00 black ss

iTrader: (9)

What would be the difference in hp with stock 241 between stock 243 over my 853. What to know if it is worth getting the 243 for the extra few hundred.

BaddBird

iTrader: (6)

Only difference in the 853s and 241s is the casting methods. 243s have bigger intake runners and smaller chambers which will bump up your compression and flow better. As far as hp just a guess stock 243s over 853s maybe 20hp.

j-man

iTrader: (32)

With a MS3 cam I would think 20 is a good guess, stock vs stock. Of course getting the 243s worked up would yield more.

Jon@Texas-Speed

iTrader: (18)

I wouldn't waste your money going to a 241. However, the 243's will definitely gain you some power. I'm guessing in the 15-20 range on a set of unported heads. You can also, shoot the heads to us and have them ported before you put them on if you have a little extra cash. We can CNC port the heads and CNC valvejob them along with a light mill to square up the deck surface. You would be looking at $650 if you wanted to do it. Let us know if we can help!

Jon

00 black ss

iTrader: (9)

How much would this gain in addition to the 20 I'd pick up from them being stock

DNTMPME

Probably another 20...and more if you get a Fast...

Do Work Son!

iTrader: (1)

it only made a two wheel hp difference for me...... granted i with with a smidge different cam on the 243's. but i didn't pick up the gains i expected stock to stock.

BaddBird

iTrader: (6)

How did you bump up your compression half a point and only gain 2hp?

NemeSS

iTrader: (127)

somethin is off
i gained 25rw going from 241 to 243 on one car with ls6 cam and bolt ons car.
with updatd tune

Do Work Son!

iTrader: (1)

Hey,,,,, you tell me. I have been askin that SAME question for the last 7 months. the only thing i can figure is the original owner of the car fluffed his dyno numbers. i was running a G5X3 236/242 .600/.600 at 112, then i switched to a comp 232/236 .595/.601 at 114 with the 243's. off the spray i did 404 on 503. It ran a "reported" 402 off 502 on before.....

02*C5

iTrader: (1)

I just did a VR5 cam only exchange on a C5 ZO6 and it dynoed at 430/420 hp/tq. Those numbers came with stock 243 heads on the ZO6. You would never see those numbers with 241 heads even on an LS6 motor.

MonmouthCtyLS7

iTrader: (6)

Ive heard 15hp differance

IRONFIST

I just did this swap and the difference is considerable, the car chirps third much harder, and pulls away from my buddys 370z quickly.. were as before it slowly walked away.

I won't know the quarter mile difference until this summer.

printmanjackson

iTrader: (1)

what kind of cnc port job are you getting for $650? That's 30% cheaper than what most cnc jobs cost.

LTX355

iTrader: (15)

i would also like to know what kinda flow #s with the cnc. Or would it b wise to just cnc the 853s and save the money u spend on the 243s.

Dom

iTrader: (2)

No it's not. It's about $1k for most stage 1 jobs and that includes the heads. This $650 doesn't.

attaway

yeah it cost a good amount to cnc port 243 heads

c5formula

iTrader: (55)

i would also be interested in knowing what the difference would be between cost and HP gain between have the 853, 241, and 243 casting ported??

flintwrench69

iTrader: (11)

If youre gonna spend that kind of money on a port job, it only makes sense to start with a better casting like a 243 or 799 thats been proven to make more power. Sure 241s & 853s can make good power ported but not as good as an LS6 head.

LTX355

iTrader: (15)

not sure if thats the case thats all we had back in the day. old castings ported right r hard to beat. just look at the 5.3 head tsp offers compared to the ls6. flow #s r not far off. An ls head should have the same potential a 5.3 head has...