valve spring?

[fst3rdgen]

Im having a problem with RPM, and thought this would be a good place to ask some ?s. Im running a blow thru F-2 on my 406sbc, AFR 227s, cam is a 265/275 dur. .630 lift, valve springs test out at 210#seat and 550#s open. With the same cam/vs combo and a fogger last year I could not shift the car fast enough. Last month had the car on the dyno and would go to 6500rpm and then hit a wall, it has unbeleavable amount of power down low but just dosnt seam to pull on the top it has still ran my 3500# car 8.58 @ 162. Im thinking that I may not have enough spring to hold back 25#s of boost. The only reason I have not changed springs is I know I need a better cam, and I would want to match the spring to it. The next problem is that Im running a comp steel roller rocker and a 7/16 stud witch worries me about putting the spring press I know I need to run without messing that up. I need to do some other upgrades in different areas before I can afford to go with a complete valve train upgrade I would be greatful for any help Thanks

[Zeke1]

Its all springs, you run 25 PSI (pounds per square inch) now figure out your intake valve square inch and mutiply by 25 you will find you have very little pressure around 150, and if it was me I would be running about 300 to 325 on the seat, and you better fix it now before you drop a valve if its stoping at 6500 rpm I would bet its floating the valves around 4500 to 5000.

And don't worry about the 7/16 studs if they are ARP and steel rockers they should be fine as long as you have a stud girdle but a shaft system would be best.

[Jay Allen]

The RPM range sounds low enough the load (in PSI) should not be an issue.

Good post Zeke.

[fst3rdgen]

Thank you for the answers.

My next ? would be were should I be for a open press, and will a Herberts cam be a issue with the pressures. Its going to be a coulpe of months before I have the $$$ for a new cam and this one is showing its age. Jay you did some grinds for a couple of freinds both in Idaho falls ID one with almost the same setup, Would I be good to run the crower sping they both are running so I dont have to change when I go with one of your cams? Thanks

[Jay Allen]

Would I be good to run the crower sping they both are running so I dont have to change when I go with one of your cams? Thanks
The blower car and the turbo car. yes, yes, yes.

Those Crower springs kick ass. However I have been told lately they are discontinued. I have been recommending a Manley 22440-16 on applications (+/-) .700" and MUST run a 1.550" spring.

I'll be though that the cam core you have is NOT going to take what you want to do. That'll lead to a failure. I am all for buying a part (1) time and saving ca$h. But on this I just don't know.......I wouldn't run that good of spring on that core.