We know a lot of OneDirt nation races crate engines, and while there is usually very little that can be done to the engines legally, we are always on the lookout to help you race better and have more fun at the track.
And the new valvesprings Chevrolet Performance has available for it’s popular CT400–also known as the “604”–crate race engine may be exactly what you are looking for. These new valvesprings won’t magically give you an extra 50 horsepower (Chevrolet says they make no change to the horsepower and torque ratings) but they are a real improvement over the original springs in several areas. So we wanted to take a closer look to help you decide if they are worth investing in for your next rebuild.
The new valvesprings are a beehive design, so they will also require new, smaller retainers. Chevrolet Performance sells them in a kit (part number 19300952) with sixteen each of springs, retainers, locks and seats. Street price is 360 bucks.
Granted, that is quite a bit more than a set of the original springs for the 604, which normally go for around 50 bucks, but those springs varied so greatly that teams normally buy a dozen sets or more and rate each spring individually trying to find two or three well matched sets of 16. Plus, those original springs are also notorious for losing pressure very quickly.
These new springs should be able to maintain proper spring pressure longer because Chevrolet even says for themselves that they are a higher quality. By making the top of the spring smaller, the beehive shape moves the greater stresses lower on the spring where the coils don’t see as much vertical movement. Another clue is the fact that these beehives utilize an oval-shaped wire to maximize valve travel before the spring goes into coil bind. This is important because in the manufacturing process, properly coiling an oval wire into a spring requires both greater control and a higher quality raw material for the wire. Chevrolet also says that, “The oval/multi-arc wire shape places the maximum area of the wire at the point of highest stress to handle valve train stress more efficiently and allow better heat dissipation for longer life.”
To find out more details we stopped by the shops of KT Engine Development in Concord, NC, while they were rebuilding a 604 crate. KT Engines is an approved rebuilder of these sealed crate engines for a handful of racing series, and as part of this particular rebuild they were installing the new spring kit. Engine builder Ken Troutman says, like Chevrolet, he hasn’t seen much of a difference in the power levels of engines with the new springs on the dyno, but he does believe the higher quality spring results in fewer broken springs–and ruined nights–at the race track.