1.6 roller rockers with stock cam?

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Fast_Z71

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One of my friends installed a set of 1.6 roller rockers on his LT1 with the stock cam and valve train. I figured since the L31 and the LT1 are very similar engines, I’m curious as to if the same upgrade could apply to an L31? I know that the Vortec heads can’t take a ton of lift, but the stock cam is small compared to some of the aftermarket options. In the end, it may not make a ton of extra power like a cam swap would, but for a bolt, it might get a little extra with all the other bolt-ons I've done to the truck. Is it worth doing is my question.
 

Schurkey

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Is it worth doing is my question.
Probably not. The "friction reduction" from the roller rockers isn't that important until the valve spring stiffness increases a lot above "stock". The extra lift is nice, as is a couple of degrees of effective duration...but I bet you'd have trouble telling the difference on a dyno.

I installed 'em anyway. (Aftermarket aluminum heads, 7/16 rocker studs, L31 cam.)
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Erik the Awful

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These will get you the benefit of a 1.6:1 ratio versus the factory rockers that aren't quite 1.5:1 at higher rpm. If you're not running over 5000 rpm for extended periods of time, rollers aren't worth it. The factory cam is small enough that the 6.7% increase in lift still only puts you at .442" lift total.
 

Supercharged111

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You can, but you may have to drill out the pushrod holes. I had to for my Comp Pro Magnums on my 1500 in sig, but L31MaxExpress has had better luck on other motors.
 

BOOT

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Think they make 1.6 SA stamped rockers but I'd also do a LS beehive spring swap. Higher ratio increases the intensity or demand on the springs plus they are old but that's not just why I'd go to beehives. The beehives have a lighter retainer/top-mass and even tho vortec engines went to a lighter retainer than older SBC, it's still heavier than a beehive retainer. Will it feel like nitrous, nope but it'll spin up a bit faster, even David Vizard said beehives make more HP on the dyno.

And like mentioned you may have to increase the hole size, the vortecs I have are kinda small pushrod hole wise but I've never put 1.6 stamped rockers on a stock cam vortec engine, so they may not move it enough. I did for my L98 but those alum heads are a lot more open in the pushrod area like the LT1 heads are.

Or if you wanna try something else

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Frank Enstein

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Probably not. The "friction reduction" from the roller rockers isn't that important until the valve spring stiffness increases a lot above "stock". The extra lift is nice, as is a couple of degrees of effective duration...but I bet you'd have trouble telling the difference on a dyno.

I installed 'em anyway. (Aftermarket aluminum heads, 7/16 rocker studs, L31 cam.)
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That looks like a TrickFlow twisted wedge head. Good heads. I wish they hadn't killed them.
 

Schurkey

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Yup--first generation Twisted Wedge, not "Gen II". I have a pair on my 'Camino, a pair on the K1500, and another pair "new in the box" that will likely go onto the '77 Nova.

They first-generation TW take a "special" intake rocker arm even though they're advertised as using "stock" rockers. Since I had to buy special rockers for the intakes, I got the comparable set for the exhausts, too.

They're a great entry-level aluminum head. Some have had machining problems that caused rapid valve guide wear; but I haven't noticed that on mine. I think the revised geometry of the "special" rocker arms help.
 

L31MaxExpress

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1.6 full roller rocker will add 10-15 ft/lbs across the whole rpm range but I would suggest a slightly stiffer beehive spring like a Pac1218 if you do the upgrade. The vortec springs are marginal to start with and only lose pressure as they age.

I would pull the heads, install 0.016" rubber embossed steel shim head gaskets, behive springs and drill the pushrod holes to 1/2". Then put a cam in it, but that is me.
 

Supercharged111

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1.6 full roller rocker will add 10-15 ft/lbs across the whole rpm range but I would suggest a slightly stiffer beehive spring like a Pac1218 if you do the upgrade. The vortec springs are marginal to start with and only lose pressure as they age.

I would pull the heads, install 0.016" rubber embossed steel shim head gaskets, behive springs and drill the pushrod holes to 1/2". Then put a cam in it, but that is me.

Got a link to those head gaskets?
 

L31MaxExpress

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Got a link to those head gaskets?
Felpro changed the coating recently from black to clear but the last set was definately coated when I ran my finger across them. Looks like they are 0.015" compressed now too. Some people copper coat them, but if the deck surface and head face is clean, not badly pitted and straight, I bolt them down and go. Worth a slight bump in compression.

 
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