you've got some of the best heads ever built for the small block!!! {243} try a cam first before the big$$$$ for heads and for headers and cam you might have to "custom tune"

 

Exactly. More deck & a ported Combustion chamber = less compression which is required for FI applications. If you are staying with NA then the Heads require milling to keep the combustion chamber volume less. If I recall 62cc will keep compression @ 11.1. 66cc will drop CR to 10.6 or so. Think the ratio is 5cc=.5 CR

 

JT - My 383 has a CR of 9.25 to I'm OK from that standpoint for upping the boost. Still not sure about the headlift issue, though but I guess I can always just turn the boost up to 17# & see what happens!! My guys says that, IHO, if I can keep detonation under control ( I have an ECS meth system plus Torco available ) then I can probably get away w/the additional boost provided I don't get on it @ every light ( OK, so every OTHER light!!! ). As long as the head just lifts slightly & goes back down then I'll be fine for swapping out the heads ( eventually ) for AFR's or the RHS ones U mentioned. I just don't want a catastrophic failure that will result in a rebuild!

Gene

 

Yikes Gene . . . .

 

John - Oh, c'mon now. Gotta have SOME fun & 14# just isn't enough to even make the F1-R break a sweat!! HA!!!!
I'll make a decision when/if I hear back from Paul @ AFR, I guess.

Gene

 

Talk to England Green a supporting vendor.

 

We've seen nice gains with our Stage 1 CNC LS2 Heads and Stage 2 Camshaft with other supporting mods; ie: longtube headers, x-pipe w/cats and cold air intake. We've seen gains of 135 + RWHP with our Stage 3R heads and Stage 2 Camshaft with stock intake manifold and throttle body.

Two examples can be seen in the following videos:

+100 RWHP

Stage 2 heads, Stage 2 camshaft

+132 RWHP

Stage 3R heads, Stage 2 camshaft

Both of these vehicles had great drivability and made great power, especially considering the cam isn't too wild!

My personal car (99 C5) picked up 120 RWHP with our Stage 1 Heads/Cam, LGM Lontubes & X-Pipe, LS6 intake, and Z06 TI catback.

Regards,

Rick LeBlanc
Livernois Motorsports

 

It was AFR's for me................

 

Manny - Yep, I'm kinda leaning toward the tried & true AFR's myself. Sent Stephen ( Grond ) a PM like JT said just for his input in the meantime.

MG

 

MG,

I still have that sh*t eating grin on my face every time i get on it, hope you find the combo that makes the power you want........

 

You'll like them. I have the AFR225's, had the chambers milled to 62cc and have a 10.9:1CR.

 

Jeff - So U're having no problems w/your D1SC running such a high CR? Maybe my 9.25 is too low. What made ya decide on the 225's over the 205's? I'm just wondering if the larger 225's intake runners & valves might make the motor too "peaky" for street use ( which mine will mostly see ). Of course, the torque stroke of the 383 coupled w/the 3.73 gears hasn't left me too disappointed thus far!!

MG

 

This is true, 243 heads are really excellent pieces even in stock trim and even more so when ported properly.
Actual dyno tuning is always a must when making big changes (ie: cam swap, heads and cam etc.) such as this, generally speaking a mail order tune will not cut it.

 

Wow, nice gains on the dyno. Any quarter mile/track results?

 

While I wouldn't say that flow numbers/dyno numbers are totally/completely meaningless, they really are merely starting points/measuring tools used in making a car faster out on the street/track.

 

MG

I think I may have put the wrong CR down, maybe it 10.6:1, I really can't remember. I went with the 225s b/c I knew I was heading for a SC down the road. Also my mod shop highly recommended the larger heads for the airflow. My car is my everyday ride and I have nothing but pleasure and smiles everytime I get in it.

Jeff

 

There is no "best head". There is a best combo, however, one where the parts selected all complement each other and the tuning is top-notch. That's how you get the 500RWHP NA cars. Also, cost doe not guarantee better performance.

Posted this a couple months back:

Ran across this VERY interesting online article by these guys in which they did an actual heads-up direct comparison of cylinder heads on an LS2. I think you'll agree in reviewing the stats that it brings into question the conventional wisdom regarding port size and its effect on performance, namely that smaller ports result in better torque, especially down low, but may not do so well on the top end. See the results for the AFR205 to see what I mean.

The motor is a GM crate LS2 that in stock form except for Kooks headers, made 402Hp and 437Tq in the dyno cell. 400Tq was available as of 3K rpm. As prepped for the head comparison, the engine was running a Livernois Stage2 cam: 232/236, .600 lift 114 LSA. Through stock heads, that combo made 500Hp / 449 Tq. That is the baseline. Here are the numbers.

......................................@3 000rpm...............Max
......................................Tq .........Hp.............Tq..........Hp

LS Cammed Stock Motor......400.......232............437. ........402

S2 Cammed Stock Motor
/Stock 243 (baseline)..........400.......232....... .....449..........500

Liv Stg1 243...220cc...........406.......232..... .......465.........502
AFR 205............................410...... .234............480.........547
TFS 215............................413...... .236............487.........552
Liv Stg3 243...220cc...........415.......237..... .......483.........545
Edelbrock.......225cc...........414..... ..237............480.........536

L92/L76 combo..240cc?.......407.......232....... .....494.........547

Note that the mild Stage 1 ported makes more 3K torque than the stock 243, despite the fact that the port has been hogged out to 220 from 210 in the process of porting. The Stage 1 heads have no combustion chamber work and they use stock valve sizes. Interestingly the stage 1 cam, a much more mild 218/220 .57x lift on 114, made 450 Tq and 494Hp, so just 6hp off peak power from the S2 cam, but with not nearly so much Tq loss down low. It actually gained 2Tq over the stock cam at 3K rpm. Something to consider when camming a stock-headed motor, even if you have bolt-ons. The only bolt on not present here was the FAST. One can ponder whether it might have given back some torque through stock 243s.

Personally, I am surprised at the results, because (1) all these heads are within single digits of each other across the rpm range (and that includes the budget heads) and (2) port size does not seem to have much correlation with Tq or Hp. Just look at the L92 results. With that cc, that head should be dead at 300rpm. It's not. Overall, I think the L92 head is revolutionary technology because it defies many of the assumptions regarding head configuration. And frankly, when price is factored in, which it always is, the L76 or ported 243s cannot be beat.

 

I was trying not to say much since I am not quite done tuning, but I just installed the TFS215s. I agree there is no best head only combo.
My current TFS setup kicks the living s*$* out of the Cartek setup I had. I can just tell the way the car takes off on top end its not even going to be close on the comparison. Data to follow soon...

 

He said best not cheapest.

 

Please show the time slips when you get them. I saw the same TFS 225 headed car making 506rwhp run 4 tenths slower with the same driver as a 467 rwhp geared cartek 4x headed car. Many people driving a car with delayed onset power at high rpms fail to be as fast on a track as a car with even and boring power that is consistent all the way through the power band. Many over cammed cars have this issue.

Cartek has so many heads at different prices that I would need to know a lot more about your prior set-up before labeling an outdated Cartek head as inferior to a current best from trick flow. You have the same cam for bot]h sets of heads??

I am sure it can happen but the fact is that the final performance is why people buy packages. If your car is faster I will quote the results in future posts when people ask for killer combo's. Right now I see no C6's with faster H/C times.

SOTP in high rpm, dyno numbers, and flow benches all have one thing in common.