Best valve springs?

[Rocket Man]

I have Vinci dual springs on both mine, along with their cams, hardened pushrods, Vitron seals, and if you really want peace of mind get some Yella Terra shaft-mount full roller rockers like I have on my 02. They’re badass. Roger Vinci sells them too, he co-engineered them.

 

[swathdiver]

...dual springs have no downside that I know of besides a slightly higher initial cost.

They don't like to rev as high or as quick, that's why the LSs use the beehives. ALL of my prior GM cars, even ones that rarely saw 5000 rpms had dual valve springs.

 

[Geotrash]

Since you'll have the heads off, may I suggest a shave to get the chambers down to 65 or even 64 CC and some thinner head gaskets to net .035" quench?

Yes, I'm open to that - thanks for suggesting it. Has it added to your engine's performance appreciably?

 

[Geotrash]

I have Vinci dual springs on both mine, along with their cams, hardened pushrods, Vitron seals, and if you really want peace of mind get some Yella Terra shaft-mount full roller rockers like I have on my 02. They’re badass. Roger Vinci sells them too, he co-engineered them.

Thanks for the pics. I like the Whipple

Saw the Yella Terra stuff on his site. Pricey. Now you have me thinking about power adders

 

[iamdub]

Yes, I'm open to that - thanks for suggesting it. Has it added to your engine's performance appreciably?

Since I put in a performance cam and looser converter when I did all that, I can't tell (feel) what the shave and thinner gaskets did exclusively. But, there's no way that they didn't make any positive change. Raising the compression boosts power and torque across the entire rev range. It's also "free" mod since the heads should be getting a cleaning pass when they're off. If the machinist has them set up for the cleaning pass already, it only takes a minute to shave off a little more.

Disregard the numbers I rattled off earlier, that was my 5.3 brain speaking. Your 6.2s are advertised and having 10.5:1 CR and 70cc combustion chamber volume. Raising the compression to around 11 would be nice. 91 octane or higher would be mandatory, although you should be running that already. If you get a mild performance cam, the raised compression would counter the possible slight loss of low-end power it may cause. It'd be a gain regardless.

At least with the 5.3 and probably most any LS, the chamber volume is usually larger than advertised, by 1-2cc. So, even if milling the heads is done just to get the chamber down to spec, it'll be an improvement. I don't know what the stock quench height is on these engines, but .036" is widely known as ideal. Tighter quench promotes more efficient fuel burning. Like the raised compression, this mod wouldn't cost much either. You'll already be needing head gaskets, which are around $60 for the pair. Cometics are about $60 EACH, but that's still only an extra $60 added to the project.

 

[Geotrash]

Since I put in a performance cam and looser converter when I did all that, I can't tell (feel) what the shave and thinner gaskets did exclusively. But, there's no way that they didn't make any positive change. Raising the compression boosts power and torque across the entire rev range. It's also "free" mod since the heads should be getting a cleaning pass when they're off. If the machinist has them set up for the cleaning pass already, it only takes a minute to shave off a little more.

Disregard the numbers I rattled off earlier, that was my 5.3 brain speaking. Your 6.2s are advertised and having 10.5:1 CR and 70cc combustion chamber volume. Raising the compression to around 11 would be nice. 91 octane or higher would be mandatory, although you should be running that already. If you get a mild performance cam, the raised compression would counter the possible slight loss of low-end power it may cause. It'd be a gain regardless.

At least with the 5.3 and probably most any LS, the chamber volume is usually larger than advertised, by 1-2cc. So, even if milling the heads is done just to get the chamber down to spec, it'll be an improvement. I don't know what the stock quench height is on these engines, but .036" is widely known as ideal. Tighter quench promotes more efficient fuel burning. Like the raised compression, this mod wouldn't cost much either. You'll already be needing head gaskets, which are around $60 for the pair. Cometics are about $60 EACH, but that's still only an extra $60 added to the project.

Thanks for this helpful detail, Chris. I think this is a mod I would like to make. I always run premium fuel anyway and as you say, I'll have the heads at the machine shop for cleaning and finishing anyway.

Since I'm new to the Richmond area, I'm still figuring out where the good performance and machine shops are. But we're about 5 minutes from the Virginia International Raceway, so the performance car culture here is alive and well. Found a good performance shop on Tuesday for the tune and got a good lead on a machine shop from a neighbor yesterday. My next call this morning will be to Vinci. And so it begins...

 

[iamdub]

Thanks for this helpful detail, Chris. I think this is a mod I would like to make. I always run premium fuel anyway and as you say, I'll have the heads at the machine shop for cleaning and finishing anyway.

Since I'm new to the Richmond area, I'm still figuring out where the good performance and machine shops are. But we're about 5 minutes from the Virginia International Raceway, so the performance car culture here is alive and well. Found a good performance shop on Tuesday for the tune and got a good lead on a machine shop from a neighbor yesterday. My next call this morning will be to Vinci. And so it begins...

You're gearing up for some good stuff!

For the machining, my suggestion is to ask the speed shops who handles their stuff. You should get plenty of references. The LS, using MLS gaskets, requires a very smooth finish (called "RA" for "Roughness Average") of around 30 or lower. Most any machine shop would know this, but there are some that would leave a finish that'd rival that from a wood rasp. IMO, a ~$100 shave and extra $60 for the gaskets is a huge bang-for-the-buck upgrade that you'll feel. The extra torque from the raised compression and better efficiency from the tighter quench coupled with a cam that starts to come alive around 1500-2000 RPM will help your cruising power. This will lead to less required throttle input which means better cruising/highway MPG. I gained about 3MPG at 70 with mine. Yeah, I now get BETTER MPG than I did with AFM.

 

[Geotrash]

You're gearing up for some good stuff!

For the machining, my suggestion is to ask the speed shops who handles their stuff. You should get plenty of references. The LS, using MLS gaskets, requires a very smooth finish (called "RA" for "Roughness Average") of around 30 or lower. Most any machine shop would know this, but there are some that would leave a finish that'd rival that from a wood rasp. IMO, a ~$100 shave and extra $60 for the gaskets is a huge bang-for-the-buck upgrade that you'll feel. The extra torque from the raised compression and better efficiency from the tighter quench coupled with a cam that starts to come alive around 1500-2000 RPM will help your cruising power. This will lead to less required throttle input which means better cruising/highway MPG. I gained about 3MPG at 70 with mine. Yeah, I now get BETTER MPG than I did with AFM.

Very helpful guidance once again, Chris. Thank you. I'm corresponding with Roger as I write and will order the cam, lifters, trays, springs, etc. as soon as he's able to work up the quote. I sent him all of my details about the way I use the truck and prefs, and he recommended the M/T 578/587/213/222/115+3A cam. I'll lose the VVT but that's okay for me. Such a pleasure to be able to work with someone who knows his stuff so well. Thanks again to everyone here for pointing me to Roger.

 

[Geotrash]

Talked to Roger on the phone today and ordered the parts. He’s generous with his time and generous of spirit. He gave great advice, suggested that shaving the heads down by 25 thousandths would be about perfect, and made a slight adjustment to the pushrod order accordingly. Nothing makes me happier than doing business with competent people I can admire and respect. Thanks for the joy this week, gents!

Dave


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[91RS]

PSI 1511.