Swapping from 241's to 853's
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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.
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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---
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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
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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.
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You'd gain 10-15 hp and about 1 mpg from the compression. Tune will be ok, but you'd gain from tuning *** swell
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