[68 BlueBird]

The front end of my 68 Firebird has dropped ~2" since I installed the IAII 535 and 4L80e. The tires rub the inner fenders during moderate cornering. The front end was at a normal height with the stock 400 and Muncie M21. I need to get new springs, but have no idea where to start. Searching the subject doesn't help much, as most discussion involves lowering the ride height, not picking it back up. I guess that having data on the original 400 front springs would be a start, but I can't find that info either. I really don't have time (or money) to be swapping out springs until I find a pair that does the job. I'd like to get it right the first time, if possible. I'd appreciate any advice on how to select the right springs. Thanks.

[JLBIII]

I went with Eaton springs. Their tech was most helpful on what springs I should run. Installed their rear leaf springs last summer on my FB. Front end is apart right now and have a matching set of Eaton coil springs ready to go in.

https://www.eatondetroitspring.com/

[68 BlueBird]

Thanks. That's a start. I'll give them a call today.

[punkin]

Originally Posted by 68 BlueBird

The front end of my 68 Firebird has dropped ~2" since I installed the IAII 535 and 4L80e. The tires rub the inner fenders during moderate cornering. The front end was at a normal height with the stock 400 and Muncie M21. I need to get new springs, but have no idea where to start. Searching the subject doesn't help much, as most discussion involves lowering the ride height, not picking it back up. I guess that having data on the original 400 front springs would be a start, but I can't find that info either. I really don't have time (or money) to be swapping out springs until I find a pair that does the job. I'd like to get it right the first time, if possible. I'd appreciate any advice on how to select the right springs. Thanks.

I'm in a similar situation where I'm putting in an IAII and 4l80e. My motor is aluminum so I'm expecting the front to come up a little.

My 68 originally had a 350 motor and a ST300 trans stock. I've never replaced the front springs and and it sits very nicely with a 455 and TH350 in it. The stock springs look very good to me with this combo. I did put a heavier front sway bar and shocks to help with the pitch and roll but none of that was done for ride height considerations. Hope that helps a little. I'm a bit ahead of myself here but if/when I get the motor in and if I need to replace my springs, you're welcome have my factory 350 springs.

[68 BlueBird]

Originally Posted by punkin

I'm in a similar situation where I'm putting in an IAII and 4l80e. My motor is aluminum so I'm expecting the front to come up a little.

My 68 originally had a 350 motor and a ST300 trans stock. I've never replaced the front springs and and it sits very nicely with a 455 and TH350 in it. The stock springs look very good to me with this combo. I did put a heavier front sway bar and shocks to help with the pitch and roll but none of that was done for ride height considerations. Hope that helps a little. I'm a bit ahead of myself here but if/when I get the motor in and if I need to replace my springs, you're welcome have my factory 350 springs.

I seriously doubt the front end will come up, even with the AL block. The 4L80e with converter and fluid is well over 200 lbs. The G-Force crossmember (which is the one most people use) is also much heavier than stock. The rotating assembly will also be heavier than a stock 400/455, unless you're running an exotic crank/pistons and AL rods. The AL block will definitely help (I regret not spending the extra $1K for it), but I think you'll still be heavier then when you started.

[punkin]

I once thought I could see the bottom of the money pit. This could be the excuse I needed to go coil overs.