One of my favorite things to go after when writing an article is fixing incorrect "tribal knowledge" when it comes to the C5 Corvette. Brembo brakes with much larger rotors will somehow stop worse than stock? NOPE and here's the data. Various parts don't weight all that much and are insignificant? Here's the actual parts weighed and total weight journey of my C5 Corvette track car. These articles are fun to write, have a long shelf life as they disprove very misguided folks, and in general put a smile on my face.
So imagine my excitement when a person recently posted in a group I'm in asking if they would need to get an alignment after dropping their subframe only to receive two polarizing sets of answers. Many folks said no it can only move a small fraction, while a bunch of us who've seen how much slop there is when installing the subframe said yes... but there was no data!
As "luck" (or misfortune in my case) would have it, I'd dropped my subframes a bunch since my last alignment. I first dropped it to make room for installing older Kooks Headers, then I had to drop it again to remove the steering rack as part of a heads/cam/intake job. That means the front of the car has now been loosened and potentialy shifted twice! The "fun" didn't end there though, as my transmission lost 4th gear synchros at my 34th event necessitating replacement, and then my torque tube sheered the bolts off the input shaft at my 43rd track event. That's two potential shifts per end of the car. An alignment was quite over due at this point.
In the Portland Metro area, and more specifically Vancouver WA, I highly recommend you work with Carl's Alignment and Brake. They specialize in classic cars, and while the C5 Corvette isn't quite that old yet, their in depth knowledge of so many different cars with so many options for customization and modernization means there isn't a car they can't dial in.
I took my Corvette to them and dropped it off. Alignment had been previously performed and done by Camarillo Alignment down in Southern California. They are the only shop willing to do custom alignments in that particular area of SoCal, so if you happen to be there and need work, I can endorse them. We set my car up with 0 toe front, -2.6 degrees front camber, and -1.35 degrees rear camber. Caster was set to "max" which should have been about 7 degrees or so.
So how did this numbers hold up after all of my sub-frame shenanigans?
The sheet above captures the state of my car before and after alignment. You may not be entirely familiar with these sorts of sheets or what this all means, so I'll break it down based on my understanding of the numbers.
Up front, the front subframe had clearly shifted, resulting in a half degree of camber shift towards the passenger side. Half a degree may not seem like much, but when it gives you -3 degrees on one side and -2.5 on the other... that's a big shift! A perhaps more important number to observe though is that the toe went from being 0 to being TOED OUT! That will definitely impact the car's handling along with it's tire wire. Beyond that, a notable amount of caster was lost. The front was definitely quite out of wack!
As far as the rear is concerned, The camber hadn't actually shifted that much, and due to some limitations of Delrin bushings in the rear lower control arms I couldn't gain any further camber there on one side at all. What did shift though is that the car had gone from having a slight bit of toe in to actually being ever so slightly passed even into barely toed out territory. So not a huge shift in the rear, but still if you were relying on the toe-in to help stabilize the car at speed... it can go away!
So what's the takeaway here?
This is all just an "N of 1" aka just one dude showing you what they experienced. This also could have just as easily been me saying nothing shifted it's no big deal. The takeaway is, there's definitely some slop in the subframes that can potentially on reinstall lead to your car having alignment shifts., Reinstallation can result in shifting the car around, but you could also get lucky.
Is it enough to matter on the street? I'd say so, especially if your camber numbers are closer to factory settings. If you're only at 1 degree of camber and the car can shift as much as a degree side to side... you could wind up at zero camber! That said, the intensity with which any person who values their life drives a car on the street is much lower than the track, so it may not ultimatley matter...
Is it enough to matter on the track? Depends on your goals and just how performant your driving is looking to be. If you're just out having fun not chasing lap times and just chasing those endorphins, well then I can confirm after having driven 10 events or so on a obviously shifted setup that you can not just have fun, but even set some new PBs. If you are after outright best performance and trying to chase a podium in time attack or some other event though... seems to me there's clear data demonstrating you need to check your car! Plus there's tire wire considerations, and just in general if you're trying to validate "Did this improve my car?" it'll be a lot harder if your alignment is now all out of wack!