Slow 68 mustang - Big Girl Pearl or "Yellow Fury"

[arcane73]

Great project, I love your approach. I don't see much talk so far about chassis stiffening beyond subframe connectors. Any of these Falcon-chassis cars get pretty flexi when you start throwing a lot of power and G forces at them. I'm going to say up front I haven't built this car but I'm putting together a plan for a Maverick so I've put a lot of thought into it...so I could be wrong but use what you want and throw the rest away.

IMO the Maier Racing Shock Tower Brace is exactly the right approach. Combining the Monte Carlo Bar and Export Brace into one piece has to make the whole assembly stronger. There are some really trick-looking, heim jointed shock tower braces out there. To me they look like trying to stiffen something by stringing a chain across it. I'm sure they help but not like a solid structure that ties multiple points together.

Mustang engineers put a lot of effort into stiffening the convertibles. Use their work. The seat reinforcement pan and floor reinforcement plate do a lot to stiffen up the car. You can use them with very little modification. Convertible inner rockers help a whole bunch too. They're a lot more work to put into a coupe, but you could probably modify them to put into the car without having to cut up the floor...or have something made with similar dimensions but built to fit a coupe floor pan. Doing it this way you can use convertible carpet, and until someone tells me I'm dead wrong I'm inclined to think you could install this stuff with structural panel adhesive to keep from having to strip out the whole interior for welding.

Put a solid sheet metal firewall between the rear seat and trunk. A Google search shows people who have done load testing on these cars found that stiffens up the back end a lot.

Trans Am Brace...a small plate that braces the OUTSIDE of each frame rail to the shock tower on the Boss 302 cars.

Boss 302-style engine crossmember. It gussets that curvy crossmember and ties it to the LCA pivot, preventing the bottom of the engine compartment and LCA mount from flexing. Here's an example: http://opentrackerracing.com/product...lby-1965-1966/

Maybe this isn't what you're looking for but it's a whole bunch of ways to stiffen the chassis without taking your car off the road for long, cutting out your shock towers, or going to some high dollar add on chassis. Nothing wrong with that, but you said you didn't want to do those things.

Thanks for the input, John. I appreciate it.
As far as Maier's tower brace goes, I have it sitting in the garage and ready to go on when the engine swap happens. I just managed to forget to add a pic.
I do plan on the solid sheet firewall between the trunk and passenger compartment. That's on my list of things to do when I get it on the road after the engine/trans swap.
I also have the trans am braces as well as some other shock tower bracing on my list. Opentracker has a nice kit already put together. http://opentrackerracing.com/product...kit-1967-1970/
The engine crossmember has been on my list for a while. The one you linked is actually built by a vintage-mustangs forum member (zray) and he sells them through opentracker as well as directly.
https://forums.vintage-mustang.com/1...ml#post8733241



The honest truth about why I'm waiting to do a lot of strengthening is that I'm almost positive the car is bent. It has been kissed in the rear at some point and I'm pretty sure that it's off-kilter. I plan to get the swap done and drop it off at a local place to have it put on their table and see how bad it really is.
That will determine what's getting removed/replaced and what will be salvaged. Once I know what needs to happen with it, MikeH and I can start planning on cutting/replacing the bad parts and trying to get it ready to be straight again.

Of course, all of that progress will go up here as it happens......sometime next year ;)