The Chassis and Engine
Time for something amazing
I went through a a lot of chassis modifications with Doris and after driving her for several years I knew I could do better.
One of the thing we have to deal with in Australia are the compliance rules for light vehicle modifications, they are very restrictive, unlike the USA where you can just purchase an aftermarket chassis with modern suspension components, job done! Here, we need to work with what GM gave us in the 50’s, but that’s OK, with some clever fabrication and newer Corvette components from the 88-94 C4, a fully independent suspension chassis is possible.
Fresh look at an old chassis
There are a number of aftermarket chassis builders in the USA that have made a name building great handling C1 chassis, I love the Art Morrison and Streetshop chassis, but unfortunately no engineer in NSW I have spoken to will approve one. Ho hum, so it’s back to the original chassis, which structurally is pretty strong with that x frame design. All it really needs is some decent suspension with the correct geometry for the wheelbase and that is exactly what the C4 Corvette had! It’s fully independent, lightweight aluminium and readily available as are all the bearings, bushes and brake components. So I went about modifying the original chassis which requires considerable work. Working within the rules of VSB 14 (which is the national code of practice for vehicle modifications), the front chassis rails were removed and new frames fabricated to accept the C4 K frame, the subframe that all the front suspension and steering is mounted on.
The rear was modified to accept the IRS, I used the beefier Dana 44, I had all the mounting bracket supplied ready made from a contact in the USA who also makes modified C1 chassis, which made the job significantly easier.
The C4 has front and rear transverse composite spring and shocks, I’m not a fan and wanted fully adjustable coilovers, so I incorporated those into the modifications. Then finally, due to the size of the transmission, the original X frame design would mean it would be impossible to drop the transmission without removing the engine, so for practicality, I modified and strengthened the cross member so the transmission can now be dropped with the engine in place.
Power train
The easy choice is to go with something LS, there are plenty of options available in Australia and endless aftermarket parts like front end accessories. But then what’s the challenge, wasn’t the idea to use the latest and greatest and surely the LT is the next generation, right? So I picked up a Gen V LT1 from the USA with 2,600 miles on the engine! The car was written off but the front end was untouched, perfect!
Originally, I was going with the 4L70E. It’s a solid work horse, tried and tested (I used the 4L60E in Doris). This more rugged version would handle the 460HP from the LT1 with ease. But then why not push the boat out: 4 gears is good, but 6 is better! The Camaro that used that engine has an 8 or 10 speed auto.
I decided that a 6 speed would be the go. I was concerned that with too many gears the poor car would be hunting between gears constantly, it’s a fairly light car.
First observation: the 6-speed is huge! Like, “that’s not going in the tunnel” huge! Then there’s the shifter especially if you use the TUTD function!
John Ward
> Go back to the 1958 Corvette Jolene page <