Go Back  ClassicOldsmobile.com > Repair & Restoration > Technical & Reference > General Questions
1968 Oldsmobile Cutlass Supreme - Frame off Restoration - Disc Brake/Suspension >

1968 Oldsmobile Cutlass Supreme - Frame off Restoration - Disc Brake/Suspension

General Questions Place to post your questions that don't fit into one of the specific forums below.

1968 Oldsmobile Cutlass Supreme - Frame off Restoration - Disc Brake/Suspension

Old February 10th, 2019, 02:54 PM
  #1  
Registered User
Thread Starter
 
Join Date: Nov 2017
Location: California
Posts: 2
1968 Oldsmobile Cutlass Supreme - Frame off Restoration - Disc Brake/Suspension

I need some help with choosing what parts to get to upgrade my 1968 Cutlass Supreme's brakes and steering/suspension.

This is not a numbers matching restoration, im looking for upgrade that will get the most performance bang for the buck.

I have the frame off and body on a rotisserie. I took the frame to get blasted and painted. I told him that I planned to upgrade the brakes, and steering, suspension.

He suggested that I remove the old parts so that it could be done properly.

Now i need to choose what parts to get so that I can get the frame rolling again and continue to the body.

Looking at the kits at OPGI, there are so many options that I just dont know what would be the best. I have seen some mention that buying parts separately would minimize the cheap parts that are sometimes included in the kits.

Also I noticed the Flaming River rack and pinion setup. Anyone have thoughts on this? I really like the look of their polished steering column's with the tilt, just dont know if rack and pinion is worth the money spent on it?

About body mount kits and the prothane line of mounts and bushings.. Im not sure why im attracted to the "red" bushings and mounts, they wont hardly be seen. Ive also read that they make for a rougher ride. Any thoughts on this?

I will be purchasing door panels and seat restoration kits, as well as headliner and carpeting. I got a pair of bucket seats, and a center console already from a local who was parting out his wrecked Cutlass.

This car is a California car with minimal rust. I have some panels that need to be patched in the trunk, and the front cowl area as well. I may have a line on a 442 louvered hood as and some doors with power windows. Would I need to get power window regulators for the rear windows?

I really wish I had a list of hardware that I could use to get all the correct sized nuts and bolts. I know there is a list in the assembly manual just havent taken the time to add them all up. Also it doesnt list the exact quantity of each bolt required.

Any help you can give, tips or advice would be much appreciated. Thank you in advance.

Robert
68oldscutdog is offline  
Old February 10th, 2019, 03:30 PM
  #2  
Old(s) Fart
 
joe_padavano's Avatar
 
Join Date: Mar 2007
Location: Northern VA
Posts: 31,620
Welcome.

Personally, I don't think the R&P conversion is worth the money. The biggest single difference in road feel between these cars and newer ones is the caster setting of the front end alignment. Since power steering was only an option when these cars were new, the steering alignment used caster near zero to minimize the force required with manual steering. Crank in as much caster as the car will let you - typically 3-4 degrees will make a phenomenal difference in feel, with no cost other than the alignment. If you are rebuilding the front end, I'd consider either aftermarket tall spindles or tall ball joints with stock spindles. This improves the camber change curve while cornering, which greatly improves handling. I'd get a quick ratio (12.7:1) steering box, but be sure that the control valve torsion bar you want. Contrary to what you may read, steering feel isn't only governed by ratio of the box. The Saginaw power boxes use a torsion bar in the control valve that governs how much power assist you get for a given steering angle. The stiffer the bar, the less assist and thus more road feel. Most aftermarket steering box rebuilders only talk about ratio, not the torsion bar selection Finally, get the biggest rear bar you can find. Stock bars on the 442 were 31/32" at the front and 7/8" at the rear. Even with this, the car still understeered. Most people increase the front bar because that's easy (the 1.25" Trans Am WS6 bar bolts in) but that simply makes the car even more of an understeering pig. Herb Adams used to sell a 1.5" REAR bar for the A-body cars to go along with his 1.375" front bar. This really made the car a much more neutral handler. Unfortunately, you'll be hard pressed to find these today. I've managed to score a couple of those 1.5" bars used, and no, they are not for sale. Poly bushings are your call. Anything that prevents unwanted suspension motion will help handling, but at the expense of ride comfort. Only you can decide how to prioritize that trade. If you plan to use poly in the rear, be advised that the A-body rear suspension requires some twist in the upper arms as the suspension travels. The stock rubber has enough compliance to allow this. Poly does not. You can either use stock rubber in the front upper bushings or else get the aftermarket metal ball joint bushings for those two locations.
joe_padavano is offline  
Old February 10th, 2019, 10:04 PM
  #3  
Registered User
Thread Starter
 
Join Date: Nov 2017
Location: California
Posts: 2
Originally Posted by joe_padavano View Post
Welcome.

Personally, I don't think the R&P conversion is worth the money. The biggest single difference in road feel between these cars and newer ones is the caster setting of the front end alignment. Since power steering was only an option when these cars were new, the steering alignment used caster near zero to minimize the force required with manual steering. Crank in as much caster as the car will let you - typically 3-4 degrees will make a phenomenal difference in feel, with no cost other than the alignment. If you are rebuilding the front end, I'd consider either aftermarket tall spindles or tall ball joints with stock spindles. This improves the camber change curve while cornering, which greatly improves handling. I'd get a quick ratio (12.7:1) steering box, but be sure that the control valve torsion bar you want. Contrary to what you may read, steering feel isn't only governed by ratio of the box. The Saginaw power boxes use a torsion bar in the control valve that governs how much power assist you get for a given steering angle. The stiffer the bar, the less assist and thus more road feel. Most aftermarket steering box rebuilders only talk about ratio, not the torsion bar selection Finally, get the biggest rear bar you can find. Stock bars on the 442 were 31/32" at the front and 7/8" at the rear. Even with this, the car still understeered. Most people increase the front bar because that's easy (the 1.25" Trans Am WS6 bar bolts in) but that simply makes the car even more of an understeering pig. Herb Adams used to sell a 1.5" REAR bar for the A-body cars to go along with his 1.375" front bar. This really made the car a much more neutral handler. Unfortunately, you'll be hard pressed to find these today. I've managed to score a couple of those 1.5" bars used, and no, they are not for sale. Poly bushings are your call. Anything that prevents unwanted suspension motion will help handling, but at the expense of ride comfort. Only you can decide how to prioritize that trade. If you plan to use poly in the rear, be advised that the A-body rear suspension requires some twist in the upper arms as the suspension travels. The stock rubber has enough compliance to allow this. Poly does not. You can either use stock rubber in the front upper bushings or else get the aftermarket metal ball joint bushings for those two locations.
Thanks Joe,

I really appreciate your wisdom and advice. Truly worth its weight in gold.

I will research what I can find and post it here before I pull the trigger.

If anyone has any advice on disc brake conversion kits that they liked Im all ears.

Thanks again Joe. You really are the new Dr Oldsmobile!!

Robert
68oldscutdog is offline  
Old February 11th, 2019, 05:40 AM
  #4  
Registered User
 
allyolds68's Avatar
 
Join Date: Jul 2008
Location: Seneca Falls, NY
Posts: 4,246
I have a fairly stock front disc set up and they work great. I don't really don't get why people spend stupid money to add rear discs and oversize front discs. For a "driver" it just doesn't make sense

I just went to a local yard yesterday and there's a 72 Supreme there that has front disc spindles still on it. I can probably get them for $25. Pretty much everything else except the proportioning valve is available from Rock Auto and you're going to buy all that stuff new anyway.
allyolds68 is offline  
Old February 11th, 2019, 05:47 AM
  #5  
Old(s) Fart
 
joe_padavano's Avatar
 
Join Date: Mar 2007
Location: Northern VA
Posts: 31,620
Originally Posted by allyolds68 View Post
I have a fairly stock front disc set up and they work great. I don't really don't get why people spend stupid money to add rear discs and oversize front discs. For a "driver" it just doesn't make sense
But then we wouldn't have all these threads about how these mis-matched aftermarket systems don't clear wheels, or how they can't bleed the system, or how they don't get the stopping power they expected...

Mike's spot on. If you really feel the need to upgrade over the stock front disc brakes, there are two easy things to do. Use the Wilwood D52 calipers in place of the stock single piston calipers. These bolt to the stock brackets and provide about 12% more piston area. Change the 9.5" rears to 11" drums from a 73-77 car. This is an easy swap and clears all stock wheels.
joe_padavano is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
WTHIRTY1
Major Builds & Projects
212
April 14th, 2019 05:31 PM
69442
Cars For Sale
25
October 13th, 2018 03:03 AM
Mocephus
Eighty-Eight
11
November 28th, 2016 08:30 AM
frasco
Major Builds & Projects
4
September 15th, 2011 07:45 PM
DJMatthews
Chassis/Body/Frame
3
December 5th, 2006 01:28 PM


Thread Tools
Search this Thread
Quick Reply: 1968 Oldsmobile Cutlass Supreme - Frame off Restoration - Disc Brake/Suspension


Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.