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Old 02-22-2018, 03:39 PM   #26
Richard2112
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Re: Vortec head problem?

Wow Matt that's a great video. Who woulda guessed the stamped steel does so well. My question would be valve tip wear and spring pressure. Think the stamped steel, higher spring pressure and rpm would do well with a basically stock valve?
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Old 02-22-2018, 04:27 PM   #27
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Wow. Yea that video makes me want to find a set of 8 of the stock rockers and just replace the worst worn ones I have. Problem is I canít find that
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Old 02-22-2018, 04:39 PM   #28
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Re: Vortec head problem?

Maybe these?
https://sdparts.com/i-19870002-chevr...ms-qty-16.html

Not sure that's the best price, but from the description it comes from GM and is self-aligning.

EDIT: I see the issue now. For 16 of them it's $92. But for just one, it's about $26. Strange marketing. Find a buddy who needs a few and split the box. Summit has them, too. You'd think they'd be smart enough to split up a box of 16.
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(Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1

http://67-72chevytrucks.com/vboard/s...d.php?t=567340

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Old 02-22-2018, 09:50 PM   #29
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[QUOTE=mattfranklin;8194985]Maybe these?
https://sdparts.com/i-19870002-chevr...ms-qty-16.html

Not sure that's the best price, but from the description it comes from GM and is self-aligning.

EDIT: I see the issue now. For 16 of them it's $92. But for just one, it's about $26. Strange marketing. Find a buddy who needs a few and split the box. Summit has them, too. You'd think they'd be smart enough to split up a box of 16.[/QUOTE

I found some Sealed Power R973. Think those are a sufficient stock replacement?
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Old 02-22-2018, 11:36 PM   #30
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Re: Vortec head problem?

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I found some Sealed Power R973. Think those are a sufficient stock replacement?
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Really good question now-a-days. Sealed power used to be the go-to brand for many of us. I was talking to an old-school machinist a week ago and he said he used to prefer them for valves, but now he likes SBI valves because they were still made in the US. He's still very active in building racing engines, and is in demand so he knows what he's talking about. And he seems to know what's needed for stock vs light street performance vs racing. Next time I talk to him I'll have to ask him about rockers.

Not to sidetrack your thread, but I'll also be asking him about what I should do on mine. I'm following more of a Z-28 restoration path with mine (period correct 1970 LT-1 in my 1970 C10) . Surprisingly, on eBay I have seen *used* Z-28 / LT-1 stamped stock rockers are going for $300 per set.
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(Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1

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Old 02-23-2018, 01:17 AM   #31
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Since I believe Iíll run stock rockers. I attached a couple more pics of the ones I have. Yíall agree these need replaced? Also, whatís the lift limit with the stock rockers? Not sure if Iíd need long slots for the .480 lift.
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Old 02-23-2018, 02:08 AM   #32
mattfranklin
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Re: Vortec head problem?

In Summit's Q&A they say it will handle up to 0.550 lift, depending on geometry:
https://www.summitracing.com/parts/nal-12495490

BTW, you asked if they all look like they needed replacing. I think I've read that the recommendation for these is to keep the ball and rocker as a matched set. Now that they are separate it's probably good to replace all of them.
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Old 02-23-2018, 03:57 PM   #33
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Found the link for the Engine Masters roller rocker episode: https://www.youtube.com/watch?v=TvQHgt-tF7Y
Iím still iffy about the stock replacement rockers. In that video they are not using Ďstockí stamped. They are Howardís. Probably a true 1.5 ratio. Heck if you use a stock rocker thatís true 1.46 ratio that bumps my valve lift from .480 down to .467. Thatís under the next smallest cam in the XE lineup. Comp cam site claims their roller tip 1.52s make 15-30 hp. That has to be due to an accurate 1.52 ratio vs stock. Iíd like to have true 1.5-1.52 to know Iím getting the most from my cam.
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Old 02-24-2018, 02:17 PM   #34
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Re: Vortec head problem?

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Originally Posted by '69 Gmc View Post
Iím still iffy about the stock replacement rockers. In that video they are not using Ďstockí stamped. They are Howardís. Probably a true 1.5 ratio. Heck if you use a stock rocker thatís true 1.46 ratio that bumps my valve lift from .480 down to .467. Thatís under the next smallest cam in the XE lineup. Comp cam site claims their roller tip 1.52s make 15-30 hp. That has to be due to an accurate 1.52 ratio vs stock. Iíd like to have true 1.5-1.52 to know Iím getting the most from my cam.
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X2. Exactly
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Old 02-26-2018, 12:15 PM   #35
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Re: Vortec head problem?

Quote:
Originally Posted by '69 Gmc View Post
Iím still iffy about the stock replacement rockers. In that video they are not using Ďstockí stamped. They are Howardís. Probably a true 1.5 ratio. Heck if you use a stock rocker thatís true 1.46 ratio that bumps my valve lift from .480 down to .467. Thatís under the next smallest cam in the XE lineup. Comp cam site claims their roller tip 1.52s make 15-30 hp. That has to be due to an accurate 1.52 ratio vs stock. Iíd like to have true 1.5-1.52 to know Iím getting the most from my cam.
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That's a fair point. And if you went with the Howard's, you may need guide plates and screw-in rocker studs, and the machining that goes along with that. I don't think Howard's makes the self-aligning ones that the Vortec uses.
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Old 02-27-2018, 12:21 AM   #36
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Re: Vortec head problem?

Scorpion makes a good quality roller rocker in self aligning and for a bit less $$ than the competition.
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Old 02-27-2018, 06:23 PM   #37
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Re: Vortec head problem?

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Scorpion makes a good quality roller rocker in self aligning and for a bit less $$ than the competition.
Good call. That's one of the lower cost roller rocker brands mentioned in that Engine Masters rocker video.
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