GT40 Build - GT Forte' space frame - Question about front suspension

Hello. I've just started poking around this forum and, I'm a noob when it comes to building kit cars (please be gentle). I've purchased and took delivery of a GT40 chassis flat pack from GT Forte'. Minus the roll hoop and missing horse shoe assembly, the frame is nice and tacked up (I can fabricate whatever is missing). I would like to focus on getting the frame to roll right now.

I've never worked on anything other than stock suspension componentry. Building out suspension from scratch will be completely new and I hope I'm headed in the right direction.

GT Forte' assembly instructions does not discuss the front suspension geometry. So, I've decided to purchase a cheap set of front Mustang MII spindles and upper/lower Moog ball joints to begin determining the desired front-end suspension geometry. NOTE: I do not intend on using these components in the end-build, I am using them to learn right now.

"And now I bare my chest for the Archers bolt(s)"

I've decided to fabricate a wooden replica of a portion of the GT40 space frame left front chassis to work from...

... and attach the Mustang spindle to a base in order to articulate the two pieces. This allows me to work inside at 2AM without p!ssi!ng off my GF.

From what I have read some GT40 builders are going with 15 X 8 wheels for the front and 15 x 10 wheels for the rear of their cars. I am considering doing the same.

With that in mind (and assuming 15 inchers are the way to go) my next task is to determine where the 15 x 8's sit in orientation to the chassis. This will allow be to determine what will be needed as far as upper and lower a-frames are concerned (working out the geometry in particular). Of course the upper and lower a-frames must be the same distance/length from the chassis in order to allow for fluid up/down movement.

At this point "I believe" I need to choose a wheel size (height/width) for the front, grab the specifications for this wheel, and then measure back to the chassis and work out the geometry while taking into consideration the turn angle of the wheel allowing for fender/chassis clearance. I am planning on constructing the a-frames using adjustable (at least three inches) linkages.

So, am I totally high taking this approach? Is there a better method of doing this? Is there life on Mars?

I want to learn and have fun at the same time.

Many thanks Guys/Gals!

PS: Sorry about these gallery images. I could not find a way to rotate them +90

Doc Watson

Lifetime Supporter
Phew, where to start.....

Bump steer, Ackerman, camber, toe and castor.......

Ok first off, welcome to the build forum and I am already envious of your workshop space.

There are many things to consider when designing the front suspension and I have listed some of them above, if you can finalise the wooden mock up by attaching the spindle using upper and lower wishbones then you can simulated the movement of the wheel both up and down and also (if you add the steering rack) you will be able to check bump steer.

No archers bolt, a crossbowman's bolt or an archers arrow......

If you are unfamiliar with any of the terms above google them and then we can talk reverse Ackerman later (joking).

A good start and look forward to seeing more progress. Do you have a body? engine? gbox?

LOL Andy. "No archers bolt, a crossbowman's bolt or an archers arrow" is totally correct.

I have not selected the body yet. Was going to go completely with GT Forte' ... but cannot get an email response lately. Southern GT (I live in Texas)?

YesSir...the wishbones are the magic. I am wanting to determine what it is need to flesh the upper an lower out.

Since this car will be so light, I am thinking about a 351 (302 at the least) plus Audio tranny.

I do not do cars for a living. Cars are more of a hobby (I write software) and I find myself helping folks a lot with their machines.

Many thanks for your time.

Doc Watson

Lifetime Supporter
Well I teach software so most of my time is spent fixing peoples computers...... If you have ever done any 3d programming then you could write some software to simulate the geometry although the physical mock up your making will probably be the better route. Also see if you can get other GT Forte owners to discuss what they did.