So, the local shop that upgraded my stock LS3 (installed ~2009) to a 418 in 2019 used some brass shims under the rockers instead of being patient with measuring pushrod length for axle oiling lifters. Long story short, some of those brass shims ended up in the oil pan last year. Car would no longer maintain idle, and I parked it for months. I want to continue down that rabbit hole now. Short block bore is already maxxed out around 4.079", and it had an unusual amount of oil loss it's entire engine life. I'd rather not re-use this block. I dropped it off at a local shop to perform other work (refresh rear-end and axles, ship steering column away for rebuild, redesign fuel lines, etc).

1) I want the lighter aluminum block because it's setup for street/autox/HPDE, never drag.
2) I'd be okay with a 38x LS1/LS6 if such reliable short blocks can still be sourced. I like the LS1 because I don't want to change PCMs, so that means knock sensor works best in valley cover. Bu I also read an opinion that a 383/388 LS1/LS6 is not good for HPDE.
3) If I can get over nervousness (again) about KS not working to the best of its capabilities (even with minimal desensitizing), I could go to a Gen4 again, or does anything beyond Gen4 integrate fairly easily with the Fbody?

Ideally, I want Tony Mamo to build it, but I haven't called him yet. I've heard some poor customer service from Thompson; TSP & BTR got bought out? Katech might be viable, whom else should I consider?

The Monster triple clutch is working fine, albeit it has too much pause when the shifter moves through neutral even though I helped the tech measure everything during the clutch install. I bought the triple because I read that it might be a bit more civil than the twin. Now I'm wondering about a RPS CF Twin (perhaps Tony still customizes them).

Thanks.

 

A couple things to note here. An LS3 block can go out to 4.100, if the core shift isn’t unreasonable. I’ve seen them out that far with road race builds and not use oil. So there’s that. On the other hand, I have in the shop an NOS LS6 block that’s been in the crate since 02’, if you’re considering going back to a Gen3 build. Me and Tony work well together. I send him work and he sends me work. I just shipped him a LS3 block a couple weeks ago for a build for him. I source all my assemblies, camshafts, valvetrain, induction, and heads from Tony for my non-stock builds. His service is simply the best. Period.

 

I spoke with Tony about 20min tonight. He said he'd ask a friend if they had any spare blocks around and get back to me in a few days. I don't trust anyone local to validate my block can go out to 4.100.

 

For clarity, LS1/LS6/early LS2 blocks use a 24x reluctor wheel, later LS2s and Gen IV blocks use 58x wheels. IDK if you made a typo, or?? As for Tony, you'll find nobody better. The poor guy must get only 4 hours of sleep nightly, and put in 20 hour days. His customer service is the best. So is workmanship. You'll never be sorry. He's called me at home as late as 10:30 at night to discuss what he's doing, and to make sure we're on the same page with my goals!! He actually uses the telephone! Imagine that!!!I MUCH prefer phone conversations to emails. Regarding your motor, and its excessive oil consumption since it was rebuilt, maybe someone installed low tension oil rings? Who knows.....

 

So far I've only used reluctor wheels compatible with my PCM. I've not needed that Lingengelter module. Rings came with my Mahle pistons, I don't recall if they were low tension.

 

Reluctor wheels can be changed out, I have a gen 4 lc9 with a billet 24x reluctor wheel.

 

Just throwing this out there. Maybe have your current block the stock sleeves cut out and install ductile iron sleeves. Bore it to 4.125 with a 4" stroke for 427 cubes. I did that with a LS2 block. Steve at RED did all the block work. I used a Manley stroker kit. LS3 heads. Ran great and used zero oil.
Just thinking you could save your current block.

 

I don't need crazy power. I'm looking for a casual autox/hpde torque curve, decent lap times need good traction. I'd like something like 400-450rwtq by 3500, whatever the tires will hold by 6000-6500. Civil behavior under 2000.

 

The LS2 I had stroked to 427 cubes I used stock LS3 heads. LS3 intake. 225I/230E .610 lift. Upgraded valve springs and push rods. Built 4L60E trans with a 3200 stall from Yank. 373 gears.
On the chassis dyno it did 495 rwhp. Drove like a stocker until you floored it.
I put it in a 67 Nova.

 

Just emailed you Jim.....look it over and email or call me back

Cheers,
Tony

 

Availability aside, the main reason I'm considering the LS1/LS6 383 is the OEM PCM/knock sensor integration to help protect the engine during hot 20 minute sessions. While I've used LS1 sensors on the side of this LS3 block since ~2008, that doesn't help the electrical incompatibility. I generally put in Sunoco 100, then desensitize the tables very gradually to remove false knock. But I've never increased the sensitivity due to not locating any good methods. I really want the 416 but want to protect the investment also. How much can I trust the LS3 knock-sensor/PCM solution?

 

I thought my Helms manual would tell me, but I can't find it. The shop finally gave me a $ quote (wo hrs) to remove & replace engine assembly with AC. How many book hours should I be quoted for the complete engine swap, including charging AC and all the other misc tasks?

 

Long block RnR pays 22.9hrs. Thats a new motor with cylinder heads and transferring over everything off the old motor

 

Katech & Tony have received my deposits. Short block will be the link below except using the only spare LS3-type block they can spare... a new GM LSA block. They will plug the piston squirters. Compstar 24x crank & rods, Mahle piston kit. Pistons will be in the hole ~0.005". I don't have the exact list of parts included in Tony's top-end kit yet. I'm inferring his AFR 243X assembled heads w 10mm 1.8 rockers, LSXR intake, 102mm TB & camshaft. We're aiming for low 11'ish compression to help control heat during HPDE sessions. I'm more concerned about <5500RPM than >6500RPM.
Katech 416ci LS3 Short Block | NA

Below is a tentative list of additional parts. I'm trying to balance cleaning old parts that are safe to re-use vs buying new. If anything looks really odd, or compatibility concern, please call it out.

Qty 2 Permatex 82180 Ultra Black RTV
Qty Front/Rear Cover / Oil pan alignment kit?
Qty 1 GM 12639250 LS3 rear main cover with seal & gasket
Qty 1 Std Motor Products PS365 1998-unique LS1 oil pressure sender
Qty 1 Improved Racing EGM-501 Oil barbell
Qty 1 GM 12611129 Windage Tray
Qty 1 ACDelco 12612350 Oil pan gasket
Qty 0 Oil pan (re-use)
Qty 0 Improved Racing EGM-200 Pan baffle (re-use)
Qty 1 Improved Racing EGM-500 Oil pickup tube 2-bolt brace
Qty 1 Katech KAT-A2390 Oil pump
Qty 1 GM 12610141 Valley cover gasket
Qty 1 GM 12598832 Valley cover w/o PCV provision
Qty PCV system design unknown
Qty 1 GM 12589016 Camshaft retainer plate
Qty 1 ARP 134-1003 Cam bolts - kit of 3
Qty 1 GM 12588670 Timing chain dampener
Qty 1 GM 12586481 timing set - 3-bolt 4x cam gear
Qty 1 Katech KAT-7636 Timing set - C5R timing chain
Qty 1 GM 12556582 Timing set - crank sprocket
Qty 1 GM 12633906 Front Timing cover complete kit
Qty 0 ATI 917242 Harmonic balancer (re-use ATI or spare new)
Qty 0 ARP 234-2503 Crank bolt (re-use ARP or spare new)
Qty 0 ATI 918993 Pin the new crank (re-use? new kit if needed)
Qty 2 GM 12630223 water pump gasket
Qty 0 GM 252921 water pump option 1 (or ACDelco 252-921) (LS2 re-use)
Qty 1 ? Lifter kit - link bar
Qty 1 ? Pushrods
Qty 2 Cometic C5489-036 Head gasket (0.036"x 4.100"-ish)
Qty 0 ARP Head stud kit (re-use existing ARP)
Qty 1 FAST 146203-8 Intake manifold gasket kit
Qty 2 GM 12617944 Exhaust manifold gasket
Qty 1 NGK 4177 Spark plug kit, 0.040" gap
Qty 1 FAST 146032-KIT FAST Billet fuel rail kit
Qty 0 GM 19418807 GM LS1 MAP sensor
Qty 0 After Dark Speed FAST LSXR MAP sensor clamp bracket
Qty 1 FAST 146025-KIT FAST LSXR Injector Adapter kit (to re-use existing LS3 injectors)
Qty 1 ACDelco PF48E Oil filter break (0-30min runtime)
Qty 1 ACDelco PF48E Oil filter break-in (up to 100 miles)
Qty 1 ACDelco PF48E Oil filter break-in (up to 500 miles)
Qty 1 ACDelco PF48E Oil filter break-in (up to 1000 miles)
Qty 4 Driven BR30 Break in oil, 6 qt pack
Qty 1 Fram XG10575 Oil filter (after 1000mi)
Qty 6 Mobil 1 5W-30 Synthetic oil after break-in
Qty 1 Mamo/RPS BC2 Clutch
Qty 1 GM 24264182 OEM slave cylinder
Qty 1 GM 12557583 Pilot bearing

 

Just a brief update.

What I'm getting from Katech
LSA short block with 24x reluctor
piston squirters removed & sealed
Compstar 4" crank & rods
Clevite main & rod bearings, GM cam bearings
Mahle pistons, expected to be ~.005 below deck
Johnson 21216LSR tie bar lifters with custom OD to retain OEM lifter-to-bore clearance

The remainder of the big items are coming from Tony, and he's assembling the heads. Here are the big items off the top of my head.
Comp Cams 231/239 113+4 cam, about .64x valve lift due to 1.8 rockers
AFR LS1 245cc heads with his hand finished porting (aka Mamofied LS1 243x heads)
Manton Series 3 11/32" x .120 pushrods
Yella Terra Ultralite 1.8 roller rockers with 10mm bolts
Tony is picking the remainder of the valvetrain
Will need a taller valve cover gasket for arm clearance with OEM valve covers
FAST LSXR cathedral intake manifold, hand ported
New, taller injectors instead of using injector spacers. Fuel Injector Connection so I can get Greg Banish HPTuners data.
FAST fuel rails

water pump - keeping my fairly new LS2 model
oil pump - leaning towards standard volume & pressure. Will know more after I have been given clearances from katech. I can get Katech's OEM ported pump, or a hand ported Melling from Tony. Aiming for compression near 11.3 and DCR near 8.2.

That's the big stuff. Tony seems to be ahead of schedule, and Katech indicated last week my block was next in line to start. Maybe this thing will be drivable by July.

 

The block came back from CNC for rod clearance and is currently in the hone!