The motor is on the stand and ready to put in. I have to finish remodeling my basement (wife's rules) before I can put the motor back in. Anyway, I was trying to figure out how much power it would make. Anyone care to make an educated guess? Here are the specs

6.0 Iron Block
Compression Ratio 12.5:1
Lunati 4" Crank
Lunati Pro Billet Rods
4.030 Diamond Pistons -2cc
Coated main, rods and cam bearings
LS2 Timing Chain
Mellings Oil Pump
Comp XE-R 244-248 112lsa cam
Comp R lifters
Cometic gaskets .043 thick 4.030" bore
Absolue Speed 241 Stage 2 heads flow 308@600
Stock rockers
FAST 90mm Intake and 90mm TB
Car is an A4 with the stock 10 bolt and 3.73 gears
Pacesetter Long tubes and TSP true duals

 

I would guess between 500 to 515rwhp.

 

That is what I would hope for through the A4.

 

That is very similair to the setup I have for my car, but I'm running a slightly larger cam and 5.3 heads. I'm hoping for over 500rwhp thru the 12 bolt.

 

500rwhp is my goal as well. My 408 has stage 3 heads, flow a bit more on 2.80/1.60 valves. C.R. is 11.3:1 and also on a 4l65e...

However, though your c.r. is up, i think that it might be "interesting" to achieve. I think that a more realistic number of 480-490rwhp is, imo of course, a more accurate guess. Trust me though, with 480rwhp your in the 10 sec. range...easy!!!!

I know, the drivetrain loss sucks but they sure do shift nice a fast!!!

good luck!! looks like we both have a chance to have 500rwhp 408 a4'z.....lets see who gets there first!

 

I see a lot of people are in the 11:1 cr range. How much more power am I gainning with the 12.5:1? Say a motor made 475rwhp at a CR of 11:1, what would the rwhp be on the same motor with a CR of 12.5:1?

 

Mine is 12.5 also. I'd like to have some opinions on this too.

 

Hot Rod magazine had TPIS do a flow and dyno test on the AFR 225's (and their own S3 LS6 heads) milled and unmilled on a 422 ci engine with Fel Pro 4.100 head gaskets. AFR 225 Unmilled compression was 10.3:1 and put out 607 hp @ 5900 rpm on their engine dyno. Same setup but with milled heads now at 11.7:1 compression it put out 624 hp. So just by bumping the compression up 1.4 points they gained 17 hp. But this was on an engine dyno and in the lower rpms the milled heads actually lost a couple of hp.

FWIW - I am running 11.2-11.3:1 compression on my LS2 402 and was thinking of milling the 225's but decided against it because I will be running 93 octane with no knock sensors. It's a A4 with a TCI 3800, 12-bolt (3.73's), LSX 90mm setup (ported), 244/250 .610 cam, 1-7/8" QTP's and ORY. I would love to see 500 rwhp, but realistically might see 475-480. We'll see.

 

This thread is becoming pretty informational, this is good. Seems like a lot of people are looking for the same info.

Just to throw this in there, my old setup was a 383 Stroker, AS Stage 2 LS6 heads, 11.5:1 CR, LS6 intake, ported TB, Comp 236/240 XE-r Cam, YT rockers, FLP headers, 12 Bolt 4.11's, A4 with a TCI 4400. It put down 460rwhp and 430rwtq

 

Rougly... how much does it cost to build your 408 shortblock,,,bottom end..??If you don't mind telling me.

 

I`ve got LME building me a 408 and a set of ETP heads 245`s going on it. I haven`t decided on a cam yet. Will have LSX90 set-up, kooks 1 7/8, and a 200 shot on her. Car in my sig is getting it. All the bolt-on`s and then some. I have A4 also with 12-bolt. I`m hoping with a good size cam we get 530rwhp and over 700rwhp on spray! Will let you know in 2 weeks! G-Force is working on her!!

 

Well you have a really nice starting point. On a good tune I think you should see between 490-515rwhp.

 

I think the heads are going to hold you back. 475 rwhp. I made in the 450 rwhp range with similar flow and a 238/242 xer cam in a a4.

 

The Heads may hold you back,but you may hit ur goal on a Dyno-Jet My 408 is under way right now just waiting on Heads.with ET 240's 11 Valve angle my Goal is 500 RWHP on a Mustang Dyno

 

ooooo look at that cool corvette in that picture

 

Hey ********, did the vid work??????

 

13.5 to 1 and a bigger cam. I made 520. TH 350, 12 bolt.

 

I say try a bigger cam for that bad boy, I would also guess right around 500 hp as well, maybe a tad below cause cam is kinda small.

 

if you move th cam up you'll also redue the power range of the motor.

ME, well, i know that i could make 500rwhp with a great tune, which im working on right now....but im more than happy with a 490rwhp n/a through a 4l65e a4. IF i swap for a th350, yes, i will see over the 500rwhp for example, but i'll loose the cruise unless oi get a gear vendor.

 

Check out HPE's 408 - $3995 - a great deal if you ask me. I am really happy with mine and will probably buy a second one in a year or so to have a fresh shortblock sitting on the stand at all times!