When it comes time to freshening up the heads, what is recommended on this motor? I currently have a whipple stage 3 kit and roughly 160 hours. Any info would be appreciated.
We would recommend Isky springs and better locks and retainers, as well as our platinum rockers for the extra RPM of the whipple upgrade.... We have the cometic head gaskets that are appropriate for the 525/600/700 as well... This would be to make as much power as you do now, but with better reliability at high RPM. This would be about $2500 in parts, gaskets, and head machining if you give me the heads off the engine.
If you find yourself going above 5400 RPM, it doesnt matter how much time the engine has. You need to upgrade the valvetrain to avoid potential disaster.
If you are looking for even more power, we can CNC port the heads, install 11/32 guides, and change the cam, along with fresh valves and springs like above.... That will get you 875 HP and 6200 RPM.
John Teague
With the whipple upgrade I believe im roughly at 800 maybe a little more HP. What is the cost on maching the heads and installing the cam? With the added HP but taller rev limiter, would I be able to spin the same prop. Lets be honest here, them cleavers aint cheap!
While its on my mind. I know the stock NXT's transmission can be the weak link in the system. With all the added power, how does the trans hold up?
You are correct. The NXT "transmission" aka cone clutch in a box becomes the weak link at that power level. However, it takes more power to turn a hydraulic transmission... so the cone clutch box is actually the fastest setup.
The CNC job and program and cam will be about a $2K additional above the regular head rebuild.... But yes you should be able to keep the prop and just turn it further with RPM.
JT
So would you need the whole engine at this point or do you have recommended installers (Havasu) for this upgrade?
When do the NXT trans tend to fail? Is it the higher RPM or just the added power at any RPM level? Is there upgrades for the stock trans and when do you recommend having them rebuilt?