Posted this on a Firebird forum but wanted to get y'all's take on it (and provide some entertainment along the way). Let me know what y'all think if I am crazy or just stupid.

I have started my engine swap on my 68 Firebird due to the freeze plugs rotting out in the back of the block.

Current specs:
350 2 bbl
ST300
8.2" 2.56 rear posi

Trying to find a path that makes the most sense for me right now to get the car back on the road. Listed what I've come up with as far as options starting with most expensive to least expensive.

Option 1 - mucho expensive
6.0 LS
4l80E
New Driveshaft
New Ford 9" Rear End with 3.73's or 4.10's (built by Currie w disc brakes)
Add front disc brakes

Option 2 - still kind of expensive
6.0 LS
4l80E
New Driveshaft
Junkyard Rear End 8.5" with 3.73's or 4.10's
Add 4 wheel disc brakes

Option 3 - cheapo/quickest option (i think)
6.0 LS
rebuilt TH350
Factory driveshaft
factory 2.56 rear end
Add 4 wheel disc brakes

What is your budget and use case for the car?

If it's not got a very valuable VIN and you plan to drive it, restomod is the way to go. Drum brakes and lack of overdrive suck.

The LS is a great restomod engine, but avoid the 4.10 rear. Going from 2.56 to a 4.10 will make it feel like a dump truck.

How strong is that factory 8.2"? Can it support 400+ lb-ft of torque reliably?

For a cruiser that you're wanting to get back on the road, Option 3 is probably plenty, and you can always reseal and re-gear the 8.2". If it didn't have posi, I'd use that as a big reason to replace it.

Flaith said:

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How strong is that factory 8.2"? Can it support 400+ lb-ft of torque reliably?

For a cruiser that you're wanting to get back on the road, Option 3 is probably plenty, and you can always reseal and re-gear the 8.2". If it didn't have posi, I'd use that as a big reason to replace it.

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It should be able to, they had them behind 455 motors in 67-72 until Gm switched to the corporate 10 bolt, 12 bolt, etc.

Unfortunately the 8.2" was built in 3 flavors depending on the gears, one size could take up to a 2.78 (mine), the next one up to a 3.5 i believe, then the last one was i think up to 4.10.

Hindsight is always 20/20, I added the posi last year so i'd prefer to save it for now.

lb3 said:

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What is your budget and use case for the car?

If it's not got a very valuable VIN and you plan to drive it, restomod is the way to go. Drum brakes and lack of overdrive suck.

The LS is a great restomod engine, but avoid the 4.10 rear. Going from 2.56 to a 4.10 will make it feel like a dump truck.

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Cruiser and make lots of noise haha

It's almost as generic as it gets for a 68 Firebird. Standard 350 2 barrel carb (not HO) with 2 speed auto & open 2.56.

Are you planning to run a Holley terminator to control the engine and transmission? I would assume they could program for the ZF8, but I know there is off the shelf support for LS+4L80

Are you able to regear the 8.2? I don't expect you would break an axle if you don't have traction. If you're planning to haul ass with traction, GM 8.5 w/ good diff.

Agree with above that no 80e in 2025. ZF8 or just do a built 4l60e. Built 60e is probably cheaper, but I haven't looked at costs of zf8 swap.

Completely disagree with lb3 regarding 4.10 gearing, but gearing is ultimately up to the overall configuration. You should set everything (engine, trans, & tire) and then choose gearing. But I can say that if you were to pair a 80e with 2.56 gearing, a dump truck might beat you to the 60'.

Exactly what kind of noises you want to make and how much you're willing to tinker AFTER the swap will have an influence on my answer. Cheapest/easiest route is probably just dropping in a crate gen I. You could pair it with an OD transmission and use a standalone controller for trans.

I've been researching ZF for my LSA yukon. My parts list is ~$3k for the transmission, adapter kits, and aftermarket trans TCM. Terminator X Max doesn't support the ZF. Most any ZF8 out of a Ram or Charger works great.

A used facebook 4l80 is $500-1200, another $1200 for a decent torque converter, and then a $100-300 harness adapter if you're running a 0411 or P59 style ECM or a Terminator X Max if going aftermarket. End of day, I think it's close to a wash or the ZF may be slightly more expensive.

I think an extra $500-1k is well worth the better driving experience, much newer tech, 4 extra gears, and better power/fuel efficiency.

A little off topic but I may be interested in your 2 barrel carb if you still have it and willing to part with it.

Back on topic, I don't know where you're thinking about sourcing your LS, but if it were mine (knowing how easy it is to do engine removal on first gen f-body cars) I'd find a good deal on a junkyard LS, drive it until it dies (or you have desire/budget) and do a rebuild.

For transmission I'd also try to find a good ZF as those things are pretty easy to work on, fairly ubiquitous (parts) in a lot of applications, and pretty rock solid.

As someone else mentioned, first gen F-bodys aren't really engineered to handle an overload of torque and even with frame stiffeners/subframe-to-frame-rail-connectors, you'll be surprised how much you can stress factory seams. Just keep that in mind. It's even more so if your car is a convertible.

If you're going all out, you can always go for that Ford 9 inch rear end.

While not the same endeavor, for entertainment value Paul Cox stuffed a supercharged 408 in a '67 firebird.

I'd be happy to let you have the carb once I get through this build unless you need it urgently.

I do not think it's factory if that matters to you. Once I got the air cleaner off I noticed it had a reman stamp on it, i think its an Edelbrock.

Dead set on an automatic? Perfect candidate for a 5 or 6 speed manual swap.

Ag for Life said:

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Dead set on an automatic? Perfect candidate for a 5 or 6 speed manual swap.

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Pretty much, I've already got a manual 2005 Wrangler LJ that scratches the itch.

Status update:

- Lq9 to be delivered tomorrow
- transmission crossmember, speedo cable, and linkage removed
- driveshaft removed
- radiator & fan removed

Need to drop transmission down and re position the jack to get ready for engine removal. The front of the car is currently on jack stands but I may need to drop it down as i pull the motor, hence re positioning the jack. Also still need to unbolt the motor mounts.

Things left to figure out:

- engine harness
- eliminate unneeded existing wiring
- order lots of parts
- decide if i want to swap out the rear end now or later
- order transmission from builder
- probably a lot of other things i'm forgetting

Apparently I have no idea how to do this. Tried using Google Drive but that didn't work.

Call Howell EFI. I've used them for almost 30 years now for my efi harnesses and computers. They can hook you up with what will make your engine run.

You have a big project on your hands, but if you tackle one thing at a time, you'll get through it.

If this thing is never running slicks, and the 6.0L LS motor stays relatively stock (just some bolt ons) you shouldn't need a beefy rear end setup.

Nice! Following!

Nice! Are you planning on running an electric fuel pump? I can't recall either if the '68 350 had the return line but I think it didn't?

The LS 6.0L gets me excited! No bump stick before install?

Quote:

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Still need to decide on a DBW or DBC,

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What are your considerations on this decision?

CPjr & I ended up doing DBW because we figured that it wouldn't make a difference unless we were trying to race or adding some real performance enhancers. I'll admit that now, years later, I sometimes dream of what a twin turbo setup would look like or what it would take - then come back to reality and realize that even though it is built - we still have a 4L60. The project is old enough now that I get crazy notions about re-doing or changing it up... but honestly, it's just perfect as is for what it does.

After you decide that, and transmission options, what are you doing for a harness?

92_Ag said:

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Nice! Are you planning on running an electric fuel pump? I can't recall either if the '68 350 had the return line but I think it didn't?

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Yes I am.

And you are correct, it does not have a return line so my regulator/filter will be adjacent to the tank at the back of the car with a single line running to the motor.

I'll be running a 255 LPH Walbro fuel pump. I'll have to run power back there though.

Centerpole90 said:

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Quote:

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Still need to decide on a DBW or DBC,

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What are your considerations on this decision?

CPjr & I ended up doing DBW because we figured that it wouldn't make a difference unless we were trying to race or adding some real performance enhancers. I'll admit that now, years later, I sometimes dream of what a twin turbo setup would look like or what it would take - then come back to reality and realize that even though it is built - we still have a 4L60. The project is old enough now that I get crazy notions about re-doing or changing it up... but honestly, it's just perfect as is for what it does.

After you decide that, and transmission options, what are you doing for a harness?

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Silvy wants me to run DBC for the quicker throttle response but in my mind I think it'd be easier to set up a DBW. And the throttle body costs are near identical. And I won't have to buy a cable.

Aggie Dad 26 said:

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The LS 6.0L gets me excited! No bump stick before install?

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Uhhh not familiar w this term lol

What's this mean?

camshaft.

I vote for dbw

Corps_Ag12 said:

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92_Ag said:

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Nice! Are you planning on running an electric fuel pump? I can't recall either if the '68 350 had the return line but I think it didn't?

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Yes I am.

And you are correct, it does not have a return line so my regulator/filter will be adjacent to the tank at the back of the car with a single line running to the motor.

I'll be running a 255 LPH Walbro fuel pump. I'll have to run power back there though.

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What ECM are you running?

Racetronix had a pretty good fuel pump harness when I did my swap a few years ago. Nice heavy gauge wire. Was ~$50 when I bought the kit.

I ended up going with a Vaporworx PWM fuel management controller since I'm running a blower. I'd consider going that route now if you do plan for a power adder later.

https://www.vaporworx.com/shop/product/returnx-return-type-pwm-controller/

Corps_Ag12 said:

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Centerpole90 said:

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Quote:

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Still need to decide on a DBW or DBC,

---

What are your considerations on this decision?

CPjr & I ended up doing DBW because we figured that it wouldn't make a difference unless we were trying to race or adding some real performance enhancers. I'll admit that now, years later, I sometimes dream of what a twin turbo setup would look like or what it would take - then come back to reality and realize that even though it is built - we still have a 4L60. The project is old enough now that I get crazy notions about re-doing or changing it up... but honestly, it's just perfect as is for what it does.

After you decide that, and transmission options, what are you doing for a harness?

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Silvy wants me to run DBC for the quicker throttle response but in my mind I think it'd be easier to set up a DBW. And the throttle body costs are near identical. And I won't have to buy a cable.

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DBW is generally quicker throttle response since it can be configured to be as fast or slow as you want it. I have one of my cars set up where the ECM sees 1/4 throttle as 3/4 at the flick of a switch. Can't do that with DBC. You also get rid of the IAC and like you mentioned the throttle/cruise cables.

I did DBC on my LSA swap due to the simplicity. But if I was doing what you are, I'd go to the trouble of retrofitting a DBW pedal.

Bro can't keep track of all the messages lol

I'm 50/50 on DBC vs DBW. I do like the feel of DBC and it's more simple in a way. However, it seems easier to get a relatively large OE TB in DBW wire vs DBC.