What chips are available for my truck?
For aftermarket chips. ATR is ok if you run stock boost. But a 3bar chip is better.

What is a 3Bar chip?
A 3Bar chip allows the ECM to read and tune for up to 30psi, instead of the stock 2Bar which only reads 15psi.

Do I have to do anything special to run a 3Bar chip?
Yes, you will need a 3Bar MAP sensor from an 89 Turbo Trans AM. GM part #16040749

What size is the spare tire on a Syclone?
Firehawk FTX 225 60-15

What size is the spare tire on a Typhoon?
16X4 T145/80R16

What are the specs of Syty Rims?
Bolt Pattern - 5x4.75 in. or 5x120.65mm.
Stock rim - 16x8.
Stock Offsets - 41mm. front, 13mm. rear.
Front wheel offset inboard 1.75 inches, backspace 6.25 inches
Rear wheel offset inboard 0.66 inches, backspace 5.16 inches

What are the specs of other rims that fit SyTy's?
ZR1 Sizes are:
17x9.5 - 56mm offset/7.4 backspacing - Front, for 88-96 Corvette -
17x9.5 - 38mm/6.7 backspacing - Back, for 84-87 Corvette 
17x11 - 50mm/7.93 backspacing, Back, for 88-96 Corvette. Fits perfect, no spacers needed.

What number Syclone or Typhoon do I own?
Syclones - Last 4 of the VIN is the # truck you have.
Typhoons - Last 4 aren't production #'s but the SyTy community has accepted them as truck numbers


What spark plugs should I use?

AC Delco part Number CR42TS gapped to .032-.035. It must be this number. R42TS or CR43TS are not the correct ones.

Are there any other plugs that I can use?
Yes. NGK UR6-stock & TR6-Vortec heads.  UR5 are the stock heat range, UR6 is colder.  Same with TR5 and TR6.  Running the 6 heat range instead of the 5 won't hurt anything, and it could help.  Many people are swearing the NGK plugs run better than the AC plugs, Chitownsyty is of the same opinion.

What should my timing be set at? and is there anything special I have to do to check it?
Zero degrees, there is a brown wire under the carpet where the passengers foot would rest, disconnect it to check for zero degrees. You will set a code by doing this, so make sure after you verify the timing that you reconnect the brown wire and unplug the ECM fuse to reset the ECM's stored codes.  Doing a Top Dead Center check is a good thing. This verifies that your balancer readings are accurate, as the balancer ring can spin, giving values that are not accurate, making timing verifications worthless. This is crucial, because if a truck is running advanced timing, it will detonate and cause engine damage.

What cap and rotor do I use?
Conrad cap and rotor #DR2012G (AutoZone carries them).  Accel cap & rotors have caused problems. NAPA also sells a good brass contact cap & rotor.

What are the best wires to use?
Chitown guys have had the best luck with Taylor spiro pros.  KB uses Taylor wires.  ATR don't seem to stand up to heat.  MSD boots seem to melt.  Magnecor sometimes cause problems.

My Tach keeps fluttering What causes this?
Telltale Ignition problems. Do tune up with the above listed products.

What coil should I use?
Accel coils have caused problems in most trucks. MSD coils have a tendency to burn out rotors.  Some are using Crane coils with success.  Chitownsyty opinion:  Use the stock coil, it has powered trucks to the 10 second level.


Is there an upgraded Fuel Pump that I should buy?
Yes, Walbro 255 LPH High Pressure from Ron Gregory's Website. Good to ~600hp.  This is cheap insurance, and it is of Chitownsyty's opinion that it should be installed on any truck.

Is the 7th injector from ATR any good?
Not for our applications. It is better to install bigger Injectors.  The 7th injector may cause fuel distribution issues, as it injects fuel at the throttle body, and the stock injectors are located at the intake ports.

Can I use an inline fuel pump?
Sure, but we don't advise it.  They usually cost more than a good intank pump, and you are then relying upon 2 pumps to work.  If one goes, you generally wouldn't find out until you are at WOT (wide open throttle).  The biggest issue is that if you have an upgrade intank pump that dies, your truck won't start, if you have 2 pumps and one dies, you can kill a motor by going lean at WOT.  Play it safe, go with the intank pump, it is cheap.

What is base Fuel Pressure?
Base is read by removing and plugging the vacuum line hooked to the Fuel Pressure Regulator.  You can do this without having to start the truck. There is a fuel pump relay at the firewall, behind the intake. It has a grey wire with a small terminal, hanging down about 3" off the relay. If you put 12 volts to that wire, the fuel pump will energize.  You can use a short wire to do this, as there is a 12 volt source junction on the firewall to the left of the fuel pump relay.  

How do I adjust my fuel pressure?

You will need an adjustable one from either ATR, Kenne Bell or Tony DeQuick. Their are others out there too. 

What should my base fuel pressure be set to?
2 Bar MAP sensor - base of 45psi
3 Bar MAP sensor - base of 50psi

What is the difference between a 2 and 3 Bar MAP sensor?
2 Bar MAP sensor - Reads up to 15psi
3 Bar MAP sensor - Reads up to 30psi


Are the replacement 4.3L's that the dealers are installing the same as the syty's?
No, it seems most dealers are clueless as to what a Syty motor is.  Most are giving out stock 4.3 motors for that era. The problems are:  They lack the correct low compression pistons, they usually use higher flowing L35 heads (by itself not a bad thing), they don't contain the correct nodular iron main caps, and they are usually remanufactured engines. The Remanufactured engines that I have seen used are of poor quality.  Of the 5-10 I've heard of being used, I believe 7-8 suffered massive bearing failures, with the dealerships blaming owners for breakdown.

What rods and pistons should I use in my new engine?
L35 rods (from 93 & newer W code engine) are stronger than stock and a good choice for a very budget rebuild.  If you are planning on any racing, Eagle rods are the best bang for the buck.  They will require oil pan clearancing, which can be done with a torch and a hammer. Pistons - TRW make a piston for small block Chevy's that works great for 4.3 buildups on a budget. LF2441.  They lower compression slightly, and are forged.  If you are building something for higher performance, J&E, Wiseco or Diamond are good pistons to use.

Sometimes when I start the truck I hear a clicking noise and it won't start. What is this? How can I fix it?
That is called "starter click". The starter solenoid engages but doesn't spin. This is very common in S-Series trucks. Replace the Purple wire that connects to the solenoid with a thicker gauge and for extra protection put heat shielding around it.


What is the stock stall speed of torque converter?
about 2100

Is there an upgraded converter that I can get?
Yes, 9/11 from ??? info please.

Turbo and Wastegate


My stock I/C pump is dead is there a replacement?
Yes, The Jabsco is a direct replacement or a Shurflo can be installed with some modification. Click here to see the install.


Who makes rear sway bars for SyTy's?
Suspension Techniques (can be ordered from, Addco or ATR

My front end is shot. Where can I get new bushings?
PST or Energy Suspension