I have chrome valve covers with oil dripper rails. What type of rockers will fit under these? The heads have big valves and 347lbs/in. Dual springs. Sent from my iPhone using H.A.M.B.
What typically causes the interference is use of poly locks on the rocker stud. Or of course a stud girdle if you get more serious. Even full roller rockers are not a lot higher than the stock stamped ball rockers. It is the poly locks that lock down the nut that tend to cause the interference. Unless your springs are substantially taller than stock, and corresponding longer pushrods, that will raise the entire rocker assy higher up. Valve diam has nothing to do with it, but installed height of the valve stem and spring does.
Do the old M/T valve cover work with the stud girdle? I’m trying to figure out where to put my money. Sent from my iPhone using H.A.M.B.
Given the sticker on it, I wonder if they are higher than stock Chevrolet automotive valve covers? Sticker says only av-gas or racing gas to be used, maybe already higher for a marine performance application
thats an interesting picture, the call for high octane is odd, as that is a low performance marine motor with a quaddrajet carb, which should be low compression with oval port heads and a two bolt main from the small oil galley plug above the filter, wonder if merc back in the day thru some 11-1 pistons in some of their low perf motors for marine use? anyhow, u will clear a roller tip rocker no problem...roller rockers take double stacking the gasket and short poly locks....cool motor, whats the casting date and number on it?
the old finned tall M/T covers cleared Crane Gold rockers and stud girdle. Valve cover spacers work. I was hiding a tall deck 482 big block with intake spacers and valve cover spacers and painted it all Chevy orange and under the parking lot lights it passed off as a 396. Made a bunch of money with that motor.
To answer the question only stamped rockers and nuts will fit under those valve covers with the drippers. I have used Harlen Sharps with stock valve covers without the drippers.
Those are junk 425HP marine valve covers that I bought for $20. But I like them, they have the dripper rails, and multiple spots for breathers and caps. The AC delco breather is original. I basically needed them for mocking up my engine. It’s a Truck 454 with forged crank and 781 heads. Heads and crank are off getting machine work. Block is next. Sent from my iPhone using H.A.M.B.
M/T with oil drippers removed will clear roller rockers but not a stud girdle. You would need to add the spacer for that.
I run comp roller tip, ball pivot rockers on a couple of mine...they seem to work ok with a hydraulic roller cam under .600 lift, and dual springs designed for the cam. I don't remember the #/" number, and I'm on the road so it's not easy to look up right now.
I have the isky z-55 cam and Comp cams 294s being recommended to me from 2 different builders. Those cams are under .600 lift I’m considering a chromoly roller tip rocker. I’d like to keep stock valve cover and put my money towards carbs and intake. I’m looking at 2 660 or a big 950 Holley. I will end up tuning the engine on the builders dyno. Maybe we will try a tunnel ram and a victor jr. and see what the engine likes. Sent from my iPhone using H.A.M.B.
There had to be some sort of L88 marine engine back in then. I will ask the engine builder next time I see him. Sent from my iPhone using H.A.M.B.
10-4, looked like a mid 70s gm factory mill to me except for the covers....lol.....heck I ran a 595/635 lift isky z-90 flat tappet under stock covers on my ratt with stock stamped rocker arms back on the street in my 69 chevelle in the early 90s, car flat out ripped, for back in the time, ran 124mph in the quarter on old slicks, had more fun with that chevelle then any other car, it eventually split a rocker arm, oh the crazy things we do when we were young!..
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