Wondering before I start my new project.

 

ive heard that the ls6 is better than the ls2 and i dont think the ls3 will work with the cathedral port heads. I think it only works with the l92 heads but dont qoute me on that. So whats the project?

 

I will.

The above is correct.

 

Well Its gonna be a cheatr cam with ls3 heads, unknown intake at the time but I'm trying to keep my motor up to date.

 

Any reason your tryin to use LS3 heads??

Stock for stock the LS6 is the best on your list. But a ported LS2 intake from ls2portworks can flow on par with a stock FAST 90. Unported it isn't worth the swap though. And unless you can buy one already ported for a damn good price a Fast 90 would be within reach after buying a LS2 & paying for the porting.

 

You're going to need a 4.00+ inch bore to run the LS3/L92 heads. If you're running a 346 the point is moot as far as the LS3/L92 heads.

 

L92/LS3 Heads go with the L67/LS3 Intake only..

Any Cathedral Port Head I would go with an LS6..

 

Ummm, no that isn't true. Stock for stock the LS3/L92 heads outflow the LS2/LS6 head. The LS2 and LS6 head are the same casting. The LS6 head uses hollow stem valves which help in the stability of the valvetrain.

As stated the LS3 head needs a 4" bore to clear the valves. It is a square port heat verses the cathedral head of the LS2/LS6.

Robin

 

Ummm, in my second part of my reply I wasn't even refering to heads. I was refering to intake options which was what he was originally asking. Hence mentioning a Fast 90 in my post which everyone knows isn't a head option.

I asked about the heads & why he wanted to use them b/c it limits his intake options.

 

Ahhh, well I thought this was a head post. Really the LS3 or L76 intakes are better than people would let on. The guys that are complaining are usually big inch combinations. I had a L92 Engine with an LS3 intake on the dyno last week and it was within 5 horspower of the carb intake.

Intake really depends on your ultimate goals.

Robin

 

LS3/L92 intake can only be used with LS3/L92 heads, LS3/L92 heads will not work with LS1/6/2 intake because of the intake ports on the head.

 

Thank god! Those intake don't flow as well as the LS3,L92 or L76


Robin

 

Robin, I know you have access to a more reliable set of resources than the majority of the people on here. Do you have any data to support the claim other than comparable dyno numbers on similar combinations?

Not trying to call you out, just trying to separate facts from internet fiction.

 

LOL, which claim are you asking about? The eads? the intake? please clarify.

Thanks

Robin

 

You have to remember that most of the people complaining about intakes falling off are larger cubic inch combinations. I am testing 6.0 and 6.2 engines.

If it's about intake flow then that gets a little murky. The LS2 or LS6 intakes are better than the LS1. Most say that the LS6 has a slight edge over the LS2.

Now the LS3 and the L76 are designed for heads that flow 50 CFM than the LS2/LS6 on their best day. Even if the LS3 intake was a bottleneck (which IMO it is not) then you would have to really choke the heads. With the numbers that we are seeing from the LS3 and L76 that doesn't seem to be the case. Remember I am working with stock cube and stock compression engines.

If you have a 4" bore the LS3 head intake combo will flow more and with a stock cam make more power. Now if you want low end the LS2/LS6 deal will be a tad better in the low end.


Hope this explains my thoughts.

Robin

 

lol, I thought we had all agreed the thread was about intakes!

Thanks for your insight Robin, I appreciate it. Just so I'm sure I understand your first comment, are you saying that the big cube guys are complaining because they fall off sooner than a FAST intake, or because they fall off sooner than an LS6 intake?

Also, have you done any/much testing with FI on the carb style intake? Curious about comments regarding the inner 4 cylinders running leaner than the outer 4.

(Sorry for the threadjack btw.)

 

Robin, good info! I'm going to muddy the water a little bit more and I think it might be decent info to the OP too.

I have a 6.0 L76 shortblock I was going to bolt my AFR 205s and 90 Fast intake on. Would a L92 headed/L76 intake combo with the appropriate cam make more power than my AFR/Fast setup? Or enough to justify the swap?

 

i think Edelbrock will have a l92 Super Victor eventually

 

^^They already have the V. Jr. for them.

 

They did this comparison in hot rod or car craft a while back on a 6.0 engine. The ls3/l92 stuff made about the same hp as the afr fast 90 setup. If you already have the afr fast, then it would be pointless to switch. The article was to show dollar for dollar that that the ls3 was the best bang for the buck compared to the high dollar head inake set up.

Nick