I have AFR 180cc heads that are going on soon, but im still trying to piece together the valvetrain components and need some help. For cam's my choices are either the Hotcam or cc305, only cuz i have emissions. Now my problem is with the springs that came with the heads (AFR dual springs). Here are the specs: size-1.437 OD, pressure-120# @ 1.800, coil bind- 1.090, max lift- .550. I would love to keep these but im worried they wont handle the lift even with the hotcam and 1.6 rockers. I know the lt4 springs have the same max lift but still i've heard too many horror stories about ppl not using the correct springs to feel comfortable. Are there any ways to relieve pressure on the springs with lifters and NSA (non-self aligning rockers)? And if I do decide to buy some others, im wondering where to look for some that dont require machining, and how hard it is to change them? Thanks alot for your input ahead of time, and btw i'm new here and want to say hi to everyone and that this site rocks!

 

For aluminum heads the Crane 10308's will fit without machining, but they are big springs

I don't know exactly what life they are good to, but I've heard it rumored around .700... but I VERY well could be wrong. I know for sure they will work for your application though. They fit on stock LT1 Aluminum heads and LT4 heads(needed some work) that we've tried them on.

I just bought another set tonight off summit, they were lik 150 shipped. Very very stout spring though, and a real dual spring.
If you can't find an intermediate this is an option.

If you go with the hotcam, springs that goto .550 would be perfectly fine though. I also believe Combination Motorsports sells springs (CM-614 I believe) that are good to .600 lift, very easy to install, and only about 98$ shipped.

A hotcam with 1.6rrs is only .525/.525 lift, sorry I don't know the 305 off the top of my head, but if the 306 isn't that much bigger than I'd say for the 305 new springs are in order.

 

thanks for the reply eric, any other suggestions???

 

Hot Cam Springs are only good up .525 lift, so the springs you all ready have should be good for either cam.

 

IF you have a 1.800 installed height and a 1.090 coil bind allowing .100 for spring clearance you would have a max lift of .610.You could use .050 and have .660 lift.If your stated figures are correct.
The 120# number you quoted is that seat pressure,if so thats a little light for a fast ramp cam. Do you know what they are at 1.200 or max lift?The springs will loose about 10-20lbs after a few miles.

 

I dont know it just says pressure. I'm listing the numbers from the airflowresearch.com site. / tech support / valve spring specs / part number AFR-8020. That would be sweet if i could get .610 lift out of them.

 

ehh now im confused cuz there are diff numbers for silicone and chrome. maybe thats for the inner/outer spring??? here are the numbers listed below .720 ID 300# @ 1.250

 

Call AFR and see what springs you have.In MHO they are to light for the heavy work. 135# on seat and 350+#on the nose.If you don't it won't rev and make power in the upper RPM's.You will also have lifter pump up from floating the valves.99% of all cam install problems are caused by light springs and impropper valve adjustment.No you will not need aftermarket lifters with the PROPER springs and adjustment.

 

Those springs should be plenty good for a hotcam. LT4 springs give 100 lbs. of seat pressure. Hot cam with 1.6 rockers gives .525 on both valves.

 

ughhhh......so far 4 ppl say they will be fine and one said no. I give up lol. I do not want to risk things breaking or not running right. On the other hand ppl keep telling me ill be fine, AND I dont want to go thru the hassle of getting new springs that will fit, and all the other stuff, ecspecially when these are allready on the heads. Anyone else???????all opinions wanted!!!!!

 

Sounds to me that they would be fine with the HOT cam. But you need to check the installed height and coil bind, don't assume they were installed correctly.

Rich Krause