Affordable and reliable improved 5.3 build
Thread Starter
On The Tree
Joined: Feb 2016
Posts: 102
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From: Leeuwarden
I'd probably forego turning down the LS3 and LS9 valves in favor of picking up a pair of 243 heads milled to achieve a 10.5:1 compression with Cometic .040 head gaskets. The 243 heads flow very well out of the box, and you won't have to spend a ton of money on buying different valves and having them turned down. A valve job and some bowl work on the 243s should provide adequate gains if you won't be happy with simply milling the heads and bolting them on.
Because of the rarity of the 243 heads over here I can sell them for a good price. I'm planning on using this money for the 706 heads, because, at this point, I believe they have more potential. They have a smaller intake runner and smaller combustion chamber to start with..
I will remember the cometic head gaskets
I will reconsider the LS2 chain, thank you..
Thread Starter
On The Tree
Joined: Feb 2016
Posts: 102
Likes: 1
From: Leeuwarden
I've contacted Callies. They told me they can deliver the Magnum XL in any stoke between 3.600" and 3.700". Maybe they can also do this outside of this range, but I just didn't ask.
Next to this I've seen there are hypereutectic pistons with the .927 piston pin, but they are LS1/6 pistons. With a possible weight saving of 6kg or more, on the rotating assembly, maybe I will go 5.7 instead of 5.3.
I couldn't find the compression height at that moment however, but I will investigate it later on. Making the Magnum XL and LS7 rods work in an engine would be great.
Next to this I've seen there are hypereutectic pistons with the .927 piston pin, but they are LS1/6 pistons. With a possible weight saving of 6kg or more, on the rotating assembly, maybe I will go 5.7 instead of 5.3.
I couldn't find the compression height at that moment however, but I will investigate it later on. Making the Magnum XL and LS7 rods work in an engine would be great.
Thread Starter
On The Tree
Joined: Feb 2016
Posts: 102
Likes: 1
From: Leeuwarden
It's been a while ago, but recently I've talked my setup over with the father of a friend of mine. He drives the 1/4 mile in under seven seconds and knows what he's talking about. This conversation confirmed some things and made me rethink other things.
The first thing is the 706 head. He confirmed me this is the one I want, so in the near future he will be giving this babies bigger valves, a 8-angle valve job and more.
The next thing we talked about were the sodium filled LS9 valves. He told me they stopped using them and that people who do use them don't use a valve seal so the stem gets cooled better. This made me investigate the problems with the LS7 and LS9 exhaust valves and why the LS6 ones did work. I got all kinds of possible explanations however and got to the conclusion that I need to use bronze valve guides. Next to this I doubt the 706 heads will cool the stems enough or can be made to do so without getting issues with the emissions. This is why I ditch the idea of sodium filled valves.
Last, but nog least, he told me not to use coated pistons. They are great for a street car, but within racing conditions the coating will come off. Since I will be driving on the track and stip every once in a while, I won't be using coated pistons.
The first thing is the 706 head. He confirmed me this is the one I want, so in the near future he will be giving this babies bigger valves, a 8-angle valve job and more.
The next thing we talked about were the sodium filled LS9 valves. He told me they stopped using them and that people who do use them don't use a valve seal so the stem gets cooled better. This made me investigate the problems with the LS7 and LS9 exhaust valves and why the LS6 ones did work. I got all kinds of possible explanations however and got to the conclusion that I need to use bronze valve guides. Next to this I doubt the 706 heads will cool the stems enough or can be made to do so without getting issues with the emissions. This is why I ditch the idea of sodium filled valves.
Last, but nog least, he told me not to use coated pistons. They are great for a street car, but within racing conditions the coating will come off. Since I will be driving on the track and stip every once in a while, I won't be using coated pistons.
