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#1
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New Rear & Suspension
Hello all,
I'm in a state of analysis paralysis. I'm putting a new motor and trans into my 68 firebird and the old 10 bolt won't live long with the new combo and the leaf springs are tired and need to go. Motor is putting out 700+ lb/ft torque and 4L80e behind it. Car weighs in right at 3600 lbs with sub-frame connectors. The chassis is otherwise stock and I would like to avoid cutting things up. I've heard the pros for keeping or updating the leaf spring suspension but I'm bent on putting in a modern set up. I'll be putting in a 9" rear but I'm torn between a torque arm setup or a triangulated 4-link. (Ridetech 4-link vs Chassis Works G-Link Torque Arm). The car will be mostly street driven but will go to the dragstip from time to time and I do intend to put slicks on it. Knowing the dual purpose plan, which suspension type would you recommend? I thank you for considering my questions.
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1968 Firebird IAIIa 522 340 E-heads Northwind with XFlow TBI 4L80E 3.50:1 Rear |
#2
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Of those two systems, I choose the G link for two reasons.
1. The motion ratio is much better 2. The ridetech system uses a single shear mount for the coilover. Single shear is fine for shock loads. I don’t trust it to hold the weight of the vehicle. All that said, a quality set of leafs would be my pick for your use case. No need to reengineer the wheel on this one. I would have a custom set of leafs built for your need. They’ll be expensive at around 800-1000 for the set but you’re still ahead on cost for the bolt in coil over systems.
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-Jason 1969 Pontiac Firebird |
#3
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I thank you. I too have been leaning more towards a torque arm.
Since you did mention the leaf springs, which manufacturer would you be inclinde to go with. One of the reason I'm steering away from the leafs is the lack of adjustability and don't want to hassle with the what if the springs are to tall or low, too stiff, too soft. I like the idea of having some adjustability with a coil over solution.
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1968 Firebird IAIIa 522 340 E-heads Northwind with XFlow TBI 4L80E 3.50:1 Rear |
#4
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I would talk to global west about your needs. You may also consider talking to Guldstrand Motorsports. I’m not certain if they do leafs anymore but they used to do race spec custom stuff. You can also lean on the local circle track guys in your area if they are around. The street stocks will be using leafs for the most part and there’s probably a decent place locally to you.
Having adjustability is nice and people market coil overs for that but honestly 99% of people once they get the car set where they want will never touch it again. For a leaf setup you can use a stock or just slightly de-arched spring then tube ride height with blocks. It’s a little bit more work initially, but the likelihood of you changing that at any regular rate is pretty low. I’d you’re doing street and a bit of drag, just having an adjustable shock would get you most of the way there.
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-Jason 1969 Pontiac Firebird |
The Following User Says Thank You to JLMounce For This Useful Post: | ||
#5
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Quote:
GT |
#6
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X2, they work great and don't require any modification or welding.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
#7
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If you are just worried about the rear surviving and launch I would echo what others are saying about sticking with leafs.
If you want a more modern ride however, you are probably on the right track. I have all new components in the back of mine with an 8.5 corporate unit. The rear of the car still rides like a log truck over bumps compared to a new car. The front isnt bad, but the rear sucks over potholes.
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1967 Firebird 462 580hp/590ftlbs 1962 Pontiac Catalina Safari Swapped in Turd of an Olds 455 Owner/Creator Catfish Motorsports https://www.youtube.com/@CatfishMotorsports |
#8
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I have a stout 455 with a 4l80e and I put Global West cat5 leaf springs in it along with their subframe connectors.
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#9
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Speedtech's suspension is really nice that could work in many scenarios.
https://speedtechperformance.com/pro...7-1969-camaro/ |
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