Originally Posted by Tony Mamo @ AFR

It was a typical late night for me working in my shop at the house when my cell phone rang just after 10 PM yesterday evening. Turns out it was a phone call from my friend George Lara, a respected tuner in the So Cal area and an all around good guy. I had been waiting for this call for a few weeks, not to mention this project originated almost 6 months ago, but isn’t that par for these types of things anyway.

Back in April I had gotten involved with a C6 project belonging to Greg Schult….seems Greg and his brother Alex are somewhat competitive and with the two of them recently purchasing C6 Corvettes, the stage was set for some power mods to up the ante. Alex went the Magnuson forced induction route and put down some respectable numbers with basically the stock C6 short (490 RWHP / 490 RWTQ thru an A4) and Greg contacted me inquiring whether we could come close or possibly beat those figures with an N/A build. Initially we had moved forward with a package designed to optimize the stock 6 litre block in his car but somewhere between the start of this project and his brother on the dyno….LOL, Greg decided to get with LME on a 403 stroker to make things more interesting. Besides spec’ing a larger cam, most of the work on my end remained the same. We used a set of 205’s that I opened up the chambers and did some light porting work to optimize their small efficient ports (like I helped Pat G. and a few others with), ported a FAST and an LS2 TB, and sent him shopping with a list of the other supporting mods in the recipe (Yella Terra rockers, EWP, lightweight clutch, etc. etc.).

I was hoping to see around 525 RWHP with 500 TQ, and felt if everything really came together there was a chance it might make a little more. BTW, with a set of 1.875 Kooks headers already installed on the car (and a CAI as well I believe), on the same Dynopack wheel dyno over at Haddad Motorsports where the tune and the install was performed, the car put down 375/375 as a baseline prior to the engine swap. Pretty much solid textbook numbers for 364 CID engine and an M6 driveline with those mods (similar to others I have seen). The baseline dyno graph is included below to compare the data and shape of both curves….

Here are the final results….



I was especially surprised and pleased at how well the TQ curve carried without the band-aid of a monster sized cam which would have obliterated the bottom end and hurt drivability, essentially getting away from the well rounded package I was shooting for. While this technically isn’t an out of the box 205, the finished port volume is within a couple of cc’s of that showing once again that “area under the curve” flow coupled with good port velocity and a well thought out combination is more powerful than most realize. Picture the throttle response this animal has with all that power and a tiny 205cc intake port….its a lethal street combination.

This car made over 550 RWHP on five consecutive back to back runs (500-503 TQ) with the best registering 558 at an A/F ration George felt was a touch aggressive (13.7-13.8 over 6K), so he fattened it up a bit to give Greg a little more hip room on the street. Down in the low 13's the car still rolled 552/500 with a much more conservative A/F across the curve.

For those interested here is the flow data from Greg’s 205 heads tested on a 4” bore (on May 2nd no less!....lol)

Intake
Lift…..CFM
.200…..151
.300…..220
.400…..266
.500…..293
.550…..302 (peaked at .575 @ 306 CFM)
.600…..301

Exhaust (w/ 1.875 pipe)

.200…..129
.300…..190
.400…..228
.500…..242
.600…..248

Note how strong the exhaust port flows after the chamber and light porting work….It’s close to 200 CFM (more than a stock head’s peak flow) by .300 and as early as .400 matches a lot of aftermarket heads average .600 number at 228 CFM. Due to this situation and the very high overall exhaust to intake ratio (82%) a single pattern cam (244/244) was obviously a good choice here and proved effective on the dyno.

A quick summary of this combination is as follows because I know a lot of you will be asking…

403 Shortblock (built by LME)
11.6 CR
AFR 205’s with reworked 4” bore chambers and some light porting in key areas
Ported FAST 90 / Ported GM LS2 TB
Custom Comp Cam 244/244 XER lobes 113 LSA
ASP Underdrive pulley
Mezeirre EWP
Kooks 1.875 headers (with Cats btw!)
QuarterMaster clutch/flywheel assembly
M6 driveline with stock rear gears (3.42)
SVO “green top” 42” injectors
Vortex Ram air CAI (85 mm)
Nology ignition wires

Thanks to LME for all their hard work on the short….Mike and crew @ Haddad Motorsports for the install and “storage”….LOL, and George Lara who put all the pieces together with a killer tune. Look for some idle clips and video footage of this combination in the near future as well as an article in one of the Vette specific Mags….

Regards,
Tony Mamo

Originally Posted by 408zo6

Dynoed my car today at New Era Performance Parts and it made 551rwhp and 490rwtq, mods in sig. Tomorrow we will be spraying a 300 shot . I'll post later to tell you what it mades on the squeeze.

Originally Posted by studderin

some quick ones, I know were posted



break-in tune
1st sg 100shoot 665hp 661tq
+2nd sg 200 at 5K 845hp 786tq

https://ls1tech.com/forums/showthrea...&highlight=408


2nd. M6 T/A. forged 400cid, hellion cam, stage II Patriot heads (worked over LS6's) BBK intake and BBK 80mm TB, SLP exhaust, UD pulley, Ram powergrip HD. 483 HP 458 TQ. lookin forward to sprayin it. tuned my Mike@newEra
http://i2.photobucket.com/albums/y18...7builds020.jpg

SS M6. 402 LME motor, L92 heads, L76 intake, 239/246 .600 lift 114 lsa, Nick Williams TB, Ram powergrip HD, Stock cat back. 505 HP 477 TQ through the cutout..tuned my Mike@newEra

Originally Posted by 98Z28CobraKiller

I like the ones that show the 1/4 ET and MPH.

10.71 @ 124.9 w/ a 1.5 60'

LS2 408
225 AFRs
11.8:1 Comp
244/248 612/615 111(+3)

And last but very important is 3700 lb race weight.

I am geared for the big shot so my 3.73's arent ideal on the 28" DR's for motor passes.

Originally Posted by junior28570

cobrakiller: Awesome track #'s NA!! I didn't notice your hp/tq #'s anywhere .. what are they?

Originally Posted by Mike TexaSS

This is a car we just finished yesterday.

2000 C5 Corvette
408 LS1 11.4.1 Compression HK Racing Engines
Greg Good Stage MEGA HP LS6 Heads 2.10 Valves
Custom Solid Roller Camshaft (Specs per Greg Good) around 250/260
Jessel J2k Rockers
Greg Good Ported FAST 90mm
Kooks 1 7/8 to 2" Headers
3" X-pipe
Textraila Exo Skel Dual Disc Clutch
Six Speeds Inc Stage 3 T-56 ( You da man Joe!)
DTE Stage 3 4.10 Rear End
19" HRE Wheels

MAFless Tune

This dyno is through open x-pipe. Through a B&B Triflow Catback it makes 578 RWHP!

601 RWHP 513 RWTQ SAE

Originally Posted by Mike TexaSS

I finished my new setup! This is my personal daily driven Corvette. It made what my old 402 did but this one is smoke free!


402 LS2 11.1 Compression-HK Racing Engines
TEA AFR 225's Flow 345cfm
249/255 .640 .640 110 LSA
Greg Good Ported Fast 90
Stock 1.7 Rockers (Sold my Jessels)
Kooks 1 7/8 Headers
3" X-pipe
Corsa Catback
Textraila Exo-Skel Dual Disc Clutch (Thanks J-ROD!!)
DTE 3.90 Rear End

Tuned with no MAF


This dyno is through cutouts with heavy *** 18x12 Z06 Wheels (70lb per wheel and tire)

541 RWHP 512 RWTQ SAE

Originally Posted by XtrmLS1spd

Car made 465 RWHP and 430 RWHP on a Superflow dyno.

Mod List is as follows...

Engine:
Performance Engineering Aluminum LS2 403 (4.000 stroke/4.005 bore)
Eagle 4.000 crank
Eagle 6.125 Rods
Manley Pistons (-14cc, 4.005)
Clevite 77 Rod Bearings
Clevite 77 Main Bearings
Chromoly 7.400 Pushrods
Stock GM Lifters
PRC LS6 stage 2.5 heads, 59cc, with 2.04/1.57 valves, PRC Springs
1.8 Harland Sharp Roller Rockers
SDPC Crane Cam 250/256 .580 .580 108lsa (actual lift is .614 .614 with the 1.8 HS Rockers)
42lb Green Top Injectors
FAST 90mm Intake
Nick Williams 90mm Throttle Body
SLP 90mm MAF
LS6 Ported Oil Pump
LS2 Timing Chain
ARP Head Studs
ARP Crank Bolt
Powerbond Pulley
LS1 Motorsports Lid (Black)
K&N Air Filter
Thunder Racing Catch Can
NGK TR55’s
Taylor 10.5mm Thunderbolt plug wires
Thunder Racing Coil Relocation Brackets
Poly Motor Mounts
Metco Valve Cover Breather

Transmission:
TH350 Transmission - built with racing clutches (~5,500 miles since rebuild)
TCI 3800 stall
Deep Transmission Pan
Transmission Cooler
Lokar dipstick
Performance Shift Kit
Hurst Pistol-Grip Quarter Stick Shifter
1998 LS1 Flexplate

Exhaust:
Hooker 1 7/8 headers
3 inch y-pipe
Dual Cutouts
Flowmaster Cat-back

Originally Posted by CamaroRick

My tuner had the car on the dyno, it's not completely dialed in, but the basic numbers are in, she made 467rwhp at 5600rpm peak torque was just under 460 at 4250rpm on the mustang dyno. was told it started to get some valve float at 6300rpms dont have a graph for that one tho. clutch master took a dump, gonna rebuild it tomarrow and try to get it back to the tuner for the little adjustments

The engine is a 408 11.9:1compression iron block, ballanced, coated bearings, 249/255 .612" .620" on a 110LSA tsp cnc'd l92 heads shaved to 68cc chambers, stainless heavy valves, patriot golds, caddy lifters, molly pushrods, doubble roller timing chain, highvolume oil pump, high pressure spring, stock rocker arms, kooks 1 7/8" headers, 3" y pipe to a single 3" hooker catback.

to tell the truth i was expecting more, was looking for a "bigger cam" in the l92 setup but it looks like it may need some work. overall im happy with the first results.
-1.8cc valve reliefs, 4.030 bore 4.000 stroke, .040" head gasket, 68cc chambers ~.01" above deck; this is with the hooker catback on the ypipe. The car is an m6 10bolt, spec stage 3+ clutch, stock l76 intake manifold

Originally Posted by donalr76

I went and got my car tuned at Xtreme Horsepowere in North Richland Hills on Friday. It put down 463 rwhp and 462 rwtq. I have stock induction which killed me on the big end the car stopped making power at 5800rpm. Time to invest in a Fast 90/90 or the new Weiland and I need a bigger MAF.
My car has a Texas Giant, PRC 5.3L, and full bolt ons. I would like to say thanks to Xtreme Horsepower for coming through with a great product (403 shortblock) and their Xtreme customer service. It is the best shop I have been to in the DFW. Thanks to Arvil and all the crew over there.