Kawboom

I am skeptical of the claim of 700hp out of that 408, thats 120hp more than Texas Speed advertises in their 408. That's just not enough engine, cam or heads, or RPM. Whats more hooey is the claim of nearly 600 torques at the wheels.

When Katech built an as legit as possible 700hp 427 LS7 it didn't make 600 lb/ft of torque, and a 12-13:1 compression 468ci LS with Mast race heads and the biggest cam Comp made for it made 750hp on the engine dyno it only made 645ft/lb of torque, less than it would take to make a chassis dyno read 600. 440 stroker engines with big heads make 700 or if running well 750. This 700hp street 408 seems like a case of Happy Dynos.

02EBC5Z06

iTrader: (1)

Agreed. I would say happy dyno, hence why I asked if it was on a chassis dyno. Now if the thing goes and runs higher 130s in the 1/4, then I would say sure. I would say a healthy 408 with the compression, cam, and solid top end will be in the 650+ range to the crank.. Most likely in the 550+ crank torque range.

02EBC5Z06

iTrader: (1)

There are plenty of 650+ whp, sbe ls7 combos out there in c6z's. A handful in the 700 whp area as well. It really just takes the setup to not be afraid of rpm and compression, and giving it the air and cam that it wants to get there.

02EBC5Z06

iTrader: (1)

My issue is all of the lack luster 400-416 combos. There is no reason these motors should be making high 400/low 500 wheel, especially through a manual. I am building a 408 LS2/L76 based motor right now. I'm giving it around 13.5:1 and all of the rpm it can take (planning on the limiter being around 8400 or so and peak power around 7500). I see no reason this thing won't be 580 whp at minimum in my c5.

Kawboom

The reason is really pretty simple. They didn't invest all the money into the aftermarket everything it would take to make that power. A 480hp at the wheels LS3 with a set of factory heads, 10.5:1 compression, a hydraulic roller 230/240 camshaft, headers and rev limiter of 7200 not something to be ashamed of. Its a street engine, and running well at that power number. It will live like that for a long time.

As for an engine that could make 580 at the wheels, well that's probably right at 700hp at the crank, or 650 if its a hub dyno. A 650 or 700hp NA 408 is not something you get with factory parts. New crank, rods, pistons, and heads or a trip to the CNC machine shop to port the stockers will be necessary. Tunnel ram intake, 2" headers, 12-13:1 compression, alcohol or race fuel and a 250/260 solid camshaft is the requirement.

02EBC5Z06

iTrader: (1)

Right, I understand that. But it's just, you're spending the money to build a 400+ motor, it costs you no more to raise the compression in the pistons besides the fuel that might be needed. You could easily just leave the thing stock cubes and make the same 480 wheel.

01CamaroSSTx

iTrader: (3)

Horrible audio..We must take into account that not all dynos are equal and they all can be manipulated.