Cam Setup For L31 350 Vortec

[rebelyell]

I dont mind at all ive learned more reading this whole thread back thru then ive learned posting my question, one last question though im going to thru with full rollers and i found a a pair of self aligning rockers that are also full rollers and was seeing what you thought of them or if should go with guide plates and normal full rollers. (Im matching the heads to accept screw in studs). I also am doing the alex parts springs and verifed that it will fit on my heads.

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I don't KNOW if those RAs are narrow-enough to fit in rocker valley of iron Vortec L31 heads (I understand those are heads you're using) while ALSO affording enough room in-between RAs for the Vortec Valve Cover CenterBolts to fit without interfering with RAs. Suggest ask summit if they are narrow-enough for Your heads. At same time, perhaps ask summit who manufactures those RAs? Perhaps they're made by Scorpion; perhaps not. Scorpion is a very good quality USA-made aluminum RA. Summit claims their $375 RAs are USA. I would not install a die-cast aluminum RA.
As you've observed already; never install a self-align RA with a guideplate. Only one or the other.
I also prefer steel RAs over aluminum. But I also avoid chinesium valvetrain; regardless of material. However, I'm familiar enough w/ Alex's parts to KNOW that none of their Vortec kits' spring pressures are so high that it should REQUIRE a steel full-roller rocker arm such as Crower. Frankly, I'll suggest a set of Stamped Steel, pivot ball, self-align RAs from Elgin's Black Ice line (Black Ice are cryogenic-treated). BTW, Elgin's sets include eight RAs; requiring Two sets per motor. But, if I were so inclined to go full roller with relatively mild valvetrain, I might also install threaded RA studs, guideplates and "Normal" Non self-align RAs. It seems you're intent on having screw-in studs; so, do the guideplates as well but without self-align rockers. But, I'm not so inclined to run full rollers here. As for guideplates, suggest split/adjustable guideplates; instead of one-piece.

Ya do know the following, right? --- stud industry standard for Bottom thread is Coarse 7/16-14 --- while some have Fine 7/16" Top and others Fine 3/8" Top. It's true the larger 7/16" Top is sturdier than 3/8" --- but ya must choose RAs according to whatever size-diameter Top of stud is.

Cheap or pricey, small or large, No Stud can withstand coil bind etc; verify all clearances.

If/when ya change RAs from OE to aftermarket, plan on needing different Length PushRods too.

Suggest have any old heads tested for cracks/warping BEFORE ya commit to Any other parts & labor.

 

[TStowell]

I don't KNOW if those RAs are narrow-enough to fit in rocker valley of iron Vortec L31 heads (I understand those are heads you're using) while ALSO affording enough room in-between RAs for the Vortec Valve Cover CenterBolts to fit without interfering with RAs. Suggest ask summit if they are narrow-enough for Your heads. At same time, perhaps ask summit who manufactures those RAs? Perhaps they're made by Scorpion; perhaps not. Scorpion is a very good quality USA-made aluminum RA. Summit claims their $375 RAs are USA. I would not install a die-cast aluminum RA.
As you've observed already; never install a self-align RA with a guideplate. Only one or the other.
I also prefer steel RAs over aluminum. But I also avoid chinesium valvetrain; regardless of material. However, I'm familiar enough w/ Alex's parts to KNOW that none of their Vortec kits' spring pressures are so high that it should REQUIRE a steel full-roller rocker arm such as Crower. Frankly, I'll suggest a set of Stamped Steel, pivot ball, self-align RAs from Elgin's Black Ice line (Black Ice are cryogenic-treated). BTW, Elgin's sets include eight RAs; requiring Two sets per motor. But, if I were so inclined to go full roller with relatively mild valvetrain, I might also install threaded RA studs, guideplates and "Normal" Non self-align RAs. It seems you're intent on having screw-in studs; so, do the guideplates as well but without self-align rockers. But, I'm not so inclined to run full rollers here. As for guideplates, suggest split/adjustable guideplates; instead of one-piece.

Ya do know the following, right? --- stud industry standard for Bottom thread is Coarse 7/16-14 --- while some have Fine 7/16" Top and others Fine 3/8" Top. It's true the larger 7/16" Top is sturdier than 3/8" --- but ya must choose RAs according to whatever size-diameter Top of stud is.

Cheap or pricey, small or large, No Stud can withstand coil bind etc; verify all clearances.

If/when ya change RAs from OE to aftermarket, plan on needing different Length PushRods too.

Suggest have any old heads tested for cracks/warping BEFORE ya commit to Any other parts & labor.

Ive also thought about getting new aluminum heads that are ported and polished to help with flow and to shed some weight i also like those black ice rocker arms. Is there an advantage to going to screw in studs? all ive seen is it can be easier for finding more lifters since you could have whatever stud is needed.

 

[rebelyell]

The advantages of screw-in studs versus pressed-in:
screw-in can't pull out while running (although OE L31 vortec studs are more resistant to pull-out than are other heads)
screw-in far easier to R&R.

OTOH, if you run a milder cam (such as summit 8800), new ported & polished heads offer little performance advantage over OE L31 vortec.
Machinework to properly convert a press-in head to screw-in ain't exactly cheap either. And there's that risk of cracking stud boss while extracting a pressed-in stud.

On and on. It's all a balancing act; Cost versus Benefit.

 

[Suburbarn]

I do intend on trying the concept. A 4.3L Vortec is nothing more than a 350 Vortec with 2 cylinder chopped off. Also FWIW the last of the L31 350s put into the later model GMT800s (2003+) had the same setup in them, just impossible to find the OE rocker stands for the 350 here in the US. I opened a 2005 L31 350 up for valve cover gaskets and it had the same rocker setup as the later 4.3L. That later 350 had a lot of changes compared to the US built ones as well, like LS 4-bolt mounts and metric threads on the bellhousing and engine mounts. Those 350s were also EGR deleted, catless exhaust, used the 85mm LS MAF, and had the newer MPFI spider in them from GM. Those rockers give much of the same benifit as a Jesel shaft mount system in terms of valvetrain stability without the complexity of setting one up or the cost. Disadvantage is it is not adjustable, but I need pushrods anyway for the smaller base circle on the new cam.

Would these suffer the same failure mode as the LS rockers when used with higher spring rates?
I also noticed this style is used in a 2005 vintage 3800. I believe the whole assembly was supplied by Torrington.

 

[TStowell]

I don't KNOW if those RAs are narrow-enough to fit in rocker valley of iron Vortec L31 heads (I understand those are heads you're using) while ALSO affording enough room in-between RAs for the Vortec Valve Cover CenterBolts to fit without interfering with RAs. Suggest ask summit if they are narrow-enough for Your heads. At same time, perhaps ask summit who manufactures those RAs? Perhaps they're made by Scorpion; perhaps not. Scorpion is a very good quality USA-made aluminum RA. Summit claims their $375 RAs are USA. I would not install a die-cast aluminum RA.
As you've observed already; never install a self-align RA with a guideplate. Only one or the other.
I also prefer steel RAs over aluminum. But I also avoid chinesium valvetrain; regardless of material. However, I'm familiar enough w/ Alex's parts to KNOW that none of their Vortec kits' spring pressures are so high that it should REQUIRE a steel full-roller rocker arm such as Crower. Frankly, I'll suggest a set of Stamped Steel, pivot ball, self-align RAs from Elgin's Black Ice line (Black Ice are cryogenic-treated). BTW, Elgin's sets include eight RAs; requiring Two sets per motor. But, if I were so inclined to go full roller with relatively mild valvetrain, I might also install threaded RA studs, guideplates and "Normal" Non self-align RAs. It seems you're intent on having screw-in studs; so, do the guideplates as well but without self-align rockers. But, I'm not so inclined to run full rollers here. As for guideplates, suggest split/adjustable guideplates; instead of one-piece.

Ya do know the following, right? --- stud industry standard for Bottom thread is Coarse 7/16-14 --- while some have Fine 7/16" Top and others Fine 3/8" Top. It's true the larger 7/16" Top is sturdier than 3/8" --- but ya must choose RAs according to whatever size-diameter Top of stud is.

Cheap or pricey, small or large, No Stud can withstand coil bind etc; verify all clearances.

If/when ya change RAs from OE to aftermarket, plan on needing different Length PushRods too.

Suggest have any old heads tested for cracks/warping BEFORE ya commit to Any other parts & labor.

After looking at prices and everything i decided i will check my heads and make sure they are in good conditon W/ no cracks and use the stock studs. If the heads are cracked or not in good condtion i will go with the aftermarket aluminum heads as i want to build this motor over time and this way i would not have to buy new heads twice. I also wanted to verify that these were the rockers you were talking about. They seem very nice and with the rocker ratio staying and 1.5 coil binding wont be a problem.

Elgin, Long Slot Steel Rockers, Chev SB (87-Up), 3/8", 1.50 Ratio, Self Aligning - Competition Products

Elgin, Long Slot Steel Rockers, Chev SB (87-Up), 3/8 1.5BR Chev SB (87-Up), 3/8 1.5, Self AligningBR Stamped from high strength steel alloy, specially heat treated and designed to resist rocker arm flex. Long slot design to handle high lift profile cams. Each kit includes special grooved rocker...

www.competitionproducts.com

 

[L31MaxExpress]

Would these suffer the same failure mode as the LS rockers when used with higher spring rates?
I also noticed this style is used in a 2005 vintage 3800. I believe the whole assembly was supplied by Torrington.

LS rockers are lift limited by design. The end caps GM used to retain the trunion bearings have limiter slots in them. Probably done to ease install in the production environment.

 

[rebelyell]

After looking at prices and everything i decided i will check my heads and make sure they are in good conditon W/ no cracks and use the stock studs. If the heads are cracked or not in good condtion i will go with the aftermarket aluminum heads as i want to build this motor over time and this way i would not have to buy new heads twice. I also wanted to verify that these were the rockers you were talking about. They seem very nice and with the rocker ratio staying and 1.5 coil binding wont be a problem.

Elgin, Long Slot Steel Rockers, Chev SB (87-Up), 3/8", 1.50 Ratio, Self Aligning - Competition Products

Elgin, Long Slot Steel Rockers, Chev SB (87-Up), 3/8 1.5BR Chev SB (87-Up), 3/8 1.5, Self AligningBR Stamped from high strength steel alloy, specially heat treated and designed to resist rocker arm flex. Long slot design to handle high lift profile cams. Each kit includes special grooved rocker...

www.competitionproducts.com

No. But Close. Instead, use following:

Elgin PN = ICE410737
is a set of EIGHT 1.5:1 RAR, long slot, 3/8" stud Self align. These are Cryogenic treated. (the ones you show ELG6728 are Not cryo).
order two sets for entire motor. At minimum for assembly prep: DO smear pivot balls+adjoining stamped seats w/ moly paste or CMD #3. Same for PR tips-ends, same for Valve tips.

https://www.elginind.com/wp-content/uploads/2018/12/Elgin-2018-ProStock-Catalog.pdf

If, IF you can find a set of "Kool Nuts" which replace standard rocker nuts; they are OE on x602 CT crate motors. Those were made by crane but I dunno who supplies em now. They do exactly as they're named. They help cool the oil as it run over the rocker nut and down onto pivot balls. Heat is primary killer of highly stressed stamped pivot ball rockers.