383ss

iTrader: (14)

I swapped from a 2.02 to a 2.08 valve on a 1.78 install height and am now gettting valve float with Manley dual springs. I'm sure this is because of the extra valve weight. the springs still test just fine at 385 open pressure at .650 lift and 140 seat pressure. my pockets are also already cut for 1.46 OD springs if needed. I need a spring that will give me around 450lbs at .650 lift. are there any out there??

I'm considering PRC springs, but am not sure if they are enough. it will give about 20lbs more pressure throughout the lift. any ideas?

cam is a FMS 253/261 .642/.622, lifters are stock replacement mellings.

TAQuickness

iTrader: (28)

I don't know the partnumber off the top of my head, but Comp makes a nice sized behive (look in the BBC area of the catalog) that should meet or exceed your needs

kumar75150

uh oh

i have the same cam and same springs and 2.08 valves

my car is being put back together right now

383ss

iTrader: (14)

the problem is I can't have TOO Much pressure. it will collapse the OE replacement lifters.

I may not have my problem nailed down. its possible its not the springs, but I'm not sure what else it could be.... nothing else on the car has changed besides adding an FTRA

Viper

iTrader: (6)

At this stage of the ballgame, buy better lifters so you're not riding the edge on them anyway IMHO. Check out the "what springs on AFR's" thread , the Morels are up to the task.

PortPros1

Assuming you have a hydraulic roller cam, your closed spring pressure is good, your open is to much. More than likely your collapsing the lifter at high rpm.
Are you lifting the valve .650? I would think about Comp Cams R-lifters they will take more pressure and higher rpm. I also like the Comp Cams bee-hive springs we run them on all of our LS1 and Viper heads, very good spring.
Give me a call or e-mail, advise is free. I'd be happy to help. PortPros@sbcglobal.net (512) 257-0222 www.Portpros.com

383ss

iTrader: (14)

yes, it is a hydraulic roller cam. I may give you a call. thanks for the offer

after looking again and overlaying dyno's, power is down everywhere. losing about 20-30rwhp/tq. Initially I guess I was just looking at the high RPM area and jumping to conclusions

I think I'm looking in the wrong place, but I have no idea where to look next. did a quick compression test and everything was ok there. all rockers were tq'd correctly too.