243 truck heads ??
243 truck heads ?? I have been reading alot on ls1tech and trying to research up on stuff. I dont like being some one who asks the same question thats been asked 100 times already because peeps are to lazy to do searches and read up. After reading tho I am confused. I read that if you put the bigger valve 5.7 or 6.0 heads onto the smaller bore 4.8/5.3 blocks that you have to notch the cylinders. I then read something like the gen 4 4.8 and 5.3's come with 243 heads. Then that these heads have same size valves that are on the big bore motors but they arent sodium filled valves.
Anyway I just bought a gen 4 4.8 out of a '07 silverado and the motor does have 243 in plain sight on the end of the heads. Does this mean that I have heads with bigger valves and bigger combustion chambers than a gen 3 4.8 or 5.3 would have? Also does this mean my block is notched from the factory to clear these? OR is this a case where GM got a little lazy with casting numbers and that a 243 truck head should never get confused with a 243 car head?
One more quickie: Do the 243 truck heads get a plain jane valve spring or do they get maybe ls6 style springs?
TIA: Jason
Anyway I just bought a gen 4 4.8 out of a '07 silverado and the motor does have 243 in plain sight on the end of the heads. Does this mean that I have heads with bigger valves and bigger combustion chambers than a gen 3 4.8 or 5.3 would have? Also does this mean my block is notched from the factory to clear these? OR is this a case where GM got a little lazy with casting numbers and that a 243 truck head should never get confused with a 243 car head?
One more quickie: Do the 243 truck heads get a plain jane valve spring or do they get maybe ls6 style springs?
TIA: Jason
The 243 combustion chamber is more efficient and they used them on the flex fuel trucks. It is a pretty good head if someone that know what they are doing ports them. I don't believe you have to notch the pistons and I don't think gm put valve relief pistons on 4.8's.
Not sure about springs. But if they are yellow then yes they are Ls6's. If your going to put a cam in it then just get rid of those springs anyways.
Hope it helped.
Not sure about springs. But if they are yellow then yes they are Ls6's. If your going to put a cam in it then just get rid of those springs anyways.
Hope it helped.
