Im getting my tax returns sometime soon and am planning to throw some cash towards headers.

I am trying to decide between thorleys or AS&M.

Has anyone dynoed or raced with thorleys?

What about AS&Ms?

The thorleys are about $400-$550 right?
What about the AS&Ms, about $800? Are they worth ther extra $250+? Any before and after dynos or race results concerning either of these headers would be great to see!

I LOVE <img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" /> my truck and spent some serious cash on it already SO I dont want to give it the second best set of headers! SO what do you all think is the best way to go?

Also how much should I expect to pay for either set of headers? What about header coatings (ceramic, polished, etc.), which is better?

 

I've been searching aournd alot and the ASM's seem to be the route everyone gets awesome results with. If I do headers to the 03 it will be the ASMs and just do it right the first time and not leave any hp on the table. I have had a few customers requesting I carry them too.

 

I can't speak for the new trucks but the Thorely's worked VERY well on on the older trucks. I had a 90' 454SS that with Thorely's, gutted cats, cat-back, and Jet chip (crap) ran 14.6s in 100deg heat on 315/35/17s. Keep in mind those trucks only ran high 15s stock LOL.

Not that this helps you much but Thorely headers have been around for awhile. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Interesting info!

The thorleys definitely sound appealing BUT once again I just dont want to put the second best headers on a truck I have spent so much cash on! I think it deserves the best, as do all of our wonderful LS1 based trucks! <img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" /> to Chevy

Anyway I think I will do a little more research and contemplation before making my decision.

Also does anyone know about warranty issues?

 

While I can't give you an apples to apples comparison because I have never run a set of Thorleys, I can tell you that the ASMs kick a$$. I picked up over 20hp from mine. The only thing quality/warranty wise that I can speak of is that the ceramic coating on mine is coming off in a few miniscule places (collector area mostly). If you want to see some pics of them on my truck LMK, and I'll send 'em to ya.

 

I asked this question about two weeks ago looking for some dyno proof to support my decision and couldn't find any dyno pulls.

Don't know if this is beating a dead horse but I think you should look into The Other Guys headers.

http://www.theotherguysproducts.com

They are also in So Cal so you may be able to stop by their shop and forget shipping. They offer a lifetime unlimited warranty and should perform at least as well as the ASM. I don't have any dyno #'s to back that up but I just got a set of their titanium coated headers myself and they are the best quality headers I have ever purchased.

If being legal is important, TOG headers are CARB certified. I called ASM before I ordered TOG and they said that putting them on a CA truck wouldn't be a problem but I never saw a CARB order for them.