I would say the 408 with a small cam this will give you near stock sound with over 420hp to the wheels, it will have better street manners because the power will come in sooner. Also there is more potential power down the road with the 408 if at some point the current power level isn't enough and im sure it wont be enough.

 

you can have a big cam b/c once you go with a bigger cube it will move your power down low anyways

 

I say it all depends on how much you are willing to spend in total. I'd go with top end if you aren't too serious about dropping lots of money into it. You can get some ported LS6 heads for like $900 that flow awesome numbers and just talk to a good place that sells cams like thunder to pick out one that works best for you. You should easily be able to get WELL over 420 rwhp with a setup like that with good bolt-ons and a good matching cam.

If you are willing to go the distance then go all out w/ and get an LSX block (if you have 6-8k laying around to set it up)! I want to see every F-body possible burning almost every car on the road 10-20 years from now. Especially since there won't be another F-body...

 

408 and stock top end with spray. keep the revs down with the stock cam and spray it, should last a very long time taking what ever you spray at it.

 

I voted 408 because I just tore into my engine (90K miles NO ISSUES) and found metal shavings and pitted cam bearings, so now I have to save up again to rebuild the short block. I'm leaning towards the 383 strocker myself.

 

Earlier someone suggested to rebuild a LQ4... Why not just get a used LQ9? You've got higher compression and they sell in yards for like $1500 complete! Throw the SLP L92/L76 intake kit on it for another $1600 or so, then a cam kit for $600. So, after you purchase your 90mm TB and sell the electric TB that the kit comes with you'll be under $4000. I would imagine some really nice numbers for dirt cheap! Plus, you've got a pile of used parts on your old LS1 and LQ9 that you could sell, like intake manifold, heads, blah blah...

 

where do i get an lq9?


ARD said they head a 6 litre iron block they were going to use. how do i know if it is a lq4 or lq9?


Jay is getting me a 408 with custom cam installed (and tuned of course) for just under 5 Grand. Then i plan on puting a 90/90 on it.

 

LQ9s have flat top pistons, but everything else is the same as an LQ4. LQ9s came in Escallades and Silverado SS's. The carcraft article where they made 550hp with a 6.0 and L92 heads was a LQ9... because you can see the flat tops in the picture.

 

what year was the lq9 used in the SS's?

 

Pretty sure every 6.0 SS silverado had an LQ9. You would probably have better luck looking it up under the caddy though, because there are more of those in bone yards than SS trucks. The last one that I priced was $1700 from intake to oil pan with about 70k miles on it.

 

im going to bring this back up. hoping for some new input.

 

My big debate is weather or not to buy a used LQ9 for ~$1500 or spend $3500 or so on a 408 short block. One is cheap but has stock internals and lots of miles... the other is new and stout but more than twice as much!

 

One big thing that you ought to ask yourself is how many more miles do you plan on getting out of the LS1? Mine has over 100k and I'm not planning on going over 130k with it. Plus... Aftermarket heads are EXPENSIVE!!! L92 heads are DIRT cheap...and kick butt. There is no better bang for buck head... but you have to have a 4" bore. So you need to go to an LS2 or LQx for that option. Me... I'm building my plans around those heads... Why? Because they're cheap and they flow like crazy.

 

Im going to go ahead with a new 408 rather than a stock lq9 that is used. Im only going to do this once so i might as well do it right. if in 2 years i want to go 300 shot or procharged i dont want to have to pull the motor again.