what is the best route to get to 450rwhp with good street manners? I have an 02 z28 m6 with 177k miles. Would rebuilding the engine and adding a h/c package with bolt-ons be enough and still keep it driveable?

Or would i see better results with more cubes?

 

Why not a supercharger?

 

Get the best heads you can afford then get your cam.
I would look into afr/mamo heads if you can swing the money and a cam spec by Tony himself to achieve your goals.
If not that route I would look into the classafied for a set of TFS heads and then hit up Brian Tooley for a cam... might actually come out cheaper.
Both combos should make well over 450rwhp with a daily drivable cam that's easy on your valvrtrain.
Just remember the better your heads are the less cam you can run to achieve your power goal.

 

"Just remember the better your heads are the less cam you can run to achieve your power goal."

That is true. Also the supercharger route is another way to go.

 

Was originally hoping to do N/A (something about it just appeals to me)

I could do a supercharger, though wouldn't one (plus the stronger internals) end up costing more? Also, how well do they clear stock hoods?

 

450 to the tire is a walk in the park... Especially with an M6. Doesn't take a donkey-dick cam either.

Used AFR 205's @ 59cc (GM MLS ghead gaskets .051 compressed)
BTR Platinum springs w/ titanium retainers
Unported Fast 92
NW 92mm TB
Powerbond 25% UDP
SLP lid (it's a 4" neck... screw a flimsy FTP 98 or 104)
Stock rockers w/ trunion upgrade
My build took LS7 lifters and 7.4 hardened PR's (measured). (I'd go with different lifters knowing what I know now...)

You WILL NEED injectors, and 36#ers won't cut it. You want IDC at WOT to be just around 80%. I used White Bosch 3's from a V6 supercharger Pontiac GTP, Part # 0280155811. They're a GREAT injector, same as Corvette used in the ASA program. 42# at our fuel pressure of 58psi. Fast calls them a 36# and I have NO CLUE why. I came in at 77% IDC at WOT and Geoff said it was perfect.

Don't forget a clutch. My stock one tapped on the dyno, and still made 452/417. Came back 2 months later with a Monster stage 2 (which drives like SILK) and heavier 17x11's with 315's and put down 460/420.

Cam was an FTI HellRaiser 229/236 .631.631 112+2. That car hurt a lot of C6Z feelings. A LOT

 

By the way... My short block had 145k miles on it as well

 

Yes it will be more expensive. Like you I prefer NA. If you can budget it, MMS220 plus a 227ish cam would easily put you in the high 400's. The rest would depend on intake and header selection. Which you would also need to do if you haven't yet.

I think the factory rates engines on flywheel not rear wheel power. "436 HP" LS3 stock Vette dyno'd 350 at the wheels. That should give you an idea of how fast 450 rwhp is.

 

DR, I think injectors are rated on how much n-heptane they flow at 43-psi. I read that off both Bosch and dears whorls websites

 

True!!

I just like to call them what they are at OUR fuel pressure to avoid any confusion.

 

i hit close to 450 whp on my ls1 gto with afr 241 heads, fast 92,
nw 92 tb, 42lb green tops, ms3 cam, long tubes, etc... did dual
springs, trunion upgrades, and some other small stuff. running
a monster lt1-s twin disc.

you can definitely do it, and the car is an absolute hoot to drive !

good luck with your build.

 

thanks for all the replies guys, will definitely be going this route.

Whigham, how did you get the AFR 205s down to 59ccs? Just mill the heads? What CR did you have with that?

And what's wrong with the ls7 lifters?

 

With that many miles on the clock, I would think about refreshing the bottom end before spending coin on the top end. Just my 2 cents, but what do I know?

 

LS7 lifters will "work" but it's an OEM application. They really aren't designed for higher spring pressures and have failed in the past. Spend a little more and go Morel 5315 (I think that's the #)

I was at 11.7 cr with the heads and cam. They were milled to 59cc. Throttle response was EXCELLENT.

 

450 is going to take a good size cam. I have the 228R and im not even close to 450.

 

Already have that planned. Just trying to find a good machine shop near me that'll do quality work.

Were you still able to run 92 octane with that cr? I know dynamic is more important than static, but still.

 

I have 93 here. I never had any signs of knock or detonation at all, and Geoff had it set to "kill."

That being said, I never put anything but Shell or Chevron/Texaco fuels. RaceTrack, Luvs, Pilot, SAMs Club... No way in hell. Run a good quality fuel with as much octane as possible.

 

Did 455rwhp/415tq in my C5...hero run actually did 467/427.

Dart as cast 225's 62cc
G5x2 cam
FAST 92 un-ported
1 7/8" kooks/kooks x
Ti cat back

Like was mentioned above...450 is pretty easy, especially with an aftermarket head. Mine was a budget minded, generic combo(cam/intake/heads bought used, factory lifters, cheapo pushrods, 10.8:1 static comp etc). I lost nothing down low and above 3500rpm it ripped my stock ls6's throat out.

Id start with the best heads/intake manifold you can afford.

 

Truer words were never spoken.

 

Amen x2 ^^^^^^^^