View Full Version : 408 with stage 3 ls6 heads dyno numbers

11-14-2011, 08:58 AM
I have a 408 iron block in a 2001 ws6 Trans am that made 460 440 thru a 12 bolt. My setup was stage 3 ls6 cnc'd heads, Texas giant cam, 1 3/4 stepped to 1 7/8 lt headers, and full bolt on's.

After talking to Jason at Lucky speed and performance, he seems to think that switching to a set of cnc'd ls3 heads and a custom cam and their in house tune I should break the 500 rwhp mark. So I have purchased all the necessary parts and am currently waiting on them to come in. Once they are installed I will update you with the new dyno results.

11-14-2011, 11:49 AM
What are your bolt ons?
pulley, auto or s speed?
locked or unlocked?
intake setup?
exhaust x? cats?
fuel setup?
I ask because there is one my way that is over 500rwhp 480ish rwtq.

11-14-2011, 11:26 PM
Need more information about your setup like ssdungeon stated.

Who did your stage 3 heads?
What injectors?

11-15-2011, 04:11 AM
Even if it doesnt make 500rwhp I bet itll still be faster at the track then your current setup is. Step down a few sizes from that Texas Giant cam.

11-15-2011, 09:57 AM
It's an M6 with full bolt-ons, underdrive pulley, off road Y-pipe with SLP catback.

11-15-2011, 10:07 AM
I'm a cathedral fan personally, depending on who did the st.3 port on your 243's will determine if you see gains on the LS3 heads. A properly spec'd cam needs to be used for the LS3 top end as well. Those huge runners and intake valves don't need a huge intake lobe to fill the chamber on a 408.

You never mentioned your intake setup on the 243 heads?

11-15-2011, 12:51 PM
I think he was running an LS2 intake.

11-15-2011, 01:01 PM
Sorry guys, Yes it was buget build. I had a ported ls2 intake, a 90mm tb, slp maf, slp lid, 1 3/4" stepped to 1 7/8" headers, underdrive, and stock rocker arms.

11-15-2011, 01:04 PM
I have new cnc'd ls3 heads, ported factory ls3 intake, 101mm ls7 maf, 105 lid, custom grind cam, and 102mm tb.

11-15-2011, 01:05 PM
After x-mas I buy some ls3 roller rockers and a new set of tsp 1 7/8" lt.

11-15-2011, 11:06 PM
That LS2 intake manifold was probably holding back a bit of power on your cathedral port setup. A FAST setup would've definitely been beneficial on a stroker motor with a huge cam like the one you were running. However, the LS3 topends seem to work wonders as well when setup correctly. Good luck...

11-15-2011, 11:45 PM
Sorry guys, Yes it was buget build. I had a ported ls2 intake, a 90mm tb, slp maf, slp lid, 1 3/4" stepped to 1 7/8" headers, underdrive, and stock rocker arms.

The SLP MAF is it a 78mm? The rocker arms arent holding you back much but as everyone has said you are leaving a lot on the table with your intake. Also do you have stock injectors?

You can definately spend a few grand on heads and a cam but if you dont handle the basic supporting mods I think you may be even more dissapointed.

Not sure what your answers will be to the questions above as long as your injectors are efficient at least 36lbers and at least an 85mm maf not the stock 78mm slp maf. I really think you can be within a few HP of 500rwhp with that setup fast 102 or ported fast 90-92mm intake, and a good solid tune.

Those numbers are good but I really think you can get more bang for the buck by tweaking what you have over a H/C swap. Because you still have to cover the basics mentioned in most cases.

Ha I rearead the initial post... it seems you already purchased the stuff. I am sure Lucky has a special sauce formula for ya. Good luck with it and definately post the results. :cheers:

Plus you get to sell the cam and current heads so its sorta a win win.

11-16-2011, 09:09 AM
I have ford green top 42 Ib injectors. The SLP maf was a 85mm and was acting as a limitation on the air flow. I agree that the intake was leaving a lot on the table. The main reason for running the intake was for the n2o. The intake is a Dave’s n2o money maker. The largest limitation was the small runner heads. The heads were stage 3, but were 215 runner heads.

11-16-2011, 03:54 PM
a set of tfs 235 or afr's and ported fast intake would have got you over 500 changing the intake might have got 20+ you should have done that before buying heads,cam,intake,tb,maf,lid