243 ls6 head dyno results!!

[Siciliano15]

just wanted to post up some results i got at the dyno today. i know everyone including me likes to see dyno numbers and the mods it took to get there....

my main mods are in my profile but basically i have most bolt-ons plus 243 heads and still on the stock '98 cam.

before the heads i was running the stock 806 1998 heads and a frost mail order tune based on those mods. the numbers the car put up were:
332hp and 336ft-lbs SAE

now i installed slp 1.85 rockers, the 243 heads unported just slightly milled with dual springs & valve job, and updated tuning done by frost using email tunes with HPTuners. still stock cam. the new numbers are:
362hp and 364ft-lbs SAE

so overall with those two mods and the updated tuning I picked up 30hp and 28ft-lbs of torque.

[TLS_Addict]

Wholy crap!

That is quite a gain with just stock heads and just bigger rocker arms. What are the stockers? What you did is what I was thinking about. Increase the lift but leaves the cam the same other than that right? My 2000 Z28 and your 98 have the .49X lift cam right?

Nice numbers man.

[shady milkman]

most of that power is from the rocker arms and tune i would bet ..at least 10-15hp if not more ...the heads of course however play a big role in allow that tune to get more out of your engine...good gains for sure

[Firebirdjones]

The heads also bump the compression from 10:1 to 10.5:1 (stock for stock),,,,since they are milled (depending on how much) the compression should be even a tad higher than that.
I'm sure the better exhaust side on those LS6 heads helped as well.

Pretty interesting results for sure.

[Siciliano15]

thanks. the stock rockers are 1.7's and according to smokemup.com the stock '98-'00 cam specs are
1998 - 2000 Fbody
202/210 int/exh @ 0.05" duration
0.496" / 0.496" int/exh lift
116 LSA

so those rockers bring the duration to around 204/212 and the lift to around 540. definitely happy with these results. only other mods i have planned for this car is a 226EPS cam and a 3600 stall. i hope those will get me to the 420hp range I would be so happy

[LS2GTO]

Decent gains for sure but if my memory serves me well I think the stock cam in the 98 and 99 LS1's were slightly bigger than 01-02.

For a few bucks more an aftermarket baby cam would have been a wiser choice and yield higher gains than to go with 1.85 rockers. But then you'd be spending more in labor cost if you couldn't install it yourself.

[Firebirdjones]

From 97-00 the LS1 used the larger camshaft. In 01-02 the LS1 was switched to the smaller truck camshaft.

[Siciliano15]

the 1.85's were to compliment the heads and kinda hold me over until I have the funds and time to buy/install a cam and the necessary stall converter. converter is def going to a shop to get done so thats like a g-note right there. ill install the cam myself. so im gonna eventually sell the rockers and get an EPS cam in the 226/230 duration range.

[Firebirdjones]

Here is some interesting info for ya comparing LS1 heads to LS6 heads.

For starters, the LS1 heads have an intake runner CC of 200 and an exhaust runner CC of 70.

The LS6 heads have an intake runner CC of 210 and an exhaust runner CC of 75.

Right off the bat in unported form, the LS6 heads already have an advantage.

Here are some flow numbers on the intake side...

LS1
.200 137
.300 187
.350 207
.400 223
.450 228
.500 237
.550 242
.600 243

LS6
lift.......flow
.200 156
.300 204
.350 225
.400 243
.450 257
.500 268
.550 275
.600 278

Easy to see the LS6 heads are superior, and even at mid lift flow (.400) they beat the LS1 heads by 20 cfm. After that they really take off skunking the LS1 heads by 30 cfm.

I don't see an exhaust side comparison but I do know the LS6 heads have a better I/E ratio, and with 5 more CC's, with a D shaped exhaust port for a better short turn radius I'll bet the exhaust side also has comparable gains over the LS1 head.

[blackSS01]

Here is some interesting info for ya comparing LS1 heads to LS6 heads.

For starters, the LS1 heads have an intake runner CC of 200 and an exhaust runner CC of 70.

The LS6 heads have an intake runner CC of 210 and an exhaust runner CC of 75.

Right off the bat in unported form, the LS6 heads already have an advantage.

Here are some flow numbers on the intake side...

LS1
.200 137
.300 187
.350 207
.400 223
.450 228
.500 237
.550 242
.600 243

LS6
lift.......flow
.200 156
.300 204
.350 225
.400 243
.450 257
.500 268
.550 275
.600 278

Easy to see the LS6 heads are superior, and even at mid lift flow (.400) they beat the LS1 heads by 20 cfm. After that they really take off skunking the LS1 heads by 30 cfm.

I don't see an exhaust side comparison but I do know the LS6 heads have a better I/E ratio, and with 5 more CC's, with a D shaped exhaust port for a better short turn radius I'll bet the exhaust side also has comparable gains over the LS1 head.

Great info I wish I had flow numbers on mine since they were massaged a bit

[BAD_EFX]

Thanks for posting the flow numbers Firebird
The 243 heads are a bit more efficient and explains why you can't run as much ignition advace with them compared to LS1 castings. Stick the later Z06 cam in there and you'll have some really nice numbers and awesome stock driveability. I have an LQ9 (same port style as 243/LS2 with larger chambers) with the Z06 cam and less compression than you. With bolt ons I rolled 371/380 at the tires... so I imagine you'd roll close to 390.

[Firebirdjones]

Thanks for posting the flow numbers Firebird
The 243 heads are a bit more efficient and explains why you can't run as much ignition advace with them compared to LS1 castings. Stick the later Z06 cam in there and you'll have some really nice numbers and awesome stock driveability. I have an LQ9 (same port style as 243/LS2 with larger chambers) with the Z06 cam and less compression than you. With bolt ons I rolled 371/380 at the tires... so I imagine you'd roll close to 390.

You're welcome. An LQ9 with an LS6 cam? That ought to be a torquey little setup. I like the sound of that.