C_los54

I have a lq4 short block that I rebuild. And now it's time to buy heads was thinking of going with a ls3 top end. This is my first build and I just want to check with you guys on what's the best route to go. Factors being budget first and than perfomance. I have heard great things about 243's so please give me your opinions. Here's a little bit more info. The engine will be going in a 68 camaro with a t-56 6 speed. The car will spend 90% of its life on the street. This build is on a budget so I would like to buy used stock heads and also a used intake. My target hp number will be 450 crank and close to 400 rwhp. keeping as much power down low as possible. I will run stock fuel injection also. Had the block hot tanked and the cylinders cleaned up. Here's a list of what I've done.

Stock Pistons new rings
New cam bearings
New crank and rod bearings.
Ls2 timing chain
New stock oil pump

I'm in the process of buying all of the build parts so I have time to wait for good deals to come my way. Also ifanyone is running a stock lq4 bottom please post some info on your builds. Thanks.

allmotor1

id say for your goal 243s would be the better decision.

Tuskyz28

Your goal can be achieved with either head.
Hot Rod magazine took a 6.0 added headers and a tune.... motor pumped out 410 horses/440 ft lbs or torque at the crank. Another 40 horse can easily be gained with a small cam from a sponsor here.

Go with the 243 heads due to port design and cheaper cost also.

kainedogg

iTrader: (23)

243s or 799s for the win.

ls13ater

iTrader: (3)

L92

I have had a ls1 and a 6.0 both with 243's a few different cams and I love my new setup!

It a Lq4 with 0821 made 465/430 threw a 6 speed, went 6.8x @104 on motor, in a friends car, I have it back with a 4l60e in my car as a dd, it went a 7.1x @98 with a 2:73 gear on motor and a 6:75@103 on 125 with a slipping tranmission

C_los54

Thanks for the help guys. The only issue I have with the 243's is the intake. I can buy a ls3 intake/fuel rails/injectors for 300-400$. Ls6 intakes seem to be very pricey. But there's always ls1/2 intakes also. For the money it just seem to me that the ls3 top end gives me more room to improve power in the future.

HCI2000SS

iTrader: (2)

Either setup will make the power that you're wanting so it's really up to you

Tuskyz28

It's hard to say. You'll spend cheaper on the LS3 intake but you'll spend more on the LS3 heads also. So pretty much you'll break even cause 243 heads are cheaper than the LS3 heads also.

On the other hand I'll figure I'll share some info that might be useful upon your ultimate decision. The 243 will produce more torque over the LS3 up to 4000 rpm.... The LS3 will outshine the 243 head in the power department starting around 4000 rpm. If you decide on the LS3 head be sure to really have your ducks in row on cam selection... Most people tend to over cam them cylinder heads.

HISS

iTrader: (52)

It'll take a more aggressive camshaft to make 400 whp with cathedrals. Square port heads can be had for the same or slightly higher than 243/799 castings. One thing to factor with the ls3/square port setup is also throttle body cost. If you have to go aftermarket the budget price of the intake goes out the window. I think honestly either setup will work fine for what you modest power goal is. Either way plan to spend more than you initially intended.

hokeplaya05

iTrader: (3)

i plan on going with 243's on my SBE lq4 and getting a custom cam spec'ed for my setup (going in my 4x4 truck)

lawrenq

iTrader: (2)

I'm in the same boat as you an lq4 with ls3 top end, I found a good deal on 823 heads with a complete ls3 intake.
But the more I research it seems that I should have went with cathedral heads instead for a street car.

OutlawDrifter

iTrader: (9)

i've got an LQ9 with 317s and a futral motorsports f13 cam. .595/.585 230/232 and it makes 422hp through a t56 and an 8.8 rear with 4.10s.

so an LQ4 with 243s and the same cam should put out similar numbers.

Pocket

iTrader: (22)

I run rect port heads on all my 6.0 builds. Excellent power without even trying

If you do run cathedrals, skip the LS6. Aftermarket alum intakes out perform it at roughly the same cost - new. FAST composite intakes will blow them out of the water, but then again, they're double the price

Jadedbird

iTrader: (27)

An ls3 top end is going to be cheaper and make more power than a ls6 top end