1949 Cadillac Series 61 Build

[Qua-Hoon!]

Well I'm back. The car sickness has me again after a few years away. I found a 1949 Cadillac Series 61 for sale and picked it up for a reasonable price. Some people call this a Sedanette, but really that's for the previous body style. Either-way, it's the 2 door. It's still in shipping and should be here tomorrow but I thought I'd ask the questions now so I can research more on this rainy afternoon.

I've built a few cars in my garage before over the years, done frame off restorations, built engines, wiring, and a lot of welding panels for rust repair or improved gap fitment. I have this idea now that I think I'd like to build my own suspension for this car whether that be a front clip type of set up or just fully commit to the full frame. If I go full frame I know I need a frame table / jig. I've been trying to read any books I can get my hands on for this and have used the search function to find a couple main ones used. Honestly I know I can build jigs and level them, I'm mostly concerned with the math behind the forces and angles for set up and ride quality.

Since I've been out of the hot rod arena for a few years, I'm checking to see if my thinking is still the most current "best practice". This isn't going to be max performance or Pro shop built high dollar. I can only hope my skills make it look near that way at the end.

Car goals: 75% street and stop and go (I'm outside of Washington D.C. right now), 25% back roads and some autocross / track days if I can drive the car there. I'm not trailering the car to an event. Most companies don't make sheet metal, never mind parts for a 1949 Cadillac, which necessitates the fabrication approach I'm pursuing. The old C10, mono piston, front disk swap to 1949 Cadillac is not what I want to do here.

What parts should I look at / does my selection make sense?

1. Spindles - I'm looking at using used C5,C6,C7 uprights / spindles for this (I like this because if I decide to do AWD later I have something there to use) Brakes also bolt right on and are decent price.

2. Brakes - C6 or replacement

3. Control Arms - (This is the part I'm trying to math out along with control arm mounting, size, etc). I may be able to use stock C5 / C6 but I'm waiting to get the car to get frame measurements to determine if I need to make customs ones due to overall track width. Ball joints along with car weight / C.G. / ride height become my next thought - it's not a corvette.

4. Rims / Tires - I'd like to run a wider tire and plan on using rims that make the car look like it's still on a 15" rim to make it look period correct and use a hubcap. I'm open to rim and tire sizing opinions but my main concern is tire availability and cost. It the tires are so expensive it's a pain to maintain well that's just not for me. Common wider sizes from a Camaro / challenger /older Corvette is where I've been looking so far.

5. Rear axle / Rear Suspension - I may try to do an independent rear by using something out of a more modern Camaro. It may bolt up, or I may have to build control arms and may as well use Corvette uprights to match at that point unless a better upright is recommend. If independent rear is off the table, it's a 9" floating that I'll weld in a jig. Are we still using 3 links or has someone found something better for this type of application?

6. Engine - I'm going back and forth on this. I'm going to see what shape the 331 Cadillac is in first as 1, it's tied ot the VIN, 2. Its the original engine and kind of cool / different at this point for a build. I know it makes no power, but I'm thinking a mild rebuild (pistons rods, hone, balance) 390 Cadillac Heads and a set of VS mirrored turbos may push that thing to my power goal of ~450 RWHP / TQ. If it's trash, I have a 6.0 that was rebuilt with forged internals, Bullet cam, and texas speed intake with A/W intercooler and twin turbos. I have it kicking around.. but it's way more than I want this car to be... but it's an engine.

7. Transmission - T56 magnum or 8HP90 (or similar) I'd like to do AWD, but I cannot find a way to couple a T56 Magnum or 8HP90 to a transfer case (Maybe SCS gearbox - "Straight Through" and disconnect the front differential electrically, but I'm waiting on the car and for other things to be answered before I pursue that research more).

8. Suspension - Coil-over or if I can get a similar setup to the magnetic adjustable ride that Chevy uses, that would be nice and allow for more general use than all out track slayer and slammed ride.

Is there a program that people use other than building this all piece by piece in fusion 360 and seeing how it all fits and works together prior to raising the cutoff wheel and grinder? It's still cold enough that I wouldn't mind building this plan virtually first to test out a few concepts for the best solution. Please find the holes in my suspension idea. The engine and transmission stuff is mostly there for power, packaging and weight reference info for now.

I need to change this user name.. it's not "Cadillac's and Dinosaurs" enough.

Pics tomorrow / Friday once it's here and I start tearing into this. May start a youtube channel too idk.

- Alex

[dhutton]

Looking forward to this one. Awesome project.

[wfo guy]

I'm a believer in full frames. I would use the aftermarket suspension because I'm not a suspension engineer. I'm not a fan of old engines. Your car, your choice. But if you intend to drive it a lot and don't have modern items, I think you may find a reason to not enjoy the car. In my world, all of my projects have to be as good as modern stuff or I failed. Just my plan, nothing else meant for anybody else. When you spend your money, it should be your plan.

[OLDFLM]

If you haven't seen this thread already it may provide some inspiration:

https://www.pro-touring.com/threads/...ghlight=fiddie

[Joris69velle]

Cool project.

I make and sell adaptors to incorporate the full c5 front subframe and suspension. That might be an idea for you

Joris

[dhutton]

I stuffed a full C5 suspension, steering, brakes and drivetrain including a stretched torque tube under my 56 Chevy Cameo pickup. Send me a message if you would like more info. I don’t want to muddy up your thread.

Don

[Qua-Hoon!]

I'm a believer in full frames. I would use the aftermarket suspension because I'm not a suspension engineer. I'm not a fan of old engines. Your car, your choice. But if you intend to drive it a lot and don't have modern items, I think you may find a reason to not enjoy the car. In my world, all of my projects have to be as good as modern stuff or I failed. Just my plan, nothing else meant for anybody else. When you spend your money, it should be your plan.

Thanks for the reply! I always appreciate the dialog. Totally understand this point of view as I'm usually in this camp as well. 5 of the 6 cars I've built and restored have been LS swap, T56 or 4l80 and I do keep getting better at doing the swap each time. I'm approaching the Cadillac engine idea like a caveman.. "piston go up, piston go down - make powa, head = restriction, boost maybe fix all problem, displacement = displacement, add cooling".

After I pulled this thing down the driveway I also agree with you.. this age of a car needs a full frame. They just are not beefy like cars from even 5 years later.

I built a 1957 Cadillac with a 365 Cad motor and 4l80e it's not a rocket ship but still has fun torque. Currently I daily drive a C7 and know I can't build a car to contend with anything like that with my current budget and car knowledge / fabrication tools and ability. So I'm hoping to make this just something a little different (mostly suspension focused), and challenge myself with making enough power out of the 331 if the engine is still salvageable. Should know more this weekend if it stop raining.

- Alex

[Qua-Hoon!]

Hi Joris! I may go this route so I'll keep you in mind for sure. Current opinion of my frame by me - a non expert - is that it's too weak to do any sort of spirited driving in. But we will see. Stick around and find the holes in my plan though, I always can use a second opinion from others that have done something like this before.

- Alex

- - - Updated - - -

Thanks for this link OLDFLM. I'm checking this out now over coffee. Similar era car = similar problems I'm sure.

- Alex

[Joris69velle]

[QUOTE=Qua-Hoon!;1396620]Hi Joris! I may go this route so I'll keep you in mind for sure. Current opinion of my frame by me - a non expert - is that it's too weak to do any sort of spirited driving in. But we will see. Stick around and find the holes in my plan though, I always can use a second opinion from others that have done something like this

Those would be to use with a new frame of 2x4 tubing. Not to tie into an existing frame.
But either way ill watch the progress

[Qua-Hoon!]

Just a small update. I stripped out the interior and power washed the car. I think 5 lbs of dirt / mud came out of it.. I wish I thought of doing the frame as well because it has a ton of dirt on it .. but oh well.. it'll get dusty. I then pushed this tank into the garage and took the front end off to gain clear access to remove the engine. Hoping to remove the engine and transmission today and do the assessment on the engine. Check out this suspension. The upper control arm is also the shock. One thing that's good that I've noticed so far is that the engine is further back than I thought, and the front suspension is in front of the engine. I can also move it 2 more inches back before the firewall needs modification.

- Alex

[ZZ430]

I am really liking this project!

Alternative body style is an understatement. Going to make a really cool ride.

How about that hood release cable? Talk about ahead of it's time, wow.

I like the idea of using the old motor for a base power plant. Maybe with modern touches such as fuel injection.

Good luck and keep us posted!

[Qua-Hoon!]

Thanks for the post!

I may attempt fuel injection but I know the way the heads sit with intake manifold opening I'll have to lay those injectors nearly horizontal to get them aimed at the valve. I may give this more thought when I build the custom intake manifold if this 331 is good to use.

- Alex

[wfo guy]

Just a thought: any old engine can be improved with a slight raise in compression, a modern ignition system and some kind of efi. Eventually it will come down to whether you intend to drive it everyday or just for special events. because you have exp., you are aware of the parts availability to achieve your goal.

[Qua-Hoon!]

Completely agree. I'd like to actually drive the car as it's fun to see on the road. This is why I'm not shooting for the 1000 hp LS build. I want to say the 331 came from the factory with something like 7.5 to one compression. I figure if I can move that closer to 9 to 1, better breathing 390 Cadillac heads, and maybe quick spooling twin turbos, this car should have tons of pep and be fun and weird. Now if I can figure out this frame stuff and setting ride height so it all makes sense.. then I can look into doing this as AWD as well. Currently figuring out the bends to acheive X ride height and performance is the part I'm researching and making sure I have a solid grasp on before I start cutting anything.

I purchased an engine hoist and it didn't come with any hardware.. I thought I could just bolt my leveler in today and yank the engine.. but the slot on the hoist boom was too small.. so I purchased a hook.. it'll be here Tuesday. Until then.. I get to try an learn more frame design.

- Alex

[dontlifttoshift]

If the track width works, and I think it will. I would use Corvette stuff for sure. Cut the frame off near the firewall and build from there. This was a Heidts clip on a Buick but everything is quite similar to your Caddy.

[Qua-Hoon!]

Hi Donny! Thanks for the reply. I think I'll find some used C5 / C6 uprights and control arms to start planning this thing and see how it lines up. Looking at the pictures you provided, how did you know how much to move the front stub / cross member up / vertically? This is part of the design I'm trying to determine for myself as the frame rails are quite straight on the 49. I know adding that bend would drop the body.. but wouldn't that also mess up the rest of the front panel alignment? (I have about 1 inch of shim on the front core support). . Also what did you set the ride height to and does it scrape? I've been considering 5"

- Alex

[dontlifttoshift]

Pick wheel and tire diameter.

Pick ride height.

Set frame at that height and cut off anything that is in the way of new suspension.

Install new suspension.

Everything in between there is simple math based on spindle centerline. 5" is a good number, the Buick isn't that low because it didn't need to be. We wanted the wheels wells full and for it to look pretty stock.

Before cutting the front of the frame off, I made fixtures to locate the core support and bumper mounts. That is why I included the pic of the whole chassis on the table. After the new clip is on you can either weld those pieces back on or fabricate from scratch like was done here.


Sidebar. This is an enormous amount of planning and work, especially if you have never done it before, and doubly so if you are equipment, space, and ability limited. While I am capable and have everything needed to pull this off at a relatively high level I would absolutely do this first.

https://roadstershop.com/chassis-and...8-53-cadillac/


I also understand that everyone has different priorities for builds. For some the build is the fun, I would rather drive.

[Qua-Hoon!]

Thanks for the walk through. I've looked at RS stuff and previously purchased a front clip for my C-10 when they still made them. I'm just not in a position to buy a 30k frame with brakes and an axle right now. Maybe in a couple years. Also, this is the next step for me in building cars. I'm not incompetent, just trying to learn and plan before I make the first cut because I've never done it before. I still think I can do it myself. I just need to plan it completely to make sure it's right, as it's a big planning event like you said. I'll post some drawings soon for some hopeful feedback from everyone in the coming weeks. Thanks for sharing how you did your build!

[OLDFLM]

Just throwing this out there... you could graft a 2nd Gen Camaro/Firebird front subframe on the car and bolt on some tubular upper/lower control arms and add a sway back and a quick ratio steering box and be light years ahead of what the 49 came with originally. There's probably a bolt on kit somewhere something similar, and not have to graft on a different subframe, idk?

Rear suspension could be redone with RHE truck arms easily or a torque arm or 4-link. Upgrade to C5/C6 brakes all around (KORE3) and add coilovers of choice for ride height adjustments. Then find a 500ci Caddi and put a Terminator TBI EFI and drive the snot out of it! 1000hp LS motors are cool, as is rebuilding the stock 331ci motor but I think there's a better way to get to your desired goal. My dad always said "all it takes is cubic inches or cubic money to go fast!"

The biggest question you have to ask and answer for yourself is "what are you REALLY going to do with the car?" Auto-cross? Cruiser?

Look up Jeff Schwartz 82 Cadillac Fleetwood Brougham that ran the Car Craft Real Street Eliminator back in the day... that 4,000lb car didn't have a C6 suspension nor an RS chassis and embarrassed a lot of expensive sports cars by upgrading the bushings, increasing positive caster, shortening springs for ride height, big sway bar, etc. IIRC he narrowed the rear frame rails to get a wider tire out back, boxed the stock control arms and added a 1" sway bar out back with KYB shocks all around! He used a Trans Am 14:1 steering box and 12-in GM brakes with performance brake pads and stainless steel braided lines. And he did it all with a 500ci Caddi! .

[aaroncorvette]

What a fantastic looking car those old Caddies are.

It'd be nice to keep the Caddy engine, up the compression, 390 heads, cam etc ignition and FI. The old engines look better and perform great with a few updates.
The newer engines are great but there's just something about the old engines.

Looking forward to updates!