preparing things for a later pro-touring build

[dingo84]

Hello everybody! I'm currently overhauling my 81' Supreme. Its only going to be a cruiser this time. I've taken care of the frame and chassis right now and preparing for re-assembling with all new polyurethane bushings for the body mounts.
For now, this build is going to be almost stock in the under carriage. I can't afford to buy all the performance trailing arms and coilovers etc now..
The engine is a 76' L48 350 with some performance parts, not much. And I'm still going to use coloumn shifter with my TH350. When it's time to upgrade this ride to pro-touring, I'm going to build a LS1 with T56, rear discbrake conversion, wilwood front brakes, swap out the bench with recaro pacecar seats and so on.. The shocks and springs are stock now.
I were just thinking about what I could do while the body is off-frame.
One thing I will do is lay new fuel lines, including a return so its ready for hooking up with the injection on the later build.
I've seen people doing different things with their frame when they go pro-touring. I'm not going to compete on track professional, but I wan't the car to handle like a sports car and maintain some daily driving comfort. I know the poly body bushings helps for all-round stiffness. I were thinking about if its necessary to notch the rear frame to fit wider wheels/tires. I'm not going to slap on wider than 275.
I need to change the rear lower trailing arms, since the stock thats on now has severe rust. I'm going to buy the "PUREMUSCLE" boxed arms.
Later when I'm going to upgrade more, I will buy the upper boxed adjustable trailings arms, UMI performance front lower and upper trailings arms, swaybars front and back, some coilovers front and back.. But I''ve noticed I will need to weld in some new brackets to fit rear aftermarked coilovers.
Is there anything else you guys recommend me to do before I mount the body back on frame? I don't want to lift the body AGAIN if you know what I mean THe frame has been sandblasted at least.

 

[tetomas]

Box in the open sections of the frame, and add the G-Force extension on the drivers side, so it will be easier to put in the correct crossmember later. Also if you wanted to you could cut and weld the front crossmember to fit the LS oil pan. You can cut and weld the crossmember with the body on, or use an oil pan that fits without cutting(CTS-V?).

 

[307 Regal]

From what I've read, you'll wanna have some flex somewhere in your rear suspension if you're going for a pro-touring build. For instance, you could have rubber bushings in your boxed CAs or you could have one of those "roto-joints" on at least one end. I have UMI uppers and lowers. Both pairs are a polyurethane/roto-joint combo. Roto-joints allow your 4-link to articulate and prevent binding. Rubber can do the same to a degree. Poly, though, only flexes slightly. It's alright for drags, but during corners it may put stress on your CA mounts. Also, I've read that once poly has compressed to its limit, it can unexpectedly decompress causing snap oversteer.

 

[SickSpeedMonte]

If you want the car to handle, stay away from boxed trailing arms. You want that torsoinal flex that the stock arms give. Stiffening them torsionally causes the suspension to bind, which gives the snap oversteer that 307 Regal mentioned. The johnny joints or roto joints available in many aftermarket arms try to eliminate torsional stiffness as much as possible so that you don't bind the rear suspension in roll.

Plating/boxing the open channel sections of the frame is a good idea. Running new fuel/brake lines is good too. On a Monte, a 275/40R17 fits fine without frame modifications. Use 5" backspacing on a 17X9.5" rim. 4.75" BS on a 17X9" rim. A 10" wide rim won't fit without rubbing. (Not sure if the Cutlass wheel arch is different enough to change this.)

Are you doing anything to protect the floor pans? I POR-15'd the floors and up in the channel of the body where the frame goes while my body was off. It was a long tedious process though, I wire-wheeled as much of the old undercoating off as I could and then sandbalsted it in my garage with nothing more than a $20 hand-held sand blaster and some plastic sheet from Home Depot. It took quite a few refills, but I got it done in a solid day and I didn't pay someone hundreds to do it for me. Then I had to use the Marine Clean, Prep & Ready, and finally painted with POR15. The whole underside, up the firewall, and inside the cabin and trunk as well. One day I will probably spray bedliner on it too. My body is coming back off of the frame when I build a new chassis for the car, so probably then.

 

[dingo84]

This sounds good. But I actually want to fit some 20" wheels , I've seen them on a G without looking too big. 20x9" and 20x9,5 maybe?
Yes the car god sandblasted and coated underneath while the body was still on the frame, since I had to take the oportunity to get the crew's help since they did a blasting job on a ship that day.
Well now the snug spaces that he did'nt get to, need to be wirebrushed and coated after I'm done welding. I'm using firstly owatrol (a oilbased penetrating paint that keeps all rust out), then arcanol (a tough primer paint like benga, just better). After everything is painted and mounted with polybodybushings, I'm gonna coat some tectyle as well for additional protection.
I think I'm gonna order the round rear trailings arms instead after what I've read.

 

[85Gold-Heart]

I want to run 20x8.5 fronts with 20x9.5 rears. Similar but a little different so when it comes time for the wheel swap please share the info