1972 Monte Carlo - Resto Mod

[Alwhite00]

Looking good. Make sure to fit your chrome trim before paint.

[dr.bombay]

Nice to see another Monte Carlo build. I've been working away at mine little by little for about 7 years now.
https://www.pro-touring.com/threads/...71-Monte-Carlo

Love it!

[dr.bombay]

Some more surgery around the back window. Picked up a replacement trunk fill panel. It fit pretty well except one of the sides seemed to have a slightly different angle on the drop down tabs than the existing quarter panel. The location of the channel and the overall shape was dead on though

[andrewb70]

Looking good. Make sure to fit your chrome trim before paint.

This is excellent advice. When this area was repaired on my GTO the shop actually used the OEM as a guide to build the area around the window.

Andrew

[TonyHuntimer]

Cool! It's good to see people building more than Camaros.

[dr.bombay]

3d Tetris coming together. This was one of the major rust areas of the car. Once this is done, the decision will be to move onto mechanical or patch up the roof. I started using 0.023” wire but that was not conveying enough heat to get good penetration for plug welds so I switched to 0.030” wire which is working much better after I spent a little time on the welding table getting my amateur technique dialed in. I am using MIG process with C25/Ar75 shielding gas.

[dr.bombay]

Done! Now time to move on to the front suspension

[TanMan]

Great! Since you wrapped up that metal replacement around the back window I can go ahead and bring over my ‘70 Grand Prix so you can do the same thing;)

Seriously though, loving this thread. Great work so far. Montes and GPs have so much in common so I enjoy these builds a little extra.

[dr.bombay]

I am a fan of the early GPs and also the colonnade era GA’s if only I could find one. The bird beak and catwalk grille in a world of bland camrys and accords is just too cool


Up next is the front suspension. After much research and considering my budget and use case, I decided to go with UMI Stage 4. I like the Viking front shocks and the swivel (roto) rear control arms. I am also replacing all the steering linkages and the steering box. This car is a survivor meaning that there are dust boots and bushings on here that were manufactured when Orange County’s very own Richard M Nixon was in the White House. And like tricky dick, I am also “not a quitter” when it comes to wrenching into parts unknown. Approaching this with a 1/2” ingersoll-rand impact and can of Kroil penetrating lube.

The suspension came apart fairly easily. The front spring are OEM and were fatigued enough that after splitting the ball joints and swinging down the lower control arm, the springs just fell out. Almost didn’t need the floor jack to contain the potential energy in the spring after all

[dr.bombay]

Cleaning up the factory welds. There are areas of the frame where the old stick weld bead is not even on the seam and other areas where the pieces seem to be held together by weld spatter. It is truly shocking that these cars have survived 45+ years




Plan here is is to reweld the key load transfer/stress points like the cross member-to-frame joint and the abutting channels near the control arm pickups

[dr.bombay]

Viking Double adjustables and UMI tubular arms mocked up

Then came a ton of additional grinding and re-welding of the frame: 1) seams on the front frame horns (the OEM weld beads weren't even on the seam in places), 2) the engine crossmember connection to the longitudinal frame rails 3) seam around the rear lower control arm ears and the frame

Then front suspension mocked up


And here is the top view with fender liners out. 12.7:1 boregeson steering box and UMI bump steer tie rods. Next will come a new center steering link and idler arm drag link. The gear looked original and there was a decent amount of play in the idler arm joint and the inner air rod links. I will reuse the original Pittman arm as I can't really see how that thing would even need to be replaced based on its design.



I can thank all this quarantining for the push of activity on the car!

Some bugger-ey welds on the frame below. looks like I need a little less wire speed and maybe a but slower travel speed. I am certainly no pro but I am having fun!

[dr.bombay]

Now time for brakes. I decided to go with a C6 Z51 setup to keep as many OEM parts as possible (pads, rotors etc). I had a bunch of c6 parts lying around from the corvette I used to own so why not recycle? I used KORE 3 for the brackets and other components (Tobin is awesome). I used a 72 A-body from DRUM hub and had a local machine shop turn them down and chamfer the outboard face to fit inside the corvette rotors. I also replaced the studs with 7/16x20 ARP extended studs. upon pulling everything together, I realized how much of a pain the long lug studs are - you can't get the rotors on/off without unbolting the caliper housing from the spindle bracket. ugh. Live and learn.

The tolerances on my drum hub and spindle were such that I had to slightly shim the caliper brackets to center the caliper over the disc. Kore 3 was super helpful in answering my 1000s of questions and getting this sorted out.

Note to self/others - never use a crescent wrench to disassemble brake lines - trust me and use line wrenches instead!

So damn sexy!!

[dr.bombay]

Since stock wheels or even 17" stock "reimagined" wheels are not going to work with the caliper diameter of the C6 z51 brakes, i needed to go to 18" for wheels. rather than getting out the micrometer and trying to nail stance and fitment with all the new parts coming together (aftermarket suspension, brake hubs, calipers), i decided to keep it simple for now with the expectation that once i get alignment, ride height, and some real-life miles, I can think about custom offsets etc.

ended up going with TT2s in 18x9 up front with 265/40/18s. I will go with 18x10 with 295/40s in the rear. to lear the depth of the c6 calipers, i had to run 3/8" spacers upfront (not ideal but will work for now). I havent dialed in the camber but it looks like it will be pretty tight against the outer lip with upon compression to the bump stops.

[andrewb70]

Nice progress!

Andrew

[dr.bombay]

Next step is the rear end and rear suspension. I know the cardinal rule of car restoration is to tackle things system-by-system to not end up in a demoralizing morass of loose parts. However, i will bend this rule a bit to pull the fuel tank and fuel lines to get access, inspect the trunk floor/drop panels for rust.

Pulled the stock fuel tank which was actually in good shape. Since the car had been regularly driven, the innards were clean and there were no leaks or rust. there was a small dent on the bottom which my son wondered if it might have been the result of 1970s style / Fast and Furious Tokyo Drift (yes a Monte was character in that film) car chase jump... i think (hope?) not... Which gets me wondering - how did that golden era of car chases coincide with the rolling sofa cars of that time? It didnt cross my mind as much as a kid watching Steve McGarrett chasing bank robbers on twisty highways in Hawaii in a 5000 pound Mercury Marquis with 7" tires

But I digress. The tank and sender went up for sale and went to a new home in a local kid's chevelle build. My plan is to get a dedcated EFI tank rather than messing around adding an internal sump box. With the tank out, i could get a good look at the floor which looked great and free of rust. the whole area was washed down, scotch-brited, and primered with factory-esque Zinc Phosphate. I think it was Zinc Chromate from the factory but i understand that stuff is mega toxic.



Oh and the drab green primer color was chosen to match the remaining primer i see under the floorpan and inside the inner structure. Some archeology tells me that this was consistent with GM assembly practice in the Van Nuys plant where the Monte was built in '72. Again - not going for a purist restoration but want to keep the history where possible and where it doesn't conflict with my modernization goal.

[dr.bombay]

One big chunk of the decision-making for the driveline (and the budget) was the rear end. the car was originally a 350 2bbl with a TH350 so maaaybe it was making 200hp from the factory which justified the 8.2" open carrier 10 bolt. I heard from builders that the best case scenario for this with upgraded guts was about 400hp. That was not going to work for what i had in mind for the car (manual trans + 475-500 whp end of day). Although it is probably overkill, i decided to go with a 9" assembled by a local builder with whom i have worked with before. Used a Currie housing with 1967 width (slightly narrower than 68-72 but with the same mounting points/spring perch location) True-trac diff and 3.50:1 gears. Corvette c6 z51 rear brakes went on (again - hardware from Kore 3 less c6 rotors and calipers I had laying around) with fitting for parking brakes which i will have to figure out later. the UMI bushings didnt quite fit in the currie housing so i went with the currie articulating joints on the housing end (the UMI joints are on the frame-tab end) so the upper trailing arms will be double-jointed. UMI verified that this there are no issues with doing this. the only thing i am a bit worried about it NVH but i wont be able to judge that until the car is on the road.

[dr.bombay]

Hey All,

Between work and general life responsibilities, the Monte has been catching some zzz's. To add to that, my son convinced us to let him launch another car project (yes - two concurrent car projects is a recipe for getting 0 car projects done...). I will say wrenching on car is a bit therapeutic with all the goings on in the world. Here is the rear end in the car with the UMI UCAs and LCAs. I'm using some heater hose on the two spring ends as isolators. With the fuel tank out, and shocks out and rear end at droop, i can start routing brake and fuel lines. I am a little worried about doing those with the body still on the frame but i am also not thrilled about doing all this on the car and cruising around with 49yr old critical hardware. Its a little hard to see in the pics but i did some gusseting of the rear frame "bridge" to the longitudinal rails and some reinforcement of the UCA frame ears. both ears showed some small cracks near the frame end which I had diagnosed as likely-impact related rater than fatigue-related by a retired metallurgist i know. crack or no crack, those tabs seem really flimsy to me - especially with the limited frame-to-tire clearance that I will have to maintain here (about 3/4" at the sidewall bulge).

[72'Monte]

How's the monte coming along. Hopefully soon I can start my monte build.