New to LS, have many questions, here are a few...
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Teching In
Joined: Dec 2023
Posts: 46
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New to LS, have many questions, here are a few... Howdy! I've been hotrodding and racing small block chevy motors for about 20 years. I'm currently racing a 2004 NASCAR in SCCA (amateur) road racing. I had a "claimer" build 383 in it that just popped and I threw in a spare short block I had in the shop to get back on the track. I'm looking to transition to LS3 over this coming summer so I'm starting to do research.
OK... onto some (probably easy) questions...
1) The CT525 and TA2 choice motors are both LS3 376 making ~530-540 HP peak. As race motors, they run up to 6800 RPM and have maybe a 30-40 hour maintenance interval. And apparently that's all on a stock bottom end, stock head castings, upgraded valve springs and an upgraded cam. Coming from SBC, I just have trouble wrapping my head around those performance numbers on a stock bottom end. Wow! So maybe the only question hers is... what's the catch? Is this thing just that good?
2) What is some rough guidance as to when a race motor may need to move up to a forged crank? When would a race motor need to move up from the stock powdered metal rods?
3) The TA2 motor specs 821, 823 or 5364 heads. From my googling, these all seem to be identical castings with only a difference in whether they have hollow stem intake valves. And perhaps setup with different springs from the factory. Is that correct?
4) The CT525 says it comes with "Cylinder Heads (P/N 12629063): LS3 rectangle port; aluminum “as-cast” with 68-cc chambers" - so that's a part number, not a casting number... is there a reference for translating this part number to casting numbers? Is it an 821, 823 or 5364?
5) Are there any differences in the engine rebuilding process between an SBC and LS3? I don't know what I don't know... so just wondering if there's something I haven't encountered before.
Thanks,
Sal
OK... onto some (probably easy) questions...
1) The CT525 and TA2 choice motors are both LS3 376 making ~530-540 HP peak. As race motors, they run up to 6800 RPM and have maybe a 30-40 hour maintenance interval. And apparently that's all on a stock bottom end, stock head castings, upgraded valve springs and an upgraded cam. Coming from SBC, I just have trouble wrapping my head around those performance numbers on a stock bottom end. Wow! So maybe the only question hers is... what's the catch? Is this thing just that good?
2) What is some rough guidance as to when a race motor may need to move up to a forged crank? When would a race motor need to move up from the stock powdered metal rods?
3) The TA2 motor specs 821, 823 or 5364 heads. From my googling, these all seem to be identical castings with only a difference in whether they have hollow stem intake valves. And perhaps setup with different springs from the factory. Is that correct?
4) The CT525 says it comes with "Cylinder Heads (P/N 12629063): LS3 rectangle port; aluminum “as-cast” with 68-cc chambers" - so that's a part number, not a casting number... is there a reference for translating this part number to casting numbers? Is it an 821, 823 or 5364?
5) Are there any differences in the engine rebuilding process between an SBC and LS3? I don't know what I don't know... so just wondering if there's something I haven't encountered before.
Thanks,
Sal
1) No catch it's an LS they just make lots of power on stock parts too!
2) Again lots of guys matter big power on stock bottom ends. If you're already in rebuild mode and plan on going all out with FI or nitrous then definitely upgrade the rotating assembly.
3) 821 and 5364 heads ports are the same. Casting shift and bowl cut for the seat after the biggest contributors to flow variation. 823's have a slightly smaller throat with a better radius on the short turn and a better transition to the valve seat
4) 821 heads
5) Lots of differences between a Gen 1 and Gen 4 SBC. Different main caps, oil pump is crank driven, thrust bearing in the middle to name a few
2) Again lots of guys matter big power on stock bottom ends. If you're already in rebuild mode and plan on going all out with FI or nitrous then definitely upgrade the rotating assembly.
3) 821 and 5364 heads ports are the same. Casting shift and bowl cut for the seat after the biggest contributors to flow variation. 823's have a slightly smaller throat with a better radius on the short turn and a better transition to the valve seat
4) 821 heads
5) Lots of differences between a Gen 1 and Gen 4 SBC. Different main caps, oil pump is crank driven, thrust bearing in the middle to name a few