josh2002-ws6

iTrader: (98)

I have a 2000 SS that has 350k miles. The drivers side head has now thrown 2 spark plugs in the past 6 weeks. They are stock 241's. I'm pretty sure they are just worn out from the mileage on the motor, it is 100% stock. Instead of putting another helicoil in I am just gonna swap the heads out with replacement lower mileage ones. I can't seem to find that many low mileage replacement 241's but have found a few 853's. If I switch, do I need to change or look at anything else? The car is staying stock, so don't suggest looking at anything else. Thank you.

A.R. Shale Targa

iTrader: (2)

If going through all that work, I'd pop some new lifters in there and a set of stock unmolested 243/799 heads

HCI2000SS

iTrader: (2)

Exactly!

Tim john---

I do not have the mileage Josh has but am curious as well. I have a stock 2004 GTO LS 1 with the stock/factory 241 cylinder heads on it, will the 243's be a direct bolt on, I mean will everything else fit, align and perform as intended. (just do a head swap) Engine is factory stock. Thank You.


Tim john---

farmington

iTrader: (14)

as long as the heads haven't been cut on the decks you're good to go. if they have been cut in the past might need shorter pushrods

Darth_V8r

iTrader: (4)

If you put the 243 on you can use MLS head gaskets. If not, use the composite gaskets. There's a notch on the 853/241 heads that won't deal with MLS

kinglt-1

iTrader: (26)

I posted the same thing then deleted it because of the snarky last sentence. "don't suggest looking at anything else"

A.R. Shale Targa

iTrader: (2)

I thought the casting notch was only on 97-99 perimeter bolt v/c styles ??

A.R. Shale Targa

iTrader: (2)

Kings tend to be a bit snarky cuz; well......they're kings.

Darth_V8r

iTrader: (4)

nope. I have center bolt style. It's on them too. And into some 2000 models. That's why I mentioned it. OP should look for the notch and purchase gaskets accordingly

Tim john---

What kind of performance gain could one expect with the swap from 241 heads to the 243's, all else being factory stock on a 2004 GTO LS 1 engine sans Hooker/Holley Blackheart mid length stainless steel headers. Being the compression would go up a tad would that be an issue w/ fuel, computer tune as is ? Would the 2004 LS1 GTO fuel rail covers still fit (2004 is different than 2005/6). Thank You.


Tim john---

Darth_V8r

iTrader: (4)

You'd gain 10-15 hp and about 1 mpg from the compression. Tune will be ok, but you'd gain from tuning *** swell

Tim john---

Thank You very much Darth, appreciate you taking the time.


Tim

RPM WS6

iTrader: (3)

1998 was the last year for perimeter bolts (806). '99+ (853/241) are center bolt.