853 heads??
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Teching In
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853 heads?? i have an extra set of 853 heads, i am thinking of porting a set on my own. about how much power could i gain from doing this? is it worth the time or just sell both sets and buy some 243's?
853 heads are pretty crappy they require a graphite gasket which limits your gasket options and the flow is horrible. For the money a ported set of 241s or stock or ported 243s can be had for a reasonable price.
To give you an opinion the opposite direction ( read as: TIGHT AZZ) I was going to do the same thing, and also weld up the thin spot on the gasket surface and have the heads milled .035 to bump compression a little and allow me to run MLS gaskets. So no, your not crazy. I could be wrong but my understanding is the main difference between, 853, 241, and 243 is the finish of the walls due to the way they are produced, I am sure there are other minor differences.
I HTH
Mark
I HTH
Mark
TECH Enthusiast
Joined: Jul 2007
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From: Calgary Alberta
Yes 806, 853, and 241 are technically all the same, I suppose the 241's were somehow made better then the older heads. I know the 853's have perimeter bolt pattern for the valve covers. As the others are center bolt design.
799/ 243's are both the same heads except the springs and valves are not the same.
I have 799 heads myself. Works good even on stock heads to make some more power. But ported heads will always do better when done correctly.
I'm pretty sure all of the older LS1's used a graphite gasket... you can replace those old graphite gaskets with the new updated GM steel layered gaskets. That's what I did. In 2002 or 03 is when they changed to the steel gasket.
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806s, 853s and 241s all have parctially identical runners, main difference like said is the valve cover bolts on the 806's. With that said, when expertly ported like some AI 241's, they could make some serious power, nearly as good as ported 243's but much better than stock 243's.
Hand porting is extremely time consuming, figure 25-30 hours doing it the firsty time plus needed tools. A good hand ported set of 806/853/241's could give 30rwhp though. If you want to save a ton of time and research for a little more money than just pick up some $1000 ported 243s.
Hand porting is extremely time consuming, figure 25-30 hours doing it the firsty time plus needed tools. A good hand ported set of 806/853/241's could give 30rwhp though. If you want to save a ton of time and research for a little more money than just pick up some $1000 ported 243s.
Last edited by camz28arro; Dec 6, 2010 at 11:27 AM.
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Verdad Gallardo 853 aren't perimiter, they were on my 99 vette motor, and were swapped with 241's.
From what I have seen, and I understand why, you shouldn't run MLS gaskets on 853 heads due to a thin spot where the headgasket seals, it looked like GM wanted to give a spot to lift the head off with a prybar, so they made an indention that creates the narrow spot in the gasket. The MLS gaskets don't like to seal on this thin spot.
Mark
From what I have seen, and I understand why, you shouldn't run MLS gaskets on 853 heads due to a thin spot where the headgasket seals, it looked like GM wanted to give a spot to lift the head off with a prybar, so they made an indention that creates the narrow spot in the gasket. The MLS gaskets don't like to seal on this thin spot.
Mark
Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
806s are perimeter, 853s are center bolt.
Thread Starter
Teching In
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thanks guys a weeks worth of work on the 853's is worth about $700 to me so i think i'll sell both sets and get some ported 243's. should i be looking for a set from a certain company or should they all be ok, or which ones should i stay away from? i'd like to get this car running high 10's low 11's.
