Newbie Needs Help

[Defunct SO]

Mustang, feel free to give me a call if I can ever help. 817-703-3750, Billy
ls1 = 346 ci 5.7 345hp, '98 - '02 F-body
ls6 = 346 ci 5.7 405 hp ('02 and up) Vettes
Ls2 =364 ci (6.0) around 400 depending on application, Vettes, GTO
lq4 = 364 ci 6.0 lower compression 300 -325hp depending on application, iron block, work trucks, Hummers
lq9 = 364 ci 6.0 higher compression 345 in Silverado SS, Escalade, Denali, Vortec Max, iron block
ls7 = 427 ci 7.0 dry sump, Z06 Vette
compression on order ( I may be slightly off by memory)

10.25
10.5
10.5
9.5
10.0
11.0
The good heads off of Camaro/Trans Am are 241's, 64cc
LS6 heads are casting number 243; better flow and 62cc I think
#317 head are 6.0 heads. Same flow as LS6, buy have 72cc chambers (great for forced induction.)
I dont know the ls2 casting numbers
All of the heads need spring upgrades with much of a cam at all.

What you do really depends on your budget and hp goal.
A good budget motor is an iron block 5.3 bored out to 5.7.

The combo I am doing will yeild over 400rwhp; 6.0 iron block, 241 heads, decent cam, exhaust, tune. 243 heads even better, but you will pay more for the heads. 241s can be had for $150-$200. Fine on pump gas

All gen III motor you swap "just" about everything; heads, cam, covers, etc.

The 4.8 is a little bit of the red headed step child.

The iron block is about 80lbs heavier than the aluminum

Stay away from '98 f-body stuff. Different pcm, heads, etc.

5.3, 5.7, 6.0 all had same stoke crank, 3.64". 6.098 rods cracked powdered metal.

Lq9s have heavier rods. They have a raised bump on the beam.

Some do 5.3 heads on the LS1. Smaller chambers for higher compression. Fine on pump gas.

[Mustang54]

TRTTurbo -

Thank you so much for the info. That is exactly what I was looking for. That is the basics of this engine family and makes things a lot more clear.

We have a take out motor from an '02 Firebird. I think it is the older version before the common use of the LS6 intake and heads. We are checking block casting and serial numbers to make sure. We're looking to make 400 - 450 rwhp to accomplish our goals. At least that's what the math says we need to push this much weight at the speeds we are seeking.

It sounds like we need to find a set of the 243 heads, do some spring work, and select a good cam, headers, and intake to push it all through. That should at least get us in the balllpark, and we'll see where it goes from there.

Thanks again for the info.

[RedHeartbeat]

LS2 uses the 243 heads the same as the LS6 but without the sodium filled exhaust valves. The 2002 LS1 also will have an LS6 intake which is about a $350 item on the used parts market. The LS1/LS6 both have a 78mm throttle body while the LS2 will have a 90mm TB. The mentioned parts are interchangeable, except the obvious facts that you cannot put a 78mm TB on a 90mm intake and vice-versa. The LS6 is the best flowing, power building intake made from the factory for a 5.7L engine, 15-20hp higher than a 2001 or earlier LS1. The LS6 intake can be distinguished by the flat floor on the botton surface of the intake. If its not flat, its not an LS6 intake.