JimMueller

iTrader: (9)

I realize it's a shot in the dark, but LGM setup one of them with stock milled heads, perhaps Louis will have ideas. If I can get there with a 416 and a mostly stock topend, that'd be all right. Maybe just get the shortblock and move what I can from my top end over, and a new cam. If I'm not happy with that, make it phase 2 and revisit the H/C/I.

I want to subjectively spend enough to make it reliable and meet my goals, but don't want to spend a premium where it isnt needed.

TrickFlowTech

If you already have a LS3, here's a nice little combination for the money: Al Noe's LS3 has a 4.070 bore / 4.125 stroke (427), standard TFS 255 LS3 heads, stock LS3 intake and tb, Trunnion kit rockers and 1 7/8 headers and full exhaust, mid 11's compression and a smallish 230@ .050 cam (TFS-32603001) to make 537/521. Conservative timing for hot track days, standard pullies full AC accessory drive etc....-no dyno tricks to hit that number. He beats the living heck out of it at track days and it's pretty docile as well at idle.

http://www.onallcylinders.com/2015/0...y-cruiser-too/

TrickFlowTech

I also noticed your comment on not doing the top and bottom at the same time. The same top end and cam could be run on a stock LS3 bottom end for now. Then just do a stroker short block later when the wallet recovers and pick up the remaining torque.

JimMueller

iTrader: (9)

Yes, I have an LS3 377ci already. Everything I've read hints that unless you have special pistons to compensate, or special cylinder liners, you shouldn't use a stroke >4.0" on a OEM LS3 block. As a result I had no interest in going over a 4" stroke unless I needed to, and even then it wouldn't be in a LS3 block.

NAVYBLUE210

Alot of good ideas (except stroke greater than 4.00" IMO)

Either AFR or TFS LS3 Heads and the stock ported Intake
Will work for your goals. The challenge boils down to the
Stock stroke/Displacement/compression ratio (street gas)
Relatively large Heads for your 1500-4000 RPM torque
Goals.

It would probably require a small cam,
Something like 220/226 VS 4.00" stroke with ~230/238
Cam, and would easily exceed your goals at both ends of the
2500-6500 Range with better manners as well.

TrickFlowTech

Yes, I'm just a big of fan with the 416 too....just reporting what was in Al's 427 as it has been running successfully. I did get a chance to take a look at the pistons when it was getting the new heads. It's a Mahle piston with normal skirt wear and no detectable piston slap.

HioSSilver

iTrader: (8)

A buddy and i made his bolt on ls3 get to 470whp/470wtq in a 1le 5gen. Be a great engine for running in the rpm range your looking for and would run forever.

Patron

Mr. Mueller 4 inch cranks horror stories are no longer playing at any local theaters. Stock cubes with head work and a LLSR or stroker with a factory top. Just keep it simple and get with a good cam guy. You'll be happy.

KCS

iTrader: (20)

Just to clear things up, pistons for a 4.125" stroke crank are no more "special" than pistons for a 4" crank. Wiseco offers a line of shelf stock pistons just like they do for 4" and 3.622" stroke combos.

I was hoping to have my stroker with unported LS3 heads running next month and have results, but Harvey has helped delay that a little longer. That's spilled milk compared to what other are going through so I can't complain.

JimMueller

iTrader: (9)

My current 377ci has 4032 alloy pistons sticking out of the hole roughly .010-.011", and they have 5cc valve reliefs. I'm not crazy about the valve relief's impact on compression, but I picked them for the alloy and weight (439g). Can heads have metal added to the chamber to effectively reduce the size of the valve relief? If yes, can it properly be done without having access to the heads/block?

I'd like to stay with the current bottom end, and add a new top end (and perhaps a different cam) to maximize the combo towards the aforementioned goal. If I still miss my goal, then I'd like to move over as much of the top-end as possible to a 416 short block. I'd rather stick with the square port heads rather than paying the FAST tax. So what would I be getting with a AFR/TFS/PRC aftermarket casting vs a Frankenstein OEM ported casting that benefits my goal?

If I can't reduce the size of the valve reliefs, then it would take a 61cc chamber and a .045/4.08 gasket to get me to 11.5 compression and .034 quench (or 11.35 compression & .040 quench with .051/4.08 gasket). Although the quench wouldn't be as tight, I'd rather use the GM gasket than Cometic for simplicity. Can I go that low on the chamber size without causing other fitment issues? Frankenstein said the flow is lowered 8CFM on their ported OEM castings when milled to 62cc; I think I'd rather have the compression than the extra CFM.

Assuming I would go with the 11.5 compression, my current cam 1/41/49/1 (which has an advertised IVC of 65.5) would give a DCR of 9.1, which seems high for 93 octane, but perhaps okay with the .034 quench. If I need to worry about changing the AIVC to lower DCR, then I'd need AIVC closer to 70.

KW Baraka

iTrader: (7)

With 11.5:1 compression ratio, go with the tightest quench practicable. In my book, that would be .040" or .045" gasket thickness. Seriously.....I wouldn't skimp on this!

Signed.....the guy running 12:1 CR on pump gas.

spanks13

iTrader: (5)

You'd be smacking the head at .034 quench.

JimMueller

iTrader: (9)

Still too tight even accounting for metal expansion as it heats up, eh?

NAVYBLUE210

Any updates?

JimMueller

iTrader: (9)

I rebuilt the 377 LS3 as a 418 LS3 in the summer of 2019 and installed a True Trac differential. I've been fighting a catch can issue in a recent thread, so I'm trying to ensure the supporting systems are up to the task before going further. Street tuned the idle & fueling with calibrated wideband but never optimized spark or got it on a dyno. Can't rev it past 4K right now without having hydraulic clutch problems. If interested in the engine specs, see my ModList in the signature.

Things I've completed since the engine rebuild:
* Installed LS9 valve covers with better baffling
* Swapped in LS9 coils & harness
* Upgraded from LS3 injectors to FIC 50lb/hr@4BAR injectors and new fuel rail
* Swapped from Pro 5.0 shifter to MGW
* New Rival S tires
* New street pads & high carbon C5 rotors
* Replaced leaking steering rack
* Installed larger FT lid, still not happy with the CFM limits of the factory size air filter, unsure what options there could be for large cone filters other than Volant or where they could be securely mounted where adequately large hose could be routed. Don't want to eliminate hood latch or wiper fluid reservoir, don't want to block any parts of the heat exchangers.
* Switched from the Braille 21 battery back to a full size battery due to concern with the Braille's ability to handle the additional compression and displacement.
* Swapped clutch from a LS7/Fidanza to a Mantic 9000+ Twin Ceremetallic
* Rear main seal service (old cover was not sealed correctly by engine build shop)

Next:
* Replace C6 caliper seals as one is ripped open.
* PCV: Looking at the MM PCV + fitting top conversion. Trying to locate a second can for the clean side that I can mount in the F-body engine bay with all factory accessories, assuming the MM can will mount on the right head.Right now I'm considering -10 hoses off the valve covers, going to a T, then to the 2nd can. Using inline sintered bronze filters as needed. The Saikou Michi design would be the easy button, but I don't think their design is as robust as MM for the dirty side.
* Fuel pump: Haven't had an accurate fuel gauge since 2010 when we installed the Racetronix kit. I want the new WS6Store complete drop in kit to hopefully fix it all.
* Heads - I'm mostly entertaining the Fed LS3 S1 heads, although what We Todd Did got out of the Liberty heads has intrigued me. I just don't know that I want to pay the premium for aftermarket castings. I'm a little concerned about the Fed 288cc intake port size, though, wish I knew the minimum CSA of the intake port. I still don't want to pay the FAST cathedral tax.
* Cam: Considering a stick that will carry a bit better up top without significant impact in the 3000 RPM range. Considering going from IVO 6 IVC 46 EVO 60 EVC 2 to IVO 4, IVC 46, EVO 55, EVC 6
* Exhaust: Currently have 1.75" ARH headers, want to upgrade to 1.875" headers. 2" headers lose too much torque in the lower RPMs. A race peer built a completely straight upper panhard brace, and I bought a copy from him. Haven't installed it. If I go with dual exhaust I should have what I need for clearance without the S-bends of the UMI/BMR/etc designs. I despise how the cutout sounds without cats.
* Gearing: I still have 3.73 gears, undecided on whether I want to go with 3.55's or 3.42's. Top end speed in the 1:1 gear vs a bit more mechanical gearing on the remainder of the road course. With a different cam I could eek out a few more RPMs but I'd be in this upper RPM range much less frequently than in the lower RPMs near upper 3000's, so I"m leaning towards 3.55's. These Motive Pros are a bit noisy, probably going back to OEM gears and try to use the competition pattern on the drive side

ColeGTO

iTrader: (3)

I'd keep the 3.73's in it. There are more corners than straights and I think your lap times would suffer with less gearing coming out of a turn if you have the traction.

The time spent pulling out of multiple corners is greater than the time spent at the end of a long straight or two.

If you really can't handle the RPM at the end of the straight, set the limiter where you want the MAX to be and keep your foot in it.