Stamped rockers BBC - Chevelle Tech
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post #1 of 43 (permalink) Old Feb 15th, 20, 2:16 AM Thread Starter
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Stamped rockers BBC

Is there a way meassure If the slot is long enough for the cam lift?
Have a set of stamped BBC rockers I would like to use with a flat tappet cam .550 lift
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post #2 of 43 (permalink) Old Feb 15th, 20, 8:09 AM
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Re: Stamped rockers BBC

Maybe call Summit and ask how long the slot is on the Crane long slot stamped rockers? I have a .533 lift cam in my 454 that was fine with 1986 RV stamped rockers, I can measure a couple of them later today, it has 69 063 heads & stamped rockers on it now or Id measure the 69 rockers too...if they're even the original stamped rockers?
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post #3 of 43 (permalink) Old Feb 15th, 20, 8:14 AM Thread Starter
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Re: Stamped rockers BBC

Quote:
Originally Posted by shovelrick View Post
Maybe call Summit and ask how long the slot is on the Crane long slot stamped rockers? I have a .533 lift cam in my 454 that was fine with 1986 RV stamped rockers, I can measure a couple of them later today, it has 69 063 heads & stamped rockers on it now or Id measure the 69 rockers too...if they're even the original stamped rockers?
That would be supernice of you to do that!
Maybe a picture of the rockers too?
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post #4 of 43 (permalink) Old Feb 15th, 20, 9:19 AM
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Re: Stamped rockers BBC

The rough test was put one on and see if you could get a paper clip between the rocker and the stud at full lift.
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post #5 of 43 (permalink) Old Feb 15th, 20, 11:11 AM
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Re: Stamped rockers BBC

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Originally Posted by Chevelle 1969 View Post
Is there a way meassure If the slot is long enough for the cam lift?
Have a set of stamped BBC rockers I would like to use with a flat tappet cam .550 lift
I bought the Summit steel rockers for a BBC last year and they have a ton of clearance for cams up to .600, they were also made in the USA.
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post #6 of 43 (permalink) Old Feb 15th, 20, 11:38 AM
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Re: Stamped rockers BBC

Not trying to sway you,but when I changed nothing else on my HO454 crate motor except for those stamped rockers it came with,it was a huge seat of the pants difference.Felt like I put a bigger cam in.
I use the comp ultra pro mags,not cheap,but I love them.
The gen 6 crate motors use stamps which would prolly be more than good for what youre doing.
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post #7 of 43 (permalink) Old Feb 15th, 20, 12:32 PM
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Originally Posted by 72LS3Z27 View Post
Not trying to sway you,but when I changed nothing else on my HO454 crate motor except for those stamped rockers it came with,it was a huge seat of the pants difference.Felt like I put a bigger cam in.
I use the comp ultra pro mags,not cheap,but I love them.
The gen 6 crate motors use stamps which would prolly be more than good for what youre doing.
Interesting !
Could factory rockers have been mid-adjusted ?
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post #8 of 43 (permalink) Old Feb 15th, 20, 12:36 PM
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Re: Stamped rockers BBC

Quote:
Originally Posted by Reelysalty View Post
Interesting !
Could factory rockers have been mid-adjusted ?
They just bolt down in stock form on a gen6.

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post #9 of 43 (permalink) Old Feb 15th, 20, 1:09 PM
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Quote:
Originally Posted by 72LS3Z27 View Post
Quote:
Originally Posted by Reelysalty View Post
Interesting !
Could factory rockers have been mid-adjusted ?
They just bolt down in stock form on a gen6.
You folks with your modern motors. !

😁
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post #10 of 43 (permalink) Old Feb 16th, 20, 11:29 AM Thread Starter
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Re: Stamped rockers BBC

Quote:
Originally Posted by 72LS3Z27 View Post
Not trying to sway you,but when I changed nothing else on my HO454 crate motor except for those stamped rockers it came with,it was a huge seat of the pants difference.Felt like I put a bigger cam in.
I use the comp ultra pro mags,not cheap,but I love them.
The gen 6 crate motors use stamps which would prolly be more than good for what youre doing.
Do you still have the stamped rockers? Maybe you can meassure the slot? The ho cam is .510 .540?

Quote:
Originally Posted by 68Chevele View Post
I bought the Summit steel rockers for a BBC last year and they have a ton of clearance for cams up to .600, they were also made in the USA.
Thats my backup plan the rockers I have are almost new so hoped I could use them

Quote:
Originally Posted by shovelrick View Post
Maybe call Summit and ask how long the slot is on the Crane long slot stamped rockers? I have a .533 lift cam in my 454 that was fine with 1986 RV stamped rockers, I can measure a couple of them later today, it has 69 063 heads & stamped rockers on it now or Id measure the 69 rockers too...if they're even the original stamped rockers?
I measured mine just under .700
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post #11 of 43 (permalink) Old Feb 16th, 20, 12:14 PM
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Re: Stamped rockers BBC

My experience going from stamped to roller on a 350. If you adjust hydraulics running this is what happened. Engine was warm. Backed off one rocker until clicking, moved to 0 lash and quickly moved tighter 1 full turn. engine rpm stumbled. Installed a roller on the adjacent cylinder exhaust and did the same thing, no stumble at all. There is a ton of friction in the fulcrum of a stamped rocker, but they are reliable. Today's rollers on the other hand are suspect to failure. I had 1 stamped break years ago but never a roller from the past made in U.S.A. fail. But sometimes at the track the announcer will ask if anyone has an available roller. I'll stick with solid flat tappets.
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post #12 of 43 (permalink) Old Feb 16th, 20, 7:48 PM
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Re: Stamped rockers BBC

SH!T I've been working on blah blah forgot to measure/take pics, apologies, going over to the shop now


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post #13 of 43 (permalink) Old Feb 16th, 20, 8:29 PM
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Re: Stamped rockers BBC

Here's 1 of my 86 RV rockers, sorry so late
edit: I ran these for a very short time with a .533 lift cam and I just noticed some "hard" marks at the PR cup & the slide of the rocker but I don't know if that's normal or not, came from an RV engine that had less than .500 lift (.470ish) originally
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post #14 of 43 (permalink) Old Feb 25th, 20, 4:09 AM
 
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Re: Stamped rockers BBC

OEM big block rockers will have a letter identifier......








H Rockers were used on later high performance engines 1970 and up. #3959182
L Rockers were used on early high performance engines 1969 and down. #3860308
X Rockers were used on 1965-66 high performance engines.


These are long slot rockers designed to work with OEM high lift cams of those years.


Hope this helps,


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post #15 of 43 (permalink) Old Feb 25th, 20, 6:04 AM
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Re: Stamped rockers BBC

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Originally Posted by mrpaticular View Post
.....But sometimes at the track the announcer will ask if anyone has an available roller. I'll stick with solid flat tappets.
Yeah, some racers at the drag strip will be running big solid roller cams with incredible pressures from triple valve springs in the 700-900 LB range. So that's gonna be tough on parts over the long haul.

Sometimes I wonder if certain parts become "the sacrificial lamb" in a certain sense. Example: if you're running a huge solid roller cam with a ton of valve lift, ( ie. .800+") you need to use real heavy/stiff valve springs as well as tough thick-wall pushrods which won't flex, and that can place lots of pressure and stress on the rocker arms. But if you lighten up on the valve springs and use more pliable/flexible pushrods that will give a little bit to soften the blow placed on the rocker arms, then you'll end up destroying the camshaft lobes and/or the valves and their seats due to valve bounce, and valve float. So perhaps the rocker arms have to take the hit and become the sacrifice in order to preserve other more expensive and more labor intensive type parts.

If you're drag racing your car, what would you rather have fail? A few rocker arms, or a camshaft and/or a valve along with it's seat? Of course some roller rocker arms can be more expensive than camshafts, a valve, and valve seat, sure. But it's a whole lot easier to replace rocker arms than a valve seat, or even a camshaft. In a perfect world ALL the valve train parts wolud be up to snuff and long-lived. But drag racing is never a perfect world. Almost always there are trade-offs. But I digress.

Going back to the comments about roller rocker arms on street cars, I'd much rather have rollers than stamped steel. Lotsa increased friction with stamped steel rockers. If you're running in a rules-limited race class which doesn't permit rollers,that's different. Or if you have a street car with a camshaft exhibiting less than .500" lift at the valve or less than 400HP at the flywheel, then it isn't like you need roller rocker arms. But if you're playing with a 500+HP build, and .550"+ lifts at the valve, I think it's a no-brainer to use roller rocker arms. After all, back in the 60's and 70's when our beloved Chevelles, (and Camaros and Novas) were coming off the assembly line, very few cars came with 500+ hp and/or valve lift more than .550" from the factory, and even the rare ones that did were mostly the special order cars requiring some type of special order code which the car salesman didn't even know about, (deleted radios, no heaters and the like). So factory cars got by with stamped steel rocker arms back then. JMO.
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