I was looking over various Crane FE cams, and it seems they no longer recommend the 99837 springs for all their FE cams. For the cams I looked at, including the one I'm using in my 390, they now recommend stiffer springs.

Here's the spring recommendations I found:
Crane 901: 96801
Crane 941: 96801
Crane 521: 99896
Crane 541: 99896

Here's the specs for those two springs:
99837: 106# @ 1.8", 280# @ 1.25", 320lbs/in rate
96801: 114# @ 1.8", 266# @ 1.3", 310lbs/in rate
99896: 150# @ 1.9", 560# @ 1.15", 528lbs/in rate <-- This is a dual valve spring.

Greg should find this interesting...

 

Guys, it is about time. I have always wondered how Crane ever came up with some of the spring recommendations that they previously had. Looks good so far, after those guys running juice rollers complained for the last two or three years. Better late than never, I suppose. I think the 99896s may be just a bit heavy for the '521 hydra-roller, but too much is better than not enough when it comes to valvespringing. DF, @ work

 

I agree its about time fixed up there info. They having working on it for over a month.

Hey, Kurt I redid some of my calcualtions for rpm range. Looks like my max rpm was around 5691 for the 99837 springs at 1.785-1.805 installed height.

1st gear 57mph 5691 (all she wrote)
2nd gear 85mph 5038 (all I have taken it so far)
3rd?

I promise I will be getting a new tach in the next two weeks.

 

Be sure that you do. I'd bet your power tapers off after about 5000rpm.

 

you are right Kurt, I know its falls off after 5000. 4500 to 5000 is not much of increase in power. when looking for max accel i would idealy shift around 4500 as the torque is falling off and the peak horsepower is close.

4500 377hp 440tq
5000 385hp 405tq


I think the 99837 springs are weak, the 91 lbs at 1.800 is a little off the 106 that crane says but the spring are suitable to 5300-5700 rpm I guess. I don't know if your cam would allow the motor to turn more rpm or not. You are probally not a ******* like me.

 

Well, if ******* means chicken, then yes, I'm there!

I haven't even tried manually shifting mine yet. In drive it shifts somewhere between 4500 and 4900. But it's still building power. I'm just afraid of going to far, finding neutral, and blowing the thing up.