I have put about a 1,000 miles on my GT40 now. I thought I would share some driving impressions on the car. I built mine to be a road car so that is the perspective I am writing from.
The car is extremely fast and well mannered. My engine is less than 400HP. I am not comfortable enough with the car to really push it hard, but if you give it gas at 60 you are at double the speed limit pretty quickly. I have not tried to launch the car, but I am sure that there is more than enough power to make it challenging to keep the car hooked up.
The ride is not too harsh except for hitting big bumps like a bad bridge expansion joint. I don't know if it is the shocks or the rose jointed suspension but it make a pretty big bang when hitting bad bumps. Otherwise the ride is quite good. It rides very smooth on most road surfaces.
The car corners well. I believe that my cornering is limited more by my tires than anything else. I am running the older BFG TAs on 15" rims. Choices are a little limited for the 15" rimes. The tires are not great for performance but do have a period look. They start to protest as you approach the limit of traction so there is plenty of warning before you start to slide. There is very little body roll in turns. I do not have roll bars and I do not see any point in adding them for street use given how little body roll there is.
The steering is very light in parking lots. The rack ratio seems an excellent compromise between speed and turning effort. (My rack is attached at the outer or slow connection on the front spindles.) The turning radius is bigger than I am used to. It is a little bigger than my extended cab truck. It takes a little getting used to. I have found myself close to the curb on a few tight corners. East Tennessee has some extremely narrow roads that force you to plan ahead if you drive something with a large turning radius. This is a pretty reasonable compromise to have the extra foot well room that this provides.
I have not really stressed the brakes much yet. I did do one sudden stop in traffic and got reminded that I needed to spend more time on my brake bias. I have since shifted the bias more to the front but have not tested it much. I do need to have the rotors turned. There is a slight run out on them that I can feel on the pedal.
I am running an Audi 5N transaxle. First gear is nearly worthless unless you are starting on a steep hill. Fifth gear is not bad for highway speeds. I am running about 2500 RPM at 60. I may do a ring and pinion later to lower the RPMs a little and make first gear more usable, but that is for a later day. Shifting it into reverse is a challenge. Between the lock out on the cable shifter and the built in interlock built into the transaxle it is tough to get it into gear. I need to play with that a little more. I am sure I can do something to make it better.
I am happy with the engine I built. It is a 302 with 10.5:1 compression, AFR 165 heads, Performer RPM intake, Holley DP carb, roller lifters and rockers, cross over exhaust, and a Comp XE276HR cam (about .54 lift and 224/230 duration). The motor has an incredible sound to it through those pipes. It also is pretty well mannered for the size of the cam. I have had some issues with the Holley carb, but otherwise the engine has been great.
Driving in traffic is interesting. Looking up at subcompact cars is odd. Looking up at a jacked up SUV is unnerving. Changing lanes was too difficult with stock mirrors. I bought a pair of convex mirrors at Walmart that I mounted on the door window sill (inside the glass). They covered the blind spots perfectly. If I can see a car in the flat side view mirror but not my convex mirror I have room to change lanes. With that addition I am very comfortable tangling with the morning commute (yes, I drive it to work).
The car draws an incredible amount of attention. I have owned a number of unique cars including a '56 T'Bird and a Cobra replica. They drew attention but this car draws considerably more. I frequently see people driving with their cell phones out the window taking pictures of my car from the adjacent lane as we travel down the highway. Gas stops and other errands always draw a crowd.
I have reached the point where I have worked enough of the bugs out of the car to be comfortable driving it. I am really enjoying it now that I am not worried about the usual sorting out issues. I am nearly ready to take it for a longer trip to see how it does.
