cam change?

[sleekvino]

whats the stock spring pressure of a bbc oval port heads and could i put this cam in with out changing springs.
Chevrolet BB 280AH Marine Cam
Part Number: 11-314-4
Manufacturer: Competition Cams
Comp Cams High Energy 280AH hydraulic Marine camshaft for Chevrolet BB 396-427-454. Jet boat with A impeller. Skiing, pleasure use, & performance.
Specs are as follows:
280/288 Advertised Duration
Duration @ .050" 232/237
Valve lift .547/.547 with 1.7 rocker ratio
Lobe seperation angle 110 degrees
RPM operating range 2400-6400
thanks :notam: .

[steelcomp]

Don't know stock spring pressures on those heads, but you definately won't have any success running them. Best to go with what Comp recommends for that cam.

[396_WAYS_TO_SPIT]

thats a nice cam., I always recommend using the matching springs for the cam just to be safe. Remember stock is stock!

[SmokinLowriderSS]

The problem is rarely spring pressures, it's coil bind from trying to open valves farther than the springs are able to compress. When all the coils close together, you no longer have a spring, you have a soilid bushing. Fastest way I know of to wreck lifters is bind the springs. I also advise using the cam-maker's reccomended springs, rarely have trouble then.

[steelcomp]

The problem is rarely spring pressures, it's coil bind from trying to open valves farther than the springs are able to compress. When all the coils close together, you no longer have a spring, you have a soilid bushing. Fastest way I know of to wreck lifters is bind the springs. I also advise using the cam-maker's reccomended springs, rarely have trouble then.
SLSS...in this case, it's going to be both pressure and cb. Anything over about 218-220 deg. @ .05 with more than .500 lift, you're running into lobe profiles that need to be more carefully followed. It's not radical, by any means, but you'd like to see at least 95-100 lbs. seat pressure. That cam I'd like to see 110 on the seat. Other than L88 springs, I don't know if there are any stock springs that will get you there. You're right about cb, as well.
Sleek...be sure to check retainer to guide clearance, as well.
What rockers are you running?
If you haven't bought the cam yet, you might think about the complete K kit.
K11-314-4 That has cam, lifters, timing set, springs, retainers, locks and seals. Or, you can just get the springs and retainers. Springs are either 911's which are single with dampener, or 924's which are a dual w/ dampener. Steel retainers for both are the 741's, and 612's are the keepers. :coffeycup

[GUGS102]

I've got the matching springs with only 25 minutes on them for the comp 280 cam. I also have 1.88/2.19 stainless valves to match. They both only have 25 minutes of break in time. We opted to go with a complete roller set up which dictated longer valve stems and different springs.
Check to see where the valve guide sits on your heads, you may have to machine the valve guides in order to clear with that lift. I'm running O49 oval ports on mine with a 246/246 .622 roller now.
If interested I'll sell the whole shot for $125. Let me know.
Thanks,
Gugs

[SmokinLowriderSS]

Quite true Steelcomp. I didn't intend to minimize the need for suficient spring closing force to actually FOLLOW the cam and get the valves to close. Floating a valve is every bit as bad (and far more destructive usually) than coil bind. At least the CB will kill lifters and maybe a cam, Floating a valve and having an impact will tear up a LOT more parts, all of them expensive. :jawdrop: :jawdrop: :mad: :mad:
Thus the reason I advise getting a full kit setup together, should avoid both problems.
I'm running an Isky cam I got from DuaneHTP, very happy. .565 lift, 280* dur, Kit had cam, superlifters (guaranteed no-pump-up till 7-grand), 3-part springs, retainers (steel), shims, polylocks. All I needed were rockers (I had old short-slots), seals and a machinist (to fit the small seals). Have about 15 hours on her, running solid as a rock.

[SmokinLowriderSS]

[QUOTE=GUGS102]I've got the matching springs with only 25 minutes on them for the comp 280 cam. I also have 1.88/2.19 stainless valves to match. They both only have 25 minutes of break in time. We opted to go with a complete roller set up which dictated longer valve stems and different springs.
Check to see where the valve guide sits on your heads, you may have to machine the valve guides in order to clear with that lift. I'm running O49 oval ports on mine with a 246/246 .622 roller now.
If interested I'll sell the whole shot for $125. Let me know.
Thanks,
Gugs[/QUOTE
Looks like a heck of a fair deal from GUGS102. My kit setup was $400. I had no interference issues on my large oval-port heads at .565" lift but they do get close. be sure to check yours carefully.
If he has the springs with 2 springs and a dampener, you will at least have to have machining dome to fit small-dia seals on ( I had to).