Stage 1 GT-5 Top End Kit 66cc:
This Stage 1 Engine Kit provides turnkey performance for your GT-5 motor. Buy the whole top end kit and get the original Fred Head for free ($10.00 extra for slant head). This american designed and manufactured cylinder head has many copycats trying to get a free ride from Fred's hard work. Buying from CR Machine will help keep an American machinist at work. Thank you! The cylinder body in this kit is fully and beautifully ported and polished for optimal flow and timing characteristics. Exhaust port timing is designed for tuned expansion chamber exhaust systems. If you plan to use a stock exhaust system, let Fred know this, so he can tailor the port timing to work with that type of exhaust.
- Your choice of single ignition head, with extra tall nuts. *see note below.
- 1 Modified cylinder body with stock intake
- 1 Modified GT-5 (Type-B) piston with rings
- 1 Wrist pin set
- 1 aluminum head gasket
- 1 high quality base gasket
- 1 Exhaust port gasket
- 1 NGK spark plug
*For engines using a stock or mildly advanced exhaust system, the 5.0 or 5.5 cc head is a good choice, unless you plan to use race fuel. If you plan to run race fuel, then the 5.0 or 5.5 cc head will be excellent for highly advanced motors. For engines with an advanced exhaust system and using normal pump fuel, use the 6.0 or 7.0 cc head. There are other heads that can be substituted. Contact Fred and explain your engine configuration. The price will be higher for slant head or twin ignition head types.
*There are two GT-5 type engine manufacturers that we have seen: Some GT-5 type engines use fine thread cylinder studs. These engines use the "FM 80" connecting rod. The other known GT-5 type engine uses coarse threads for the cylinder studs. These engines use the "ZAF 80" connecting rod.
Coarse thread cylinder head nut torque spec: 60 inch pounds
Fine thread cylinder head nut torque spec: 48 inch pounds
- Before fitting the spark plug, gently rotate the engine to verify that the piston does not hit the cylinder head or the crankshaft.