Suspension/Chassis Suggestions - 70 Dart Swinger

I generally look at late model Mustangs for take-off's. The Challenger/Charger wheels are a bit of an unknown since the published bolt pattern is 5x115mm. I have measured wheels that show as 5x114.3mm(5x4.5) but I have also measured new hubs that had the 115mm pattern. I wouldn't run a wheel with the wrong pattern and I can't nail down which it is supposed to be.

I have found '09 GT500's to be a reasonable target for wheels. But I plan to run Scat Pack Brembo's at some point so I have been a little on the careful side.

This is the wheel I bought for the front, haven't decided on the rear wheels yet. Forgestar Mustang F14 Monoblock Piano Black Wheel; 18x9 F15189066P35 (15-23 Mustang EcoBoost w/o Performance Pack, V6) - Free Shipping

When I bought them, they said they worked with an '09 GT500, but now they don't. Not sure what changed.

On a side note, I am of the opinion that Mopar published a rounded value for the bolt circle (rounded up) and that the original parts were 4.5" bolt pattern. I have several data points that lead me to believe this, but they are kind of pointless since the aftermarket parts suppliers appear to be building to the true 115mm bolt circle so I don't trust any of it anymore.