GSKs use stiffer springs to delay the expantion of the counter weights in the governor. This effectively delays the rpm that the governor begins to defuel at.
Basically it not only lets you rev higher, but the truck will continue to pull hark until 3k or 4k before it defuels and loses power like stock does at 2500-2700.
The only diffference between the two is two $7 small springs. If you get a 4k and only want 3k rpm just leave the springs out and if you ever want a 4k just put them in. If you plan on exceding 3300rpm 60lb valve springs would be a good idea to put on the exhaust valves. If you don't the valves may float and contact the pistons
Basically it not only lets you rev higher, but the truck will continue to pull hark until 3k or 4k before it defuels and loses power like stock does at 2500-2700.
The only diffference between the two is two $7 small springs. If you get a 4k and only want 3k rpm just leave the springs out and if you ever want a 4k just put them in. If you plan on exceding 3300rpm 60lb valve springs would be a good idea to put on the exhaust valves. If you don't the valves may float and contact the pistons
