Mopar92
Well-Known Member
There was a Demon at Carlisle this year that had a Crown Vic cradle in his. Didn't look butchered. Got coilovers, sway bar and everything to work. Pretty nice looking donor idea.
Lexus SC300/SC400 front suspension
- Thread starter Greg55_99
- Start date
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Furious65
C-body Guy
Check out the screen shot from the '72 Plymouth service manual I attached. I, too, have never heard of there being a difference between 2dr and 4dr A-body cars just the disc vs drum width. I'm just assuming that the manual is incorrect.
Looking at how the factory Lexus coil springs and shocks mount, it looks to me it would take some some extensive surgery to the inner fenders plus would still require something like HDK's shock hoop supports for added strength. The shock/coilover setup in post #7 is an aftermarket setup and would definitely add to the cost but probably would be easier (less cutting of inner fender) to fit in an A-body.
Outside to outside measurement doesn't mean a whole lot as changing rims can change that spec. These are high offset wheel type front ends unlike our factory zero offset front ends. What is most important is track width so that we don't screw up the scrub radius too much from what it was designed for. The stock track width on the '03-'04 CV front is 63.4". Compared to Dukeboys supplied spec of 59.2" ('72 manual says 59.7"), that's a 4.2" (3.7") difference. That 4.2" (3.7") would need to be removed from the cradle and rack. That's where the CV front end gets out of the DIY aspect for most as you need to be able to weld aluminum and properly shorten the internal shaft of the rack.
I don't blame you for looking for more affordable DIY options. I'm the same way. It doesn't really help us on our A's but I think the stock CV front would be close to perfect for a C-body. That's what got me researching it in the first place, as an upgrade for my '65 Sport Fury. However, a lot of people will just shoot down our out of the box type thinking on such things. Yes, I would jump at one of Denny's setups (the best out there IMO) if I had the cash but it just isn't going to happen with my budget. So, people like us keep looking!
The track width difference isn't a 2-door to 4-door thing. It's a '67-'72 drums or KH disks compared to '73+ disks thing. From a factory TSB...
A few other thoughts. Our A-body's are NOT best served by zero offset front rims. Even most of the factory rims have a +6 offset, not zero. If you want much wider than factory width tires, well, the 18x9's on my Duster are +27 and that's with the '73+ width. So, adding a few inches is a big deal, if you go past +50 for a wheel offset you're going to have a hard time finding rims. And what's the point of adding an allegedly better handling suspension if you can't match it up with a set of giant front tires to actually keep the whole mess on the ground?
I'm not against hot rodding or anything, I've done my share. But just because the SC400 is a good set up doesn't mean it will still work well when it's been modified to fit an A-body, or that an A-body will work well with SC400 suspension. There's a whole lot of engineering that went into both, and if you want to put them together and still have it work well it will take a whole lot more.
Right? Like the custom engine mounts, steering shaft, oil pan, headers and chassis reinforcements will be easier to deal with than the bolt pattern.
A few other thoughts. Our A-body's are NOT best served by zero offset front rims. Even most of the factory rims have a +6 offset, not zero. If you want much wider than factory width tires, well, the 18x9's on my Duster are +27 and that's with the '73+ width. So, adding a few inches is a big deal, if you go past +50 for a wheel offset you're going to have a hard time finding rims. And what's the point of adding an allegedly better handling suspension if you can't match it up with a set of giant front tires to actually keep the whole mess on the ground?
I'm not against hot rodding or anything, I've done my share. But just because the SC400 is a good set up doesn't mean it will still work well when it's been modified to fit an A-body, or that an A-body will work well with SC400 suspension. There's a whole lot of engineering that went into both, and if you want to put them together and still have it work well it will take a whole lot more.
Right? Like the custom engine mounts, steering shaft, oil pan, headers and chassis reinforcements will be easier to deal with than the bolt pattern.
Furious65
C-body Guy
You're probably correct. I was just pointing out what the 1972 Plymouth service manual stated. It doesn't point out a difference between disc or drums just 2 vs 4 door. Go figure.
Our A-body's may not be a true zero offset but, for most practical purposes, they are considered as such. I know that doesn't mean squat in a technical discussion but it's just how they have been looked at over the decades and rims have been used accordingly. I know as long as you don't deviate too much from the factory track width with the rim/tire combo it shouldn't affect the scrub radius too drastically and the negative handling effects that come with it.
Finding rims to work is not an issue for the Lexus or CV front. There are literally a few hundred styles/sizes available to fit. The real issue is getting a rim that will also work on the rear that matches the front high offset without using a longer rear axle, spacers, custom built rims, or some combination of the three. Of course, going with off the shelf classically styled muscle car rims is practically not an option.
Possibly correct but no one will ever know unless someone tries it. It could be great or it could suck. I know there are a lot of things that need to be considered such as the ride height, track width, the angle (if any) of how the cradle was mounted in it's OEM vehicle, possible strengthening/clearancing of the chassis, engine mounts, connecting the factory column to the Lexus or CV front end, etc., etc. However, that's what hot rodding has been about since it started, trial an error. Seems like most people nowadays just wants to buy bolt-ons and doesn't want to, or doesn't have the skills, to research things and fabricate/modify things themselves. <sigh>
There's nothing unique about the 4 door suspension. They had the same brake options as the 2 door cars. Sure, it's the track width that's listed and that depends on the tires too, but again, there weren't any unique tire or wheel options available on the 4 doors that you couldn't get on a 2 door. Maybe they spec'd the base option which had a different package. As far as the manual goes, it may also be worth noting that you're not looking at an original 1972 manual. That's a PDF, so depending on how it was created it may be different than the original. This is a scan from the '71 dealer book, notice how it shows 2 and 4 doors with the same track. Of course, it also show's the Demon's with a .1" wider track. That may have been a difference in the base option rims or tires. At any rate, any track width difference comes from the brake or wheel options, the chassis and suspension are the same.
Here's the problem. It's not about finding rims to fit the Lexus front suspension. You're right, there are tons. It's about finding rims that fit the Lexus suspension that ALSO fit inside the fenders on an A-body. I measured the front end of my car as in the first few pictures, outside edge of the tire to outside edge. Now, that's a really rough measurement, but it's something. I got 69", just like for the SC400 front end. But, here's the thing, my car has no extra room to the outside. So, whatever that SC400 has on it, that's as wide as you can go to the outside. If it's got +50 offset rims (like the factory rims for that car), you're not going to be able to do much to add tire width because anything extra you add has to be on the inside, so more offset. I'm not sure what tires are pictured, they look like they could be fairly stock which would mean 225's. If that's the case, and they're 225's with a +50 offset, even going to a 245 would mean a +70 offset rim. Not going to find a lot of those. The math says about the same. The track width of the 73+ cars is 59.15", plus the rim offset (+6) because the track width includes the rim offset, so the hub to hub should be ~59.6". The SC400 track width is 59.9", which is almost the same, but that's with a +50mm offset factory rim. So, the hub to hub is more like 63.8". That's a 2.1" difference on each side, so, 53.8mm wider on each side than a 73+ set up. On my Duster I run 18x9's with 275's and an effective offset of +27. That means to run the same wheels and tires with an SC400 front suspension my rims would need to have an offset of +80.8. Not going to find those either.
And the A-bodies already have the front to rear offset mismatch straight from the factory if you want to run wide tires. That's why I have a 68-70 B body 8 3/4 in my Duster. If I ran a A-body 8 3/4 with BBP axles my rear offset would need to be +9mm with the 18x10's and 295's that I run, compared to the +27mm offset I have up front. As it is with the B body 8 3/4, my rims are +38 in the back and +35 in the front (the +27 comes from a 3mm spacer and Dr. Diff's 13" rotors that add 5mm compared to the 73+ disks). And really I could use +35 front and rear with the 3mm spacer up front.
Hey if someone wants to try it I'd like to see it. But there are a TON of potential issues. And honestly, when you're all done, you may not have a car than handles any better than one with a well tuned torsion bar suspension even if everything works great. Because really, a well tuned torsion bar suspension is no slouch. The current coil over conversions aren't demonstrably better. The Hotchkis Taxi can lap at TireRack's test track faster than the 2012 3-series beemers they use for testing. That's a ton of work to undertake on a "maybe", even if you have all the skills. I do, I have both the skills and equipment to make that happen if I wanted to, and let me tell you I have zero desire to do it. If you spent a fraction of the time and effort needed to complete that swap you could have a very well handling torsion bar suspension car.
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I've been considering the b body 8.75 for the same reason, did you run it stock or cut it some?
Furious65
C-body Guy
Not disagreeing with you at all. I know there is no real difference between 2 or 4dr. I just thought it was odd that the .pdf manual I have listed it as such and was wondering if it was a known mistake in it. No biggie.
I know you know your stuff when it comes to making an A-body handle. I've probably read every post you've made covering the topic. The thing I think you're missing is that not everyone is after max performance handling on our A's. Some of us would just like an updated, lighter, more responsive front end that we can buy replacement parts right from our local auto parts store for our weekend cruiser/daily driver. I don't need AutoX performance and wide 275's all the way around nor the ride quality that comes along with it.
With a Lexus/CV type front we would gain a disc brake conversion, power rack and pinion steering, and potentially some weight savings. Other potential pluses are easier starter access and maybe more room for headers/exhaust.
I think it's just like anything else when it comes to our cars, what do you want your car to do, what is your budget, and we're all just a bit different!
Furious65
C-body Guy
Yeah, I snagged that one as well!
Right? Like the custom engine mounts, steering shaft, oil pan, headers and chassis reinforcements will be easier to deal with than the bolt pattern.
I appreciate the response and observations you've posted. I don't agree with some of it, but, I think you've hit on many technical details that would help or could hinder a swap such as this. I have one major objection however and it's your use of the word "custom". A minor thing, but to me when you use the word "custom" it means "this is going to cost you major money". Like engine mounts, oil pans, steering shafts and headers. I prefer to use the term "modify". If I "modify" these things that I have, then I don't spend major money. Make a difference, yes? I'll give you an example. Some years ago on a junkyard crawl, I came across a Datsun 240Z car with a Mopar Small Block installed. I had my camera with me so I took a few pics of things that interested me about it. Particularly, how the engine was mounted to the subframe. To my untrained eye, it looked like the "modifier" cut and shut a pair of Small Block truck brackets, welded them back together and bolted them to Datsun biscuits. The whole deal didn't look like it cost more than a few bucks and an hour of time. My point is, a hot rodder WILL find a way... CHEAP (Inexpensively...).
Engine mounts don't work? Modify existing mounts yourself.
Oil pan doesn't fit, find one that does. Center sump, front sump, rear sump.
Steering shaft won't work? Modify with a coupling.
Reinforce chassis? OK, a good welder and plate steel comes in handy.
That's "hot roddin'".
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No, I haven't forgotten this. But I did locate a gent (Chris) on the internet that IS doing this swap in a T-bird. He sent me some info and pics:
"My Thunderbird is unit-body, and the lower frame rails curve upward where the front suspension mounts to, so I had to weld in pads for the crossmember to rest on. The aluminum crossmember's mounting bolt pattern is 31" wide, 6 1/4" long, and centers up well on most frame rail widths. You may not have as much of a problem with a Buick chassis. I also fabricated custom rear mounts for the lower control arms, and will weld in a second crossmember once the engine is in and I can measure clearances. The Buick engine should play well with the SC300 crossmember, as the engine is rear sump, and the steering rack is ahead of the axle. Best parts are, this is the same IFS as the Toyota Supra, so performance parts are available, and brakes from the '95+ Lexus LS400 are also a direct swap. So you can choose between massive brakes, or slightly more massive brakes! I'm using the LS400 brakes, the 4 piston calipers are aluminum. The Supra twin turbo calipers are only a little larger, and iron. Neither fit behind 15" wheels. Ford/Toyota bolt pattern, 5 on 114.3mm (4-1/2"). I'm running 3/4" spacers to match the Toyota wheel offset AND the Thunderbird track width, 59.8" SC300, mine 62". I also made my own 'coilovers' using some KYB gas-a-just shocks I got a great deal on, and some 12" 500 pound rate springs from Speedway Motors, and made my own strut tops to adapt them to my stock shock towers. If I later want to upgrade to Bilsteins, there's a thread in the Supra forums on how to adapt them to the Supra/SC300. Just Google."
Now THAT'S Hot Roddin'! I hope he'll swing by.
Greg
"My Thunderbird is unit-body, and the lower frame rails curve upward where the front suspension mounts to, so I had to weld in pads for the crossmember to rest on. The aluminum crossmember's mounting bolt pattern is 31" wide, 6 1/4" long, and centers up well on most frame rail widths. You may not have as much of a problem with a Buick chassis. I also fabricated custom rear mounts for the lower control arms, and will weld in a second crossmember once the engine is in and I can measure clearances. The Buick engine should play well with the SC300 crossmember, as the engine is rear sump, and the steering rack is ahead of the axle. Best parts are, this is the same IFS as the Toyota Supra, so performance parts are available, and brakes from the '95+ Lexus LS400 are also a direct swap. So you can choose between massive brakes, or slightly more massive brakes! I'm using the LS400 brakes, the 4 piston calipers are aluminum. The Supra twin turbo calipers are only a little larger, and iron. Neither fit behind 15" wheels. Ford/Toyota bolt pattern, 5 on 114.3mm (4-1/2"). I'm running 3/4" spacers to match the Toyota wheel offset AND the Thunderbird track width, 59.8" SC300, mine 62". I also made my own 'coilovers' using some KYB gas-a-just shocks I got a great deal on, and some 12" 500 pound rate springs from Speedway Motors, and made my own strut tops to adapt them to my stock shock towers. If I later want to upgrade to Bilsteins, there's a thread in the Supra forums on how to adapt them to the Supra/SC300. Just Google."
Now THAT'S Hot Roddin'! I hope he'll swing by.
Greg
This is a really interesting thread. I am thinking I like the SC400 maybe better than the CV frontend. For a guy with more time than money this might be the ticket for a lighter weight drag car frontend.
Tom
Tom
MopaR&D
Nerd Member
I'm kind of siding with 72bluNblu here just for the fact there are a lot of options for making our factory A-body torsion bar front ends work a lot better, IMO it's kind of a toss-up. What I REALLY think this is a Godsend for are the F/M/J-body cars. Looking at that last pic from @Greg55_99 it reminded me of my 1988 Chrysler Fifth Avenue I had for a while. Totally self-contained front end on those cars and the factory setup SUCKS, not worth spending any money on which hardly anyone makes parts for anyway besides Firm Feel.
I'd love to get a boattail 2-door Dodge Diplomat and put one of those Lexus front ends in it with whatever built SBM or even G3 Hemi, sleeper to the MAX lol
I'd love to get a boattail 2-door Dodge Diplomat and put one of those Lexus front ends in it with whatever built SBM or even G3 Hemi, sleeper to the MAX lol
That narrow CV crossmember is fabricated steel and is $795. If your going that route you might as well just build your own. My idea for wanting to using a Lexus clip is to gain width inside the engine compartment and shedding weight at the same time. After some research using a 92-98 SC300 will give you 10.8" brake rotors and the 92-00 SC400 99 SC300 will give you 11.6" rotors. If you still want more the 95 LS 400 brakes are a direct bolt on with 12.4" rotors and a very nice aluminum 4-piston caliper. Then if your all out road racing the even larger brakes from a Toyota Supra also bolt on. More options for the guy that likes to play around with projects.
Tom
Tom
This has always been my view. If you've got a nice A body sitting in your garage you want to upgrade and at the same time Little Sparky needs braces... Guess where that 5 grand is going to go... Now, I can slide maybe two or three hundred past my banker by telling her I'm trading or selling old stuff, but 5 gees... no way. But then... that Hot Roddin'...
Greg
Greg
Here's some really nice photos of the front clip within this ad for a $1250 manual steering rack for a Toyota Supra. Which is what a Lexus SC is since Toyota also owns Lexus. Nice clean looking light weight front suspension and I can't wait to get my hands on one.
MKIV Supra Manual Steering Rack (power steering delete)
Tom
MKIV Supra Manual Steering Rack (power steering delete)
Tom
Even shortened the crown vic front end is over 62” hub to hub though, which means like an extra 1.25” of backspace will be needed compared to a 73+ Mopar disk set up. With narrower rims that might not be a problem, but the diameter and brake clearance can be a problem. Most 15” rims won’t clear the brakes with much more than 5” of backspace, which means 15x7’s probably wouldn't work, you’d need at least 5.5” of backspace to on a 15x7 just to run a 225/60/15 on the narrowed CV front end. Now, you're talking Ford brakes and not Mopar so that backspace clearance wouldn't be the same, but 5.5" is a lot for a 15" rim. So you'd probably have to use 17 or 18" wheels, and those would need an offset starting around +40 for 225's and going up from there.
What is the actual hub to hub width on the SC400 spindles? Working backward from the track width using the stock wheel specs I came up with ~63.8” earlier. If that’s accurate, the Lexus front end would require ridiculous amounts of backspace. As in, add 2.1" to what you would normally run on a 73+ Mopar set up. You'd need wheels with a +60 offset just to run 225's, and the 275's I run would need a +80 offset. You're not going to find that.
I totally respect the ingenuity, but if those hub to hub numbers are right neither one of those would be a very useful front end for an A-body. If you can't put decent size tires on it there isn't much point spending that kind of time on the suspension upgrade.
pishta
I know I'm right....
interesting...I own both an SC400 and a 65 A. Word on those Upper and lower control arms...no serviceable ball joints and nothing new is cheap on a Lexus/Supra. And they do handle like a ****..... if you need an SC measurement I can oblige.
I would interested to know what size tires your running on your SC400 and what the measurement from the bottom of the frame rail is near the engine cradle attachment point to the ground is?
Thanks,
Tom
Thanks,
Tom
I'd love to see a hub to hub width measurement on the front end. If it's close to what the math says it is the project seems like a non-starter to me. What you can run for tires on an SC400 and what will actually fit on an A-body will be entirely different things...
Rambler American with a 56" track width on an SC300 chassis:
"Uncle Ben" - Rambler American Wagon / Lexus SC300 Body Swap-Page 12| Builds and Project Cars forum |
Big fun.
Greg
"Uncle Ben" - Rambler American Wagon / Lexus SC300 Body Swap-Page 12| Builds and Project Cars forum |
Big fun.
Greg
pishta
I know I'm right....
205/65R16 tires, 67" inch track tire edge to edge with a 2" tire lip to hub distance so hub to hub would be about ~63" and most everything under that car is 5" off the deck. Its very flat under there. So the 63.8 sounds incredibly close.
Here's what measurement I was after since the measurement in the image was without a drive train. I wonder what it is on a complete car? This will help me see where the frame needs to be at normal ride height when grafting into a different body.
Thanks Tom
Thanks Tom
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