Try a 280z hood. My 240z with SBC and headers creates high engine bay temps. With a 3000 cfm fan you can feel the hot air blasting past the driver's door while sitting at a light as air exits the hood vents. Some people have installed fans under the 280z hood vents.
Update:
I have recently experimented with Carbotech AX6 pads.
See: http://forums.hybridz.org/topic/127572-carbotech-ax6-pads-for-toyota-240sx-calipers/
Ref: 1972 240Z daily driver
Brake setup:
Front: 1979 Toyota 4x4 pickup Calipers on solid 240z stock rotors
Rear: 1989 240SX calipers on 300zx non-turbo rotors
Master cylinder: 1979 15/16 280ZX
Booster: 1977 280Z
Since installing this brake system in 2009 I have been experimenting with brake pads:
Porterfield R4S: Poor cold bite in traffic. Removed after about six months to try Hawk Blues.
Hawk Blues: Poor bite at all temperatures. Removed after about one month to try Axxis ULT
Axxis/PBR ULT Ceramic: Good cold bite on first stop and in traffic. Ok in traffic and mountain driving.
Carbotech AX6: Excellent cold bite and bite gets better with each stop. After about four stops these pads grab hard.
Carbotech AX6 pads: Very little pressure on the brake pedal is required with this brake setup. I have smoked the fronts and the car hauls down fast without a hint of brake fade after several hard stops.
At this point I am leaving the Carbotech pads on.
Contact Carbotech to purchase pads: Ask for club 5% discount.
1979 Toyota 4x4 pickup: CT137-AX6 $141.00
1989 240SX: CT272-AX6 131.00
Are you assuming that the driveshaft was cut and balanced correctly?
I ask because I had a similar vibration and it turned out that the driveshaft shop welded the driveshaft off axis after they shortened it.
Suggestion: Pull the shaft and take it too a quality driveshaft shop and have it checked out.
After I got out of the Air Force, I worked in a brake shop for about a year. We would test drive the car and never bed the shoes/pads.
My Nissan dealership does our brakes. They don't bed the new pads.
Did you see these posts?
http://forums.hybridz.org/topic/118957-16-electric-fan-with-stock-shroud/ http://forums.hybridz.org/topic/108060-electric-fans/
Have you looked at Flex - A - Lite fans?
I am currently using a 3000 cfm fan and Arizona Z Car radiator to cool a SBC 350. Runs cool in traffic here in central Cal on 100 + deg days. The 3000 cfm is what made the difference.
https://www.flex-a-lite.com/electric-fans.html?cfm_range=10
http://forums.hybridz.org/topic/122990-arizona-z-cars-radiator/
Did you adjust the push rod that is between the booster and the master cylinder? If not, search the brake forum for "push rod adjustment".
It is a common oversight when installing the ZX master cylinder.
If the push rod is too long the return port in the MC will be blocked which after a few stops will lock up the brakes. You can relieve the fluid pressure by opening the MC bleed screws so carry a wrench with you when testing the push rod adjustments.
You don't have to remove the MC from the car. Leave the brake lines attached and just remove the two nuts holding the MC to the booster. Pull the MC away from the booster and push it to the side.
Note: when adjusting the push rod be careful not to drop the reaction disk inside the booster. Try to minimize pulling on the push rod.
Welcome.
A bit more information is required:
Is the wiring stock or after market?
What modifications have been made to the stock wiring?
Do you have the Factory Service Manual (FSM) for your 240Z? You will need it.
Have you downloaded schematics for your car?
Have you searched HybridZ for posts related to turn signal problems? There are many posts that include "how-to" videos.
Have you searched Google or YouTube? There are many "how to repair turn signals" tutorials and videos for the 240Z.