243 heads on a 5.3
243 heads on a 5.3 A friend bought a motor from a salvage yard that has 5.3/4.8 on the back of the block with 243 heads and a 5.7 head gasket. If you run 243's on a 5.3 do you run a 5.7 head gasket or is this motor possibly been punched out to a 5.7.
Any idea the year of the motor? They started putting the 243's on the truck 5.3L's in 2007. Measure the bore to see if that engine has been bored to 5.7L specs.
Im having a 5.3L bored to 5.7L. This engine had 255K on the clock so it needed rebuilt anyway. I wanted the extra cubes to work with.
Im having a 5.3L bored to 5.7L. This engine had 255K on the clock so it needed rebuilt anyway. I wanted the extra cubes to work with.
Staging Lane
Joined: Oct 2010
Posts: 49
Likes: 0
Any idea the year of the motor? They started putting the 243's on the truck 5.3L's in 2007. Measure the bore to see if that engine has been bored to 5.7L specs.
Im having a 5.3L bored to 5.7L. This engine had 255K on the clock so it needed rebuilt anyway. I wanted the extra cubes to work with.
Im having a 5.3L bored to 5.7L. This engine had 255K on the clock so it needed rebuilt anyway. I wanted the extra cubes to work with.
i was pretty sure all BARE 243 heads are exactly the same. i mean, thats why they have the same part number, right?
i'm bout to pick up a set of 243 heads from an 07 5.3 DOD truck (i dont know what a DOD is).
edit - nevermind, i guess you were addressing his 5.7 head gasket question.
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Verdad Gallardo wait, am i reading this incorrectly? according to this, you make it sound as tho the z06 243 heads have a 5.7L bore whereas the heads the OP is talking about, which are 243 castings, have a 5.3L bore.
i was pretty sure all BARE 243 heads are exactly the same. i mean, thats why they have the same part number, right?
i'm bout to pick up a set of 243 heads from an 07 5.3 DOD truck (i dont know what a DOD is).
edit - nevermind, i guess you were addressing his 5.7 head gasket question.
i was pretty sure all BARE 243 heads are exactly the same. i mean, thats why they have the same part number, right?
i'm bout to pick up a set of 243 heads from an 07 5.3 DOD truck (i dont know what a DOD is).
edit - nevermind, i guess you were addressing his 5.7 head gasket question.
But since its a 2007 then it could go either way since GM put 243's on the 5.3l engines.
Great find!
Is the grand prix FWD or RWD? Im not up on the newer ones considering the last one i had was a 1981 RWD. If its a FWD then that engine is useless for a RWD application.
Do the car heads have a different bolt pattern for accessory mounts? If so then that would also be a problem for a truck application.
TECH Apprentice
Joined: Jun 2004
Posts: 317
Likes: 52
From: Charleston, SC
We are talking about truck/rwd car engines here. I think the 2007 year for 243 heads is strictly for trucks.
Is the grand prix FWD or RWD? Im not up on the newer ones considering the last one i had was a 1981 RWD. If its a FWD then that engine is useless for a RWD application.
Do the car heads have a different bolt pattern for accessory mounts? If so then that would also be a problem for a truck application.
Is the grand prix FWD or RWD? Im not up on the newer ones considering the last one i had was a 1981 RWD. If its a FWD then that engine is useless for a RWD application.
Do the car heads have a different bolt pattern for accessory mounts? If so then that would also be a problem for a truck application.
TECH Fanatic
Joined: Jul 2005
Posts: 1,685
Likes: 7
From: Beebe, Arkansas
The Gen III L33 aluminum block 5.3L has 243/799 heads. It had the 4.8L flat tops to boost CR because of the larger chamber of the 243. It was the high output motor. None of the iron truck motors had the 243/799 heads stock.
All 2007 and up Gen IV 4.8/5.3 use flat tops and the 243/799 heads.
All 2007 and up Gen IV 4.8/5.3 use flat tops and the 243/799 heads.
