck up for a LSX will be done using parts I already have/fabricated. The only things I may need to do is:

1) Modify the motor mount adapters, the ones I have are for a 2WD LSX based 4L60E. They are a little longer than the older 2wd small blocks. I am using the original 1994 trans this time, so along with the flexplate spacer, I think the engine is going to sit a little different fore-aft. Not 100% sure though. Try and see.

2) Might have to work out the exhaust, it might just bolt in too.

3) There was a 3rd item I thought of, but I just forgot.

The 383 will need the top end put back on and either wiring for the Vortec controller, or converting it to TBI, or some version of batch fire MPFI. Doable, within my skills, but more time consuming. Part of me kinda wants to do it still... we'll see. I also have the 383 up for sale or trade, so while it would be nice in terms of power, it will be nice to have $$ in had for other projects, like my 53 F-100.. we'll see.

That SS clone sounds like a bad mofo. Did that guy keep the manual tranny configuration?

Dunno if you have ever been on on SilveradoSS.com, but He goes by ImpoSStor SS. Here's a pic from the Detroit Autorama.

First incarnation (second counting the original factory build) was a LQ9 with LS6 heads, and the 2002 LS6 cam (aka LS2 cam). Long tubes, custom dual exhaust. 4.56 rear, Baer Brakes front and rear, and a T56 modified with a Viper Tailshaft housing (puts the shifter in a very good location for a Silvy). We knew some of the guys that made the custom cladding for the standard cab GM show truck, so he had some custom panels made up. There are several guys out there with these panels now, he was the first. I did the cal on the truck on the NA 6.0L. The next upgrade was a Wheel to Wheel Radix blower kit (his truck was one of the test-fit vehicles for the kit). 540 ish HP at the wheels until he put a hole in #7 piston. It's proof that you can run boost on an 10.9:1 motor.... for a while. Right now it's waiting for a motor build... pending stabilization of the economy/auto industry here in Motown.

[txarkitekt]

Ok, well run with the 4.8L. Like you said, sell of the other motors for cash to redo the F100.

As for the 3 probs/questions you have, I am sure there are guys on here in the Swaps section that have run across your issues before and they can help you remedy them.

And while the 4.8L is out, throw a cam, springs, and pushrods that has a low-end power bias. UD pulleys also help free up low end power. Do a little port/polish on the TB and then get it all tuned up. It will raise your eyebrows for sure.

I have seen that guy's truck on SSS. What psi was he running until #7 went kaboom? Must have been at least 10 psi...cause I have known people to run the 2.8 pulley and almost near making that power level without having that plaguing #7 issue...

Nice little 94. 18" Escalade wheels? And put the '95+ mirrors on that thing!!!!

[beertestr]

Well, looks like it's going to be the 4.8L for now. The 383 has not been touched, and I am considering saving that one for a 0411 PCM conversion and a turbo..

I was working a deal on a burnt LQ4 out of a Denali, but the guy would not budge on the price. $300 was more than I wanted to spend on a motor that I couldn't turn 360 degrees...

Time/weather permitting, I hope to finish yanking the TBI 350 out of the 94, then preparing to pull the 4.8L out of the 93 (aka perforated pickup).