Noob in over his head: FWD->RWD conversion

Hello GRM. You may remember me from my 96 Century build thread. Flush with my minor success of transplanting a 60 degree V6 into my 60 degree V6-powered car, I've gone off the deep end. I am currently in the very preliminary theory and planning stages of a front to rear drive conversion.

The car in question:

If it looks familiar, that's because it is! This is a 1993 Buick Century Custom wagon (not unlike my '96) I picked up off of craigslist back in August 2015 for essentially scrap value ($200). I didn't really know what I wanted to do with it at the time, aside from parts car status, but in the intervening year and a half, a terrible plan began forming within me. A plan of a stripped out, clapped out troll machine, smoking the too-narrow rear tires when it should be doing that to the front.

Here's what I have so far. I want to make this car rear wheel drive, with some variety of LS (probably a mildly cammed 4.8L truck engine) and a 4L60E automatic. My brother is willing to donate the rear axle from his 2001 Z28 (3.42 posi, though I will probably have it rebuilt to 3.23) once he gets a hold of a Moser 12 bolt for himself. After looking at the Century's torsion beam and the Camaro's live axle, it seems like I could probably swap over the Century's shock and spring mounting points to the Camaro axle to attempt to keep the rear suspension geometry, such as it is, in the stock location.

Lots of cutting of the body will be necessary to make room for the transmission and driveshaft. I am not worried about this, because as I said, I paid almost nothing for this car, and it was a rolling dumpster fire in the first place. I am unconcerned with possibly irrevocably ruining this chassis. If I do, oh well, off to the recycler, and hopefully some lessons learned about what not to do.

A fuel cell is in the cards, since the stock fuel tank wants to occupy the same space as a theoretical driveshaft. Not sure on what size to use, but a 15 gallon keeps jumping out at me on ebay for not too big of a price. Probably mounted inside the rear of the cabin where kids would put their feet when seated in the third seat. In a cage. Or something.

I am not planning to make this look stock, like I did to my '96. This will have no interior aside from a driver's seat and some gauges somewhere, and some of the stock carpet to keep any stray pebbles tracked in from rattling on the bare metal floor.

Where it gets a little fuzzy is up front. I think the Century's stock struts and knuckles may be okay to reuse, since I don't plan on this being anything other than a straight line vehicle. I'm not really sure yet what to do about the steering rack and how to modify the subframe to allow the transmission to mount up to the body. F-body seems like the way to go, maybe even with an F-body column. After that, I don't know how I would mate the rack to the knuckles and keep some semblance of stability.

Any suggestions would be appreciated!

EDIT: To pre-empt anyone who might say it simply can't be done:

That is a Cutlass Ciera, the sister car to my Century, doing a wheel stand. I haven't found any build information yet, but I'm told it is a stock body, not a silhouette car (that is, a tube chassis).

It can be done. Anything can be made to fit if you have a saw and a welder!

I would get the engine and trans and mock them up in the car before worrying about where the steering is going.

You may not need to move much around.

I would fab up the trans mounts. I am thinking there is no way to use stock ones from any vehicle.

You'll end up cutting and massaging part of the firewall and tunnel I'm sure. As for the front suspension, make sure the front wheel bearings don't need an axle stub installed to stay together, if they do you'll need to remove the cup from the fwd axle and install it in the knuckle. As for the rear, it looks like it building a truck arm would be the easier route? Other than that, anything is possible with a cutoff wheel and a welder.

Just repeat this to yourself any time you question your ability: "im a redneck with a rabbits foot and no fear of failure"

Its a very liberating mindset.

wvumtnbkr wrote: It can be done. Anything can be made to fit if you have a saw and a welder! I would get the engine and trans and mock them up in the car before worrying about where the steering is going. You may not need to move much around. I would fab up the trans mounts. I am thinking there is no way to use stock ones from any vehicle.

I will definitely have to fabricate all the engine and transmission mounts. My brother with the Z28 is a welder and has offered his fabrication services as needed. Mockup will be waiting for some time, since the only parts I have so far are the aforementioned Z28's stock exhaust manifolds. (He installed headers.)

minivan_racer wrote: As for the front suspension, make sure the front wheel bearings don't need an axle stub installed to stay together, if they do you'll need to remove the cup from the fwd axle and install it in the knuckle.

The hub is bolted to the knuckle and is a sealed unit. So far I don't see a need to have anything in it to hold it together. Time will tell.

Dusterbd13 wrote: Just repeat this to yourself any time you question your ability: "im a redneck with a rabbits foot and no fear of failure" Its a very liberating mindset.

Love this.

You should still "cage" the hub bearings as they could come apart or develop play over time.

minivan_racer wrote: The hub is bolted to the knuckle and is a sealed unit. So far I don't see a need to have anything in it to hold it together. Time will re I love this

Dusterbd13 wrote: Just repeat this to yourself any time you question your ability: "im a redneck with a rabbits foot and no fear of failure" Its a very liberating mindset.

Love this.

Would S-10 or F-body parts help turn the existing V6 that you have in the car now to a north/south setup? Not as exciting but probably cheaper and packaging would probably be easier. By my math there's probably an oilpan that needs to be changed or modified and at least one exhaust manifold.

I could see a lot of the floor around the firewall needing work to fit around whatever transmission you go with. Also the previously mentioned trans mount. Rear suspension may not be that bad but understand that the forces traveling through it from the rear axle when accelerating weren't really designed into the car. Probably need to do a subframe / floor connector to create a good load path from wherever the rear suspension pickup points are.

Far from impossible but not a weekend project either.

Dusterbd13 wrote: Just repeat this to yourself any time you question your ability: "im a redneck with a rabbits foot and no fear of failure" Its a very liberating mindset.

I just found my new slogan.

pres589 wrote: Would S-10 or F-body parts help turn the existing V6 that you have in the car now to a north/south setup? Not as exciting but probably cheaper and packaging would probably be easier. By my math there's probably an oilpan that needs to be changed or modified and at least one exhaust manifold. I could see a lot of the floor around the firewall needing work to fit around whatever transmission you go with. Also the previously mentioned trans mount. Rear suspension may not be that bad but understand that the forces traveling through it from the rear axle when accelerating weren't really designed into the car. Probably need to do a subframe / floor connector to create a good load path from wherever the rear suspension pickup points are. Far from impossible but not a weekend project either.

My car has a 3.3L variant of the Buick V6, so it's not compatible with anything that was put into an S10, but it is related to the 3.8L used in the 96-02 F-body. I'm hesitant to commit to the stock engine though, since it would be pretty much the same amount of work to change the orientation as it would to use a V8. My car also does not have the same subframe style as the S trucks or F cars.

A quick googling comes up with some dimensions of a fully-dressed LS1/6 from what looks like a C5 as being about 29" from flywheel to water pump, 27-29" from intake to oil pan depending on pan depth, and 30" from AC compressor to alternator. Fairly compact and cubic. Really quick and dirty measuring of the engine bay says it should fit fairly well, with maybe the brake booster and hood clearance being an issue if I can't get the engine to sit low. ZZPerformance sells subframe spacers that are 1/4" thick, but I don't know how I feel about stacking a whole bunch of those up. Might have to "massage" the hood a bit. I'm not sure what to do about the booster. I may also have to use a "front sump" oil pan, I think for a GTO, to make room for a steering rack. Maybe I'm wrong though. I don't know yet.

In my other interwebs travels I found Smith Performance. According to their site, they've been doing this very conversion for 30 years, starting with a Cutlass Ciera back in 1987. Their site is critically short on details, so I sent them an e-mail, assuming they're still in business.

Would it not be easier to take the whole front subassembly from the late Bonneville ssei v8, or grand prix gxp and just make it m/ r?

mndsm wrote: Would it not be easier to take the whole front subassembly from the late Bonneville ssei v8, or grand prix gxp and just make it m/ r?

LS4 definitely would be "easier"! I'm not after easy though. If you mean transversely mounted in the back, I have entertained that idea as well, but that presents a different set of challenges. It also introduces a known weak link in the 4T65 transmission attached to the LS4. They break with alarming regularity even behind stock LS4s.

Uhm, those subframe spacers would do what for you?

You're going to need a welder. Or a friend that welds. A torch would be good too but a welder is all but required. If the hood doesn't clear this thing, I would get down with a rivet on cowl hood scoop, and keep moving forward.

My two cents.

pres589 wrote: Uhm, those subframe spacers would do what for you? You're going to need a welder. Or a friend that welds. A torch would be good too but a welder is all but required. If the hood doesn't clear this thing, I would get down with a rivet on cowl hood scoop, and keep moving forward. My two cents.

The subframe spacers would put that little bit of space between the top of the engine and the hood by raising the body relative to the subframe, as I understand it. It looks like they're supposed to go in between the corners of the subframe and the body. It was just one idea I'm throwing at the wall to see what sticks. I kinda like the Roadkill-style scoop though. Might even make for a halfway decent ram air intake!

As I said earlier, my brother works for an architectural metals shop, doing both fabrication and installation of fairly high dollar pieces. Cutting the body open and welding it back together should be nothing for him. He's on board, at least for now. It's gonna be quite some time before I can even think about tearing into this thing.

Build engine mounts so this sort of thing isn't needed.

You're overthinking the rear end. It'll take some searching but there is a rear axle that will bolt into your car with no mods.

The Pontiac 6000 STE was an all-wheel-drive A body. That rear end would do the job for you.

Your 3300 will bolt up to any 2.5, 2.8, or 3.4 S10 transmission or any 3rd or fourth gen v-6 Camaro. You may also use a Dodge Dakota bellhousing to mount up an MK2 Supra 5 speed.

I'm not sure why you would even take this path!

trucke wrote: I'm not sure why you would even take this path!

Why not? Even if I fail, it will be a learning experience.

I keep getting this exact same response when I talk about doing this project, whether online or off. "Why?" Because I want to. I want to have a unique car, just like my other wagon with the LX9. What, is it because it's a Buick station wagon? Would it be more palatable if it were a Grand Prix? I see plenty of folks are on board with the Dodge Shadow being converted to RWD.

If all you're going to do is post "lol but y tho" then don't bother. It's not constructive, and it does nothing but add useless white noise to the conversation.

Did not mean to offend, but I guess I did.

Just seems like there are 'cooler' options for mods you are envisioning. You goals mean you absolutely fit in with this crowd. You have way more ambition than I have. You are right that you will learn a ton of useful skills. Go for it!

As a GM guy I'm used to hearing "Why?" especially from this crowd.

I built a 13 second Saturn wagon. "why?" I built a low 16 second U-van. "again why?" I autocrossed an grand prix "why would you do that?"

Because I'm interesting.

trucke wrote: Did not mean to offend, but I guess I did. Just seems like there are 'cooler' options for mods you are envisioning. You goals mean you absolutely fit in with this crowd. You have way more ambition than I have. You are right that you will learn a ton of useful skills. Go for it!

No worries mate. Sorry if it seemed like I was singling you out. Like I said, lots of people keep saying the same thing, and it has gotten a bit frustrating and annoying.

AClockworkGarage wrote: As a GM guy I'm used to hearing "Why?" especially from this crowd. I built a 13 second Saturn wagon. "why?" I built a low 16 second U-van. "again why?" I autocrossed an grand prix "why would you do that?" Because I'm interesting.

I am very interested in hearing about these things.

AClockworkGarage wrote: Your 3300 will bolt up to any 2.5, 2.8, or 3.4 S10 transmission or any 3rd or fourth gen v-6 Camaro. You may also use a Dodge Dakota bellhousing to mount up an MK2 Supra 5 speed.

If I remember correctly you need the bellhousing from a AX15 out of a cherokee with the GM 2.8. The only engines the dakota had with a AX15 are the 2.5 Chrysler and 2.5 AMC, and I'm pretty sure the 2.5 AMC shares its pattern with the 4.0 not the GM v6.

minivan_racer wrote:

AClockworkGarage wrote: Your 3300 will bolt up to any 2.5, 2.8, or 3.4 S10 transmission or any 3rd or fourth gen v-6 Camaro. You may also use a Dodge Dakota bellhousing to mount up an MK2 Supra 5 speed.

If I remember correctly you need the bellhousing from a AX15 out of a cherokee with the GM 2.8. The only engines the dakota had with a AX15 are the 2.5 Chrysler and 2.5 AMC, and I'm pretty sure the 2.5 AMC shares its pattern with the 4.0 not the GM v6.

I didn't know the ax15 came behind the 2.8. I thought the ax4/5 were possible with the 2.8 but the ax15 was 4.0 only.

LV, having finished reading your other effort, move this to the 'build' column, pull the trigger with a LHU/5spd, the 'maro rear end and let the rough side drag bro. DO IT NOW!!! Berk all the naysayers and if you can put up with him, bring pop on board !

Iam well into a similar conversion on a sebring. I appluad your effort. Have you sorted out the rack issues yet? I think I have mine figured out if ya need input. Should have pics on my build page in a week or 2...maybe 3..lol.. good luck