It looks like I may need to replace my LS7 lifters in my LS3 longblock, so I thought I'd start putting together a minor list of upgrades if the heads need to come off.

Below is what's in the longblock, built in summer 2010. The only reason it has been opened since then was to replace a Katech oil pump (stuck relief valve) a few months after it was built and to install a Rick Crawford modified intake manifold in late 2013.

GM LS3 short block
LS3 crank, end play .003"
K1 012AE25613 rods (660g) & ARP2000 bolts
Clevite HD main bearings, clearance .0022-.0025"
ACL coated rod bearings, clearance .0016-.002"
SRP 279593 4.07" flat-top pistons, 5cc valve reliefs, 4032 alloy, 439g, clearance .0025", rod wrist pin clearance .0008", piston wrist pin clearance .0007", deck clearance .0010-.0011" above deck
JE JG31F8-4070-0 piston ring set, end gap .0185-.019"
LS7 lifters & trays
GM L92 heads with mild cleanup and reportedly a .020" mill (no proof)
PAC 1518 valvesprings
EPS 222/230 .597/.600 112+2 PatG cam
GM 7.400" pushrods
LS3 rocker arms (unmodified)

The car is 99% a daily driver, but once pulled double duty as my autocross car. No telling when I might get a wild hair to go back to it or try out an HPDE at a road race track; it sees absolutely no drag strip action, but some random exhibitions of acceleration on the street. So basically I want a very low maintenance setup, low seat pressures, very wide area under the curve (from say 3000/3500 through 6000/6500'ish), exellent parking lot manners, etc. I would like to stick with the existing cam.

I haven't been convinced that the price of aftermarket heads with high velocity runners (PRC 255, Mast 256 or TFS 255) are worth the published gains for me, so if the heads need to come off I don't think I'd consider any changes besides a bit more milling and possibly replace the valvesprings. Oh, if there's a simple modification which will help oil drain out of the passenger head faster under high lateral G I'd be interested in hearing it; oil will pool on long lefthand sweepers running race tires and exceeding 1.3G. I've read on the Corvette forum that there is a consensus that a .040 restricted pushrod is safe for street use without excessive wear... but I don't want to trade one problem for another either.

So far here's my list:
New GM lifter trays & bolts
Morel 5315 lifters
New GM LS3 head gaskets
New GM head bolts
Mill the chambers
Trend Txxx1353 3/8" x .135 wall pushrods (xxx is length)
Brian Tooley rocker arm trunion kit
water pump gaskets
New valvesprings?

Right now I come up with SCR 10.76, DCR 8.5 and quench ~.042" to the top of the piston (piston out of the hole ~.011" + GM LS3 gasket compressed thickness ~.053"). If you have valve reliefs does that affect the quench calculation? Wondering what combination of parts I could switch to to get a bit better SCR without the DCR getting too high for 92 octane. Might there be an endurance beehive valvespring with lower seat pressure which would work better than a 1518?

 

Looks great.

If you are really going to mill your heads .020", then you need to remove practically and equal amount from the top of your intake runners on your head where it mates to the intake manifold.

If you dont, the sunken port will now have a lip that dips into the air path.

 

Further research shows that quench isn't affected by valve reliefs. I've read elsewhere than the max you can mill a stock LS3 head without manifold fitment issues is .060, and with using the .006"=1cc, one should be able to physically drop up to 10cc's from the chamber before worrying about fitment.

So if I used a GM LS3 head gasket:

62cc: 11.14 SCR, 8.8 DCR, .042 quench
61cc: 11.28 SCR, 8.9 DCR, .042 quench
60cc: 11.42 SCR, 9.0 DCR, .042 quench

Hmm, I wonder if it's worth in the long run to swap cams or retard the current cam to lower my DCR a bit with the additional compression. With a 60cc chamber, I'd need an advertised IVC of 70 or later to keep DCR around 8.7. Right now the advertised IVC is 65.5.

 

I think I'm going to opt for the Chris Frank LS3 Stage1 heads, and revisit everything from the lifters up. In general unless there's a significant benefit to using a more expensive part, I'd lean towards a less costly version.

Lifters: Years ago I had a lifter spin in the bore (I believe it was a Caddy lifter) when I was using LSK lobes spec'ed by PatG in a 347 LS1. I suspect but don't definitively know that it was related to the aggressive cam; I recall the clearance between the lifter body and the lobe being a little tight. I also want to do what I can to not have excessive oil pooling in the heads on long track sweepers and spinning a bearing without going with a dry sump. For lifters, I'm trying to weigh continuing to use the stock lifter trays vs drilled lifter trays vs link bars, and standard vs larger wheels. And if Chris already has the heads, that would be the time to bore out the lifter bores for slightly larger OD lifters if I wanted real expensive lifters. I've also read about link bars breaking and if I had to pick one type of breakage (trays vs bar) over the other, I don't know which is the lesser of two evils. I'm not against using a short or limited travel lifter but any regular adjustments need to be relatively simple and not too time consuming. For now I'm considering the Morel 5315 w/ drilled OEM trays.

Rocker arms: I think I'd prefer to stick with the stock pieces due to their light weight and strength. I had planned for a trunnion upgrade, but read of various failures in those upgrades also. I know certain types of aftermarket rockers have more weight over the nose and are prone to breaking. Because of not wanting to use aftermarket rockers I think that limits my lifter choice, correct?

Pushrods: Settled on Manton 3 or 5 series, length dependent on the remainder of the parts. Preferably straight 3/8" with .120 or .145 walls; both Chris Frank and Al @Manton didn't think there would be a problem with reducing the orifice to ~.060" to help reduce oil pooling in the heads. Not sure if I should have a specific tip on either/both ends of the pushrod. Not sure how that affects viscosity selection?

Valve springs: I like the features of a beehive (less weight, better harmonics, etc) over a double, and am contemplating using the Comp Cams conical instead of the beehive... but being on the bleeding edge no longer interests me. I'm going to keep valve lift <.620'ish for the sake of longevity. For a beehive I'd pick the PSI 1511ML, or the Comp 7228 conical.

Head gasket: GM LS3 .051" compressed, 4.08" bore

Heads: FRH LS3 S1, with holes bored in the rear of the heads & AN hardware for a future external oil drainback solution.

Cam: Something which has excellent parking lot manners and easy to tune but matched to the heads and gives an excellent torque boost between 3000&6000RPM. Don't plan to spin it higher than 6200RPM on an open track until I'm statisfied that the oil pooling issue is addressed.

I'm now a little irritated that I bought the less expensive SRP pistons with 5cc reliefs because it's hurting my compression. But getting the Diamond 2cc versions would have delayed getting the daily driver back on the road. Chris Frank said the smallest chamber would be 62.5cc, which would put my SCR around 11.15 and DCR around 8.81 without a cam change.

While it's down I'll probably put in a crank scraper. I've been sitting on a new GM oilpan for years, which uses the updated oil filter size, not sure if that will go in immediately or later with the drainback solution.

 

I don't have a lot of advice to offer, but I am looking at a similar set of decisions. I dropped a valve due to a failed valvespring recently, and it ended up costing me a full rebuild. While I don't think this was specifically the cause for the drop, I was running beehive springs. The engine had set for a few years without turning, so I think the problem was the constant compression of the springs...

I've decided on the following list of parts:

FRH ported TFS GenX 255 castings
BTR .660" Platinum springs
2.165 / 1.60 valves (custom pieces for FRH)
66cc chambers
Stock LS3 rockers with Harland Sharp trunions
Morel 5315 lifters
Drilled lifter trays/guides
Manton 3-series 3/8" pushrods (they should fit, will confirm)
EPS-speced cam
Cometic MLS 0.051" head gaskets

Prior to the rebuild, I had a few occasions in which I lost oil pressure, according to my in-dash gauge (which is always going to be slow to respond). To help protect against this as much as I can going forward, I'm changing my oil pump (to a Melling 10295) and adding a 3-quart Accusump. I would have liked to step up to a dry sump, but with my combination, that would have been a $6k or so upgrade to get the system I want (my front drive setup would have had to be changed in addition to the dry sump setup).

Good luck with your setup.

 

Gimme a week and I should be able to post up results of a very similar build to yours and an almost exact comparison.

OLD: Full details here: https://ls1tech.com/forums/generatio...l92-build.html

That engine blew up (stock rod bolt let go).

NEW: forged LS3 shortblock, 3.5cc valve reliefs in flat top forged pistons, FRH Stage 1 LS3 heads, same everything else as before. This time I'll only have 11.0 compression versus 11.2 (FRH does more extensive porting in the chamber). And now I have a stage 1 intake and its 266cc vs. 255cc stock. I dont think I needed the extra porting. I went with a Cometic head gasket 2.085x.040 compressed height this time just to shrink some of the extra chamber volume of the new heads. So I gain maybe 5 cubes and lose .2 compression, otherwise identical. Goes on the dyno this week. Hold off on your purchase and I'll post up results.

The cheapest route is to deck the heads (max I've heard is safe is .045 not .065). I would do that and be done.

 

How many measurements do you have on the S1 head? runner volumes, CSA, flow numbers, etc? Is that stage 1 intake plastic or metal? My pistons are about .011 above the deck so I can't use much less than a .050 gasket.

Looking forward to your results, although with you having a Vette with a different driveline and especially the SuperPro headers I don't know how I could adjust your results to a F-body with ARH headers platform.

 

I never got a flow sheet on the first head: only chamber volume. The intake for both setups is a stock LS3 intake and throttle body. Pistons were .000 in the first setup and .006 out of the hole in the new setup.

Results are results since it's all the same before and after: if I gain from the FRH stage 1's then you could too. You don't necessarily need to be concerned about the exact correlation to a F Body. Make sense? I'm even having the same shop/tuner/dyno do the second engine so no change there either other than different days.

 

I've updated my desired parts list, and it's a little more expensive than I had forecast. Anything extremely overkill here where I could save some coin without hurting performance or reliability too much? Seems like a lot of $$$ for the projected gains. All the GM items are free shipping & no tax.

Johnson 2116SLR lifters $580
GM 12610046 head gaskets 2@$29
Manton Series 5 3/8" pushrods, .145 wall, .062" hole 16@$21
GM 12620951 LS3 assembled head, 2@$390
Comp Cam 7228TS conical spring kit (springs, locks, seats, seals, Ti retainers), $428
GM 17800568 head bolt kit, $23
GM 12630223 water pump gaskets, 2@$4
GM 12637683 valve cover gaskets, 2@$14
NGK TR55 spark plugs, $24
Firecore50 Ignition wires, $125
DEI 10542 ignition wire heat shields, $69
GM 12585673 front seal, $16
GM 12633904 timing cover gasket, $17
GM 12557840 crank bolt, $4
Matched cam, endurance lobe, <.620" valve lift, estimate $450

My valve cover gaskets were fairly unpliable when I took them off two weekends ago so that's why they are included. The existing spark plugs are almost 5 years old and the existing GMPP wires are probably about 15 years old.

I think the first item to be reduced would be the lifters, but I can't make up my mind on the trays... don't want them to turn, and I've read of instances of them being more likely to crack/turn when you drill them to help oil drain back. I know the setup on the SLR's is tedious, but I'm detail oriented and I don't think that will bother me, although I'd have to weigh it against the hourly shop time.

The above list alone is a little over $2900. Another $100-$200 in replacement fluids (SRF brake/clutch fluid, oil, etc.) The labor to machine & assemble the heads at Frankenstein would be another ~$1300-1400. I'm likely doing this on a shop lift, so maybe 2-3 hours shop time to R&R the engine cradle, plus shop time to R&R parts.

I'm coming up with approximately $4500 plus shop labor, which seems ridiculous for what I think I'll gain on this. I'm not sure what old parts I could sell as used which would be desirable other than the bare heads or what the going rate would be.

 

There are desired and required parts. Don't mix the two. All the required parts need to be zero'd out: you can not avoid the cost of those unless you want to park the car until you can stomach the cost of them. The only costs you should be comparing are desired vs. required; that is how I look at it at least.

 

I'll start a separate thread after this weekend as I'm prepping to go race. Short version: car made 522rwhp/480tq (SAE 5) on a glory pull, settled in at 515/480 but at 24 degrees timing. Old setup was 505/480 at 27 degrees. Above 5150rpm, the FRH Stage 1's picked up ~ 20hp/20tq over the previous combo ( exhaust/chamber/bowl ported LS3 heads).

So peak to peak (and we all know there is more to the story) +10hp + 0 torque (maybe up to +17rwhp more after it breaks in).

 

Did you get a copy of your dyno graphs by chance? I'll be more patient until after the weekend if needed, but figured I would at least ask. I'm curious to see them overlaid.

I'm curious at the timing difference also. Any explanation for that?

Good luck this weekend...

 

Haha, is that a GM sanctioned engine break-in schedule? Could you obtain & post the flow tables and port volumes for your FRH heads? What other type of activity does your C6 see other than road racing... how much daily use, etc? What pushrod diameter did you use? Did Chris make certain adjustments for you in the heads to accommodate your specific use?

I'm also looking forward to a dyno overlay!