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Dootz
Dootz New Reader
1/3/19 11:09 p.m.

Was thinking about buying a '90 model with a beat-up L98, and swapping in a newer motor (aluminum weight, better power throughout, mods galore). Would I just go with a typical swap kit? Bring in the 4L60E too?

Pete Gossett
Pete Gossett GRM+ Memberand MegaDork
1/4/19 5:27 a.m.

In reply to Dootz :

You need a C5 oil pan & accessory drive setup. The motor mounts are available pretty cheap. It’ll bolt up to the 700r4 and there are kits to run it behind an LS.

When I researched it buying a salvage C5 was the most cost-effective way to do it. 

Patrick
Patrick GRM+ Memberand MegaDork
1/4/19 7:27 a.m.

There is an adapter to run the 4 bolt tail housing on the newer trans, which is how I would do it versus trying to make the tv cable work.  

Basically by the time you buy the l33 and find all the required vette specific accessory parts you can buy an ls1/6 corvette dropout.  

Curtis
Curtis GRM+ Memberand UltimaDork
1/4/19 10:44 a.m.

The trans bolt patterns for LS and SBC are a little different.  You'll be missing a couple bolt holes on the 700r4, but it is done all the time and isn't a problem.  You'll need the correct TC to go between the LS and 700r4.  (different belhousing depths).  Then just flash the ECM for a manual trans application and let the 700r4 do its thing.  You will need to find a way to adapt the TV cable to the throttle.  If you have a drive-by-wire L33, make up some bracket to control the cable with the foot pedal.  If you get (or convert) a manual throttle L33, there are kits to adapt your cable to the TB.

The 4L60/5E would be a direct bolt-in though and a no-brainer.  The ECM for the LS controls the speedo but the one in your dash is set up for a direct signal from the VSS in the 700r4 so there may be some adaptation there.

The LS needs a bit more fuel pressure than the TPI if I recall correctly.  I forget if the TPI has a fuel return line from the regulator but I think it does.  If it doesn't, look to the C5 regulator.  It mounts under the frame closer to the tank and it makes it a little easier to plumb a return.  You may need a Walbro 255 pump in the tank since the L98 pump may not have the oomph to keep up.

Pete Gossett
Pete Gossett GRM+ Memberand MegaDork
1/4/19 2:50 p.m.
Patrick said:

Basically by the time you buy the l33 and find all the required vette specific accessory parts you can buy an ls1/6 corvette dropout.  

And by the time you have a reasonably reliable running/driving car you could have just bought a C5, be on the road/track that much sooner, and be faster too(presuming you’re not budgeting $$$ to fix the C4’s suspension).

Patrick
Patrick GRM+ Memberand MegaDork
1/4/19 3:14 p.m.
Pete Gossett said:
Patrick said:

Basically by the time you buy the l33 and find all the required vette specific accessory parts you can buy an ls1/6 corvette dropout.  

And by the time you have a reasonably reliable running/driving car you could have just bought a C5, be on the road/track that much sooner, and be faster too(presuming you’re not budgeting $$$ to fix the C4’s suspension).

Very true, but I REALLY like how a 90 looks vs a c5. But everything really is better including ingress and egress.  Getting out of a c5 is like getting out of a buick when compared to a c4.  It’s kinda silly to ls swap a c4 and throw c5 brakes at it when you quite literally could buy a c5 for the same price and be driving immediately 

fidelity101
fidelity101 UltraDork
1/4/19 3:19 p.m.
Patrick said:
Pete Gossett said:
Patrick said:

Basically by the time you buy the l33 and find all the required vette specific accessory parts you can buy an ls1/6 corvette dropout.  

And by the time you have a reasonably reliable running/driving car you could have just bought a C5, be on the road/track that much sooner, and be faster too(presuming you’re not budgeting $$$ to fix the C4’s suspension).

  It’s kinda silly to ls swap a c4 and throw c5 brakes at it when you quite literally could buy a c5 for the same price and be driving immediately 

This has always been my understanding. just because its different doesnt it make it better but isnt every car just a swap of parts away from its newer model? and why dont we always drive those instead?

Curtis
Curtis GRM+ Memberand UltimaDork
1/4/19 3:28 p.m.
fidelity101 said:
Patrick said:
Pete Gossett said:
Patrick said:

Basically by the time you buy the l33 and find all the required vette specific accessory parts you can buy an ls1/6 corvette dropout.  

And by the time you have a reasonably reliable running/driving car you could have just bought a C5, be on the road/track that much sooner, and be faster too(presuming you’re not budgeting $$$ to fix the C4’s suspension).

  It’s kinda silly to ls swap a c4 and throw c5 brakes at it when you quite literally could buy a c5 for the same price and be driving immediately 

This has always been my understanding. just because its different doesnt it make it better but isnt every car just a swap of parts away from its newer model? and why dont we always drive those instead?

I have a significant soft spot for what he's proposing though.  I love taking what you have and making it what you want.  Sometimes it doesn't have to make sense.

Heck, I have a 66 Bonneville worth $500 that I already sunk $15k into and it's not even on the road.  I have taken perfectly good low-mileage cars and swapped engines just because I wanted it to be different.

Toebra
Toebra Dork
1/4/19 4:01 p.m.

Would it be easier to just swap the C-4 body onto the C-5 chassis?

Daylan C
Daylan C UltraDork
1/4/19 5:03 p.m.

Buying a donor truck, then front accessory brackets oil pan and intake surely doesn't eat up the entire cost of a donor c5. Besides a donor c5 leaves you buying a transmission. Actually this is where I remember most if not all l33s were in 4wd trucks, so the transmission bit is a wash. 

GTXVette
GTXVette SuperDork
1/4/19 5:06 p.m.

A Simple Rule of thumb, Any engine trans combo that may be considered Old School ...  Big Block, Small Block, carbed, PG 350 400 200/700 r4 Manual trans as in muncie, t-what ever, use a C4

  Any combo with an Ls Engine and 4l60/65 80 or anything that needs a computer to Operate just do the C5

 It is all about Money ,Plenty of it and you can do anything, this way you save time and money 

Pete Gossett
Pete Gossett GRM+ Memberand MegaDork
1/4/19 6:43 p.m.

In reply to Daylan C :

I was presuming we’re talking about an early C4 - swapping an LT1 car wouldn’t generally make as much sense - and the early C4s are just such bad cars, especially 84-86. The suspension doesn’t work very well, the chassis is a noodle, the electronics are E36 M3, the interior is E36 M3...yes, all that can be fixed(to a certain extent) or removed, but fixing it takes time and/or money.

I do agree that the C4 styling has aged better than the C5, but as I’ve mentioned before it’s like all the bad experiences of owning a neglected 30+ year-old exotic car, without being nearly as interesting. At least most of the drivetrain & chassis parts are reasonably cheap.

 

GTXVette
GTXVette SuperDork
1/5/19 8:06 a.m.

Pete Speaks from Experiance, Sadly...  THE Best Build thread of the year that Included Mikes AMC Build (Also Great). He Got close to having that Exotic Car, But little things wore him Out,  Because There were So Many, Not like He didn't try.

A Better Car To Start Could Have Givin' Us A Happy Pete, In Stead Of Bitter Pete      L O L !!!!1

Patrick
Patrick GRM+ Memberand MegaDork
1/5/19 9:50 a.m.

So I want to clarify.  When i said silly I mean from a logic standpoint.  But logic doesn’t work here.  This is GRM, we don’t do logic and i’m one of the worst offenders. 

I had a c4 for 10 years.  The wiring was brittle and the older i get the harder it is to get out of. 

The L33 used to be the hidden secret, but now everyone knows what it is and I have bought aluminum 5.7 LS1 engines for less than aluminum 5.3 are going for now.  It’s actually getting harder to do a budget ls swap, because the cat is out of the bag and the days of ebay being littered with low mile $199 4.8 $299 5.3 and $399 aluminum 5.3 are gone.  Now if you find one for that price you’re looking at 300k miles.

to swap a c4 requires piecing together c5 balancer and accessories, which ran me around $400 not counting power steering pump or air conditioning.  That was bare minimum alternator and bracket, balancer, tensioner, idler, and hoping my camaro water pump will work.  Power steering is going to add another couple hundred for pump, reservoir, and having lines made.  

Chances are the camaro oil pan will work, because i have verified it works in the c5.  I don’t think anyone has bothered trying.  But pan/pickup/windage tray/dipstick/tube are another $200+ used or new. 

Intake needs to be car, and ls1 intake/rails/injectors start at 400 and go up.  Used to be able to grab them for $20.  

Now you have all that stuff, you need to change to ev1 plugs for your car injectors, or run injector spacers because the truck injectors are shorter.  

Then you can get to exhaust manifolds.  I assume c5 ones work, i know there is no room for the truck ones.

so after all this our $1000(guess, i can not find one for less right now unless you buy a trailblazer or variant with a defaulted title loan for $500) L33 ends up around $2500, plus all the little stupid stuff that comes with taking things apart, because basically nothing that bolts to the block or heads fits.  When you start looking into c5 dropouts with harness and pcm and all accessories the pricing starts getting very attractive. 

Yes, i have done budget swaps.  I got one to the challenge by parting out a van and making some lucky trades and from hoarding parts and their receipts back when they were basically throwing out stock intakes and stuff.  It also helps that my $700 hptuners rig is a tool and not part of the car, but that’s still a large out of pocket expense.  But it’s hard to go cheap anymore and by the time you throw the price of the car, wiring modification, tuning, whatever transmission stuff you go with, you’re well on your way to a cheap c5 that will do everything(except look) better and probably has less miles than that truck 5.3 you find.  

Plus a c5 has more room for a roll bar

Ninja edit:  the 2nd listing under ls1 dropout on ebay is from a 99 c5 with 79k miles for $2759 with free shipping. 

Pete Gossett
Pete Gossett GRM+ Memberand MegaDork
1/5/19 10:39 a.m.

In reply to Patrick :

I forgot about exhaust. I’ve seen LS swap kits that contained both motor mounts & headers, and I believe you need something other than stock LS exhaust in a C4. 

Dirtydog
Dirtydog GRM+ Memberand Dork
1/5/19 11:11 a.m.

As a previous C4 owner, look into a C5.  Look for the best/cheapest one.  Drive, enjoy.   Save your labor and money to buy nice goodies for it.  I think there are plenty of ways to make it your own.

rdcyclist
rdcyclist GRM+ Memberand Reader
1/5/19 1:11 p.m.

^ +258k. Do what the Dog sez: Just buy a C5. I am amazed at how long GM built the C4. For its day, a pretty good deal but comparing it to a C5 is like about like comparing a Gen 4 Fox body Mustang to the present Gen 6. Night and day.

QuasiMofo (John Brown)
QuasiMofo (John Brown) GRM+ Memberand MegaDork
5/2/23 9:46 a.m.

Returned from the dead only because it was a Top10 Goofle search and I wanted to throw in some deets on what can be done on a "relatively" small budget.

Adding a L59 Flex Fuel engine to a 1991 L98/700r4 car currently. Items being used:

-ICT mount plates $30

-Prothane mount inserts $60

-LS1 intake $60

-LS4 fuel rail with AN adapter $125

-L59 Fuel rail cap adapters $20

-ICT -1 G8/CTS-V alternator/PS bracket (uses C4 power steering pump) $175

-F body pan $169

-C5 manifolds (C6 will also work) $60

-Return regulator with AN adapters and lines $160 

-Nathan Wei harness $270

-Amazon LS truck cold air kit $60

-Flywheel with bolts and spacer $90

-Detent bracket $25

Still looking for a "not truck" throttle valve. I will also be running a little Truck Norris cam and decapping the Flex Fuel injectors.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
5/2/23 5:52 p.m.
Toebra said:

Would it be easier to just swap the C-4 body onto the C-5 chassis?

All of the no.  The frames are shaped a lot differently, which is why you get into a C5 like you are getting into a car, and you get into a C4 like you are getting into a kayak.

 

Re:swap... IIRC the late C4s actually do use the upper bellhousing bolt for a seven-bolt bellhousing pattern, so they have 100% of the LS bolt pattern.  Not that it matters because as pointed out, the easy button is sticking the C4 tailhousing on a 4L60E.

I am certain that a pre CAN all the things LS PCM's speedo output is engineered to drive an electronic speedo that read a 4000 pulse/mile signal from a VSS.  Specifically so GM could slot electronic transmissions in to existing architectures.  Done it, worked fine.

QuasiMofo (John Brown)
QuasiMofo (John Brown) GRM+ Memberand MegaDork
5/2/23 9:32 p.m.

In reply to Pete. (l33t FS) :

I'm far less concerned with the speedo, far more so with the lockup and tach signal. At worst my Android stereo will run Torque. 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
5/2/23 9:45 p.m.

In reply to QuasiMofo (John Brown) :

Gen III computer will work the tach, standard four pulses per revolution.

If you use a 4L60E trans, no need to worry about lockup signal since the PCM will control the trans.  If you use the Corvette trans, you will need to convert the engine to cable throttle and then figure out how to connect a TV cable to it in such a way that you don't burn up the trans, even before figuring in lockup.

That's why, IMO, using a 4L60E trans is the easy button.  The adaptor looks expensive until you see all the other stuff you don't have to buy.  I am greatly assuming that it will allow you to use the Corvette tailhousing so you can use the trans-diff member.

 

Part of me wonders what it would take to put the 4L60E internals in a 700-R4 case, too.  Probably a lot.

QuasiMofo (John Brown)
QuasiMofo (John Brown) GRM+ Memberand MegaDork
5/3/23 7:17 a.m.

I'm going to roll with the 700r4 currently, when it goes away I will likely use a 1996 style 4L60e from a Corvette or adapt to 4L80E with a stand alone shift controller, but even  that would still need an external lockup solution. 

I cannot believe that someone hasn't packaged a little processor that reads vacuum and 4th gear activation then creates a signal on with delay. Maybe it can be done?

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
5/3/23 9:18 a.m.

In reply to QuasiMofo (John Brown) :

It has definitely been done.

Peabody
Peabody MegaDork
5/3/23 9:44 a.m.
Pete Gossett said:

I do agree that the C4 styling has aged better than the C5

I can't believe I just read that

yupididit
yupididit GRM+ Memberand UltimaDork
5/3/23 10:02 a.m.

So a c5 drivetrain will not drop in a later c4?

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