The LS1 shorty headers are designed to fit into the 1970-1978 Datsun Z cars using the LS1 engine.
These headers will work with the John's Car LS1 mounts.
The primary tubes are 1-3/4" and the collectors are 3".
The fit on the driver's side is very tight. The header on the driver's side requires trimming one of the bosses on the engine block. The header on the driver's side must be installed from underneath the car.
The spark plug wires need to be changed to 90 degree boots. 90 degree boots are used on LS2 engines.