BTR spring kit is the best value for money. I've been running them in a cammed ls1 daily driver for years now and they still good. If you want to spend more money, PSI springs

 

Just a heads-up that I will be on a road trip for hiking in Missouri for 5 days during which I have very limited Internet access and therefore won't post here for those days.
I greatly appreciate all the feedback I have gotten so far; it prompted me to research and learn more. Besides the TFS replacement parts, I ordered the GM Performance "Racing" lifters from Brian Tooley.
Thanks again. Till next week...

 

@mrvedit since you already spent the money on the whole rocker arm setup, I wouldn't go backwards.

Regarding the 1208X's with a -0.050 offset, you are correct, that is to get the 180lbs seat pressure. We do offer ton's of lock options, with positive and negative offsets. Even with a -.050" offset, the 1208X has way more real estate than you would use up.

There are 1222X's out there, mostly at large distributors. If not, we always have them rolling through production.

Yes the PAC-1276X is an awesome spring. I am stock rockers but I ended up pulling duals out to replace with the beehives. I dropped my spring/retainer combo from 100g each to 70g each. 30% weight drop is significant IMO.

 

Just a thought. Any scoring on the valve stems? Maybe the valve was stuck in the guide.

 

Setting up the springs tighter to coil bind aids in the harmonics of the spring and control of the valve. Your shaft mount rockers probably didn't help in the control department. Being heavier over the valve tip, I mean. Spring probably just failed from fatigue. If there's not much damage, replace the full set, shim them to .060-.070" from coil bind and enjoy many more years thrashing your setup.

 

Even a tiny spot of rust on a valve spring can lead to a weak point. Some spring material doesn't like oils from human hands.

 

Back from a great trip of hiking with our 1-year old Dalmatian and Springer-Spaniel in Missouri, especially at the Johnson Shut-In and Castor River Shut-In.

The repair parts from TFS arrived - 2x valves and seats, completes set springs and seals. New GM Performance "Race" lifters and new gaskets from BTR also arrived. Already have the new BTR cam.
I plan to do a quick lapping of all valves, unless that is a bad idea.
For now will just use the TFS dual springs.

One thing I didn't mentioned here is that I was having AFR imbalance problems for a long time. My right bank was almost always leaner than my right bank, sometime by as much as 1.5 AFR. I posted this on the Holley forum and not even the experts there had any suggestions beyond what I had already done. While I could verify the Holley O2 sensors with separate wideband gauges with their own O2 sensors, swapped the Holley sensors. Swapped the injectors, tried new injectors. Ensured no leaks in the exhaust. Verified the injector and coil wiring; even resistance checks. Verified good compression and leak down tests on all cylinders. Even swapped intakes. Finally even bought a new Dominator ECU.
The imbalance tended to get worse with RPM and/or load, but not always.
I always concentrated on trying to figure out why the right bank was leaner, but in the near started to wonder if perhaps the left bank was richer.
I now wonder if perhaps the #1 cylinder intake springs were binding/breaking which was throwing off the AFR balance.
Something definitely was off a few days earlier as the engine temporarily lost power and made strange sounds, which I now recognize as the intake valve staying open. Yet the next day the engine ran fine and even revved to 7000 with perfect AFR balance. A half hour later the intake valve springs clearly broke as the engine again lost power and sounded even worse.

In short, I'm hoping this will also fix the AFR imbalance problem as I have barely driven the car in the past year due to this.

 

Since the weight of parts has been discussed, I made some measurements:

LS rockers with trunion upgrade = 160 Grams
Single Crower rocker = 162 Grams

BTR LS7 Lifter = 130 Grams
GM "Race" Lifter = 122 Grams

So overall I am loosing 2 Grams with the Crower rockers but gaining 8 Grams with the GM Race lifters. Yes, I know it's more than simple weight - the Crower rockers have more weight at the ends - a roller for the valve and an adjustment screw for the pushrod. So more "polar momentum".
However they are plenty of articles praising shaft rockers for better stability at high RPM. A major magazine test showed a 6HP dyno improvement of the Crower shaft rockers over LS trunnion rockers.

 

Now would also be a great time to maybe put in an LS3 intake valve which is waaaaay lighter than the TFS valves. I think the 9 year newer camshaft technology will really show you the potential for that motor.

On a customer 416 with stock LS3 heads/intake, 11:1 compression on 91 octane, BTR Stg 3 cam (maybe 4) with mid length headers and crappy 2.5" crush bent exhaust, T56 Magnum, 12 bolt running 335/30/18's in a C10 AutoX Road Race Optima setup it made 560rwhp. You have better heads so this time around I'm guessing you make more than this unless you put in a baby cam.

 

You cannot weigh the rocker as a whole, you need to weight the tip (valve side) from the fulcrum. I am sure you will see a huge difference in weight at that point.

Also, I do not care about pushrod or lifter weight. We use a general rule of thumb 80/20 for weights. The valve side weights make up 80% of the dynamics, whereas the lifter side only makes up for about 20% of the dynamics (taken from the rocker fulcrum) .

 

Never thought that anything other than TFS valves would fit a TFS head. I read that hallow LS3 valves are about 89 Grams; my TFS intake valves are 110 Grams.
Unfortunately from what I can find, LS3 valves are around 4.9" long while the TFS are 5.2" long, which would require different pushrods.
Thank you (!) for the good suggestion, but I'm in a hurry to finish this project as I have other auto projects waiting.

@Turbobuick - your 80/20 rule of thumb seems like a good way of looking at it; I would have guessed the ratio was only the 1.7 rocker ratio.

Again, thank you everyone. You have made this a great learning experience.

UPDATE: TFS sent me the wrong locator and I am therefore delayed by a few days. However none of the dual or beehive springs listed by anyone above are in stock anywhere and have a 2-week delivery time.

 

I don't think you will be able to get proper valve spring installed heights or retainer-to-seal clearance losing .300" from the valve's length.

 

Agreed. I looked at the competing AFR heads and they also use 5.2" long valves. Seems these aftermarket heads have a different valve angle for better flow and need longer valves.
A buddy wants to build a high revving (8500 RPM) 4.8L LS1 and I told him to look into the hollow stem LS3 valves for his build; he didn't know about them.

I have my new cam installed, lifters installed, all the valves lapped, heads cleaned and now ready for springs. Noticed that the exhaust valves need more lapping than the intake; the seats showed some pitting and tended to leak some water during the water leak test.
I will install test springs on #1 for camshaft timing verification. (I know, cams are made better now than in old days, but still a good exercise.)

 

Any updates, did you get your engine put back together. That BTR cam you chose is very good I here. Any dyno numbers? I'm putting together a LS417 stroker and just picking my cam specs.