07 L33 prep for road coarse
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Teching In
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07 L33 prep for road coarse Trying to track down some reliable info on an 07 L33. It's the HO 5.3L optional motor.
I'd like to know if this year motor has any of the typical "weak" points of the other LS motors.
As far as power I would only do
LS6 manifold / throttle body
Sikky exhaust manifolds
Decent size cam (228r or slightly smaller equiv)
I'd be happy with 400-420 hp at the crank. Is that a reasonable goal for basic bolt ons and a cam?Will the short block be ok at that level? I'd really prefer to not get into it and spend the money elsewhere on the car.
I'd like to know if this year motor has any of the typical "weak" points of the other LS motors.
As far as power I would only do
LS6 manifold / throttle body
Sikky exhaust manifolds
Decent size cam (228r or slightly smaller equiv)
I'd be happy with 400-420 hp at the crank. Is that a reasonable goal for basic bolt ons and a cam?Will the short block be ok at that level? I'd really prefer to not get into it and spend the money elsewhere on the car.
Weak Points??? 
Teching In
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I am just about done with building my 2005 L33 for road racing. I also have a 2007 as a spare.
Yes the L33 has the same weakpoints as a Similar age LS motor. I plan to run a redline of only 6250 rpm with a normal shift point of 5000 rpm. Due to rules, my engine is mostly stock. On tear down we noticed #7 piston burned badly. We put forged Wiseco pistons in it and had to bore to a finish diameter of 3.800". Stock crank and rods, although a few rods had to be tweaked because they were undersize. All new race bearings, and a full balance job. I used a Melling 10296 oil pump, oil pan is still undecided. Heads are 799 castings with bronze valve guides and all new Manley valves for durability. Compcams springs, retainers and rocker arm trunions. Camshaft is stock due to rules. New timing chain. Final compression ratio is 10.5. A key aspect of the rebuild is ARP main studs, head studs and rod bolts. Rod bolts are a key weakness. Pay attention to steam venting on heads. Valve springs should also be a consideration.
Be careful in selecting an LS6 manifold, it may be too much depending of your specifics. I am using an LS1 and also Corvette cast iron exhaust manifolds. I would prefer to run a larger cam and long tube headers but have to be careful with my mods and HP or I will be punished by the technical inspectors.
Yes the L33 has the same weakpoints as a Similar age LS motor. I plan to run a redline of only 6250 rpm with a normal shift point of 5000 rpm. Due to rules, my engine is mostly stock. On tear down we noticed #7 piston burned badly. We put forged Wiseco pistons in it and had to bore to a finish diameter of 3.800". Stock crank and rods, although a few rods had to be tweaked because they were undersize. All new race bearings, and a full balance job. I used a Melling 10296 oil pump, oil pan is still undecided. Heads are 799 castings with bronze valve guides and all new Manley valves for durability. Compcams springs, retainers and rocker arm trunions. Camshaft is stock due to rules. New timing chain. Final compression ratio is 10.5. A key aspect of the rebuild is ARP main studs, head studs and rod bolts. Rod bolts are a key weakness. Pay attention to steam venting on heads. Valve springs should also be a consideration.
Be careful in selecting an LS6 manifold, it may be too much depending of your specifics. I am using an LS1 and also Corvette cast iron exhaust manifolds. I would prefer to run a larger cam and long tube headers but have to be careful with my mods and HP or I will be punished by the technical inspectors.
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Joined: Mar 2014
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From: Ohio
Trying to track down some reliable info on an 07 L33. It's the HO 5.3L optional motor.
I'd like to know if this year motor has any of the typical "weak" points of the other LS motors.
As far as power I would only do
LS6 manifold / throttle body
Sikky exhaust manifolds
Decent size cam (228r or slightly smaller equiv)
I'd be happy with 400-420 hp at the crank. Is that a reasonable goal for basic bolt ons and a cam?Will the short block be ok at that level? I'd really prefer to not get into it and spend the money elsewhere on the car.
I'd like to know if this year motor has any of the typical "weak" points of the other LS motors.
As far as power I would only do
LS6 manifold / throttle body
Sikky exhaust manifolds
Decent size cam (228r or slightly smaller equiv)
I'd be happy with 400-420 hp at the crank. Is that a reasonable goal for basic bolt ons and a cam?Will the short block be ok at that level? I'd really prefer to not get into it and spend the money elsewhere on the car.
What do you mean as far as weak points? The 5.3s are very stout motors, especially the ones with the 4th gen rods like the L33. Rod bolts are not the weak point unless you plan on revving to 7000+, which you won't need to with a cam just big enough to get you into the low 400s on power. HUGE power has been made on the stock 4th gen rod bolts as long as RPM is kept in check. Same goes for the mains. Head studs are definitely optional at that power level. You wouldn't even have to remove the heads if you had a good core. Cam swap, tune, and go.
They didn't come with a rear coolant crossover, though, so I'd make sure to convert to a 4-corner system for road racing.
