LS3 416 or sleeved 427?
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LS3 416 or sleeved 427? I am looking at getting an LS3 built, either a 416 or a sleeved 427. Naturally aspirated, just big heads and cam on pump gas.
Pricing is similar for both options. Is one superior to the other? My main concern is reliability/durability - does sleeving the block create any new possible failure points?
Pricing is similar for both options. Is one superior to the other? My main concern is reliability/durability - does sleeving the block create any new possible failure points?
sleeved blocks are great....i went through the same dilemma a few months ago before i decided on a sleeved 427, look at all the 418-427 ls3 builds, they are all 4.065 bore.....with a plastic intake they struggle to break 525 rwtq and usually are 575-590 rwhp, rare if they break 600......then go to corvette forum.....all those ls7 cars are basically breaking 600 unless they are running a baby cam, and 550 rwtq is pretty common......the main reason is the bore......that 1/16" extra bore is key......the bore makes more power, and the ability to now run ls7 heads makes more power......similar costs but much better results on the 4.125 bore side.....if you are interested i am selling an ERL resleeved 6.0.....should have the rotating assembly out of it in a week or 2.
sleeved blocks are great....i went through the same dilemma a few months ago before i decided on a sleeved 427, look at all the 418-427 ls3 builds, they are all 4.065 bore.....with a plastic intake they struggle to break 525 rwtq and usually are 575-590 rwhp, rare if they break 600......then go to corvette forum.....all those ls7 cars are basically breaking 600 unless they are running a baby cam, and 550 rwtq is pretty common......the main reason is the bore......that 1/16" extra bore is key......the bore makes more power, and the ability to now run ls7 heads makes more power......similar costs but much better results on the 4.125 bore side.....if you are interested i am selling an ERL resleeved 6.0.....should have the rotating assembly out of it in a week or 2.
If both are 4" stroke and price is comparable, 427 all damn day long. Even if you decide to run LS3 heads, they'll flow better on the bigger bore. If you can afford the cubes, get the cubes
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Sleeved blocks are hit or miss. Hard to explain. We both can send the same exact block to the same vendor and one block go be better/last longer than the other one. Blocks are kinda like cars... they can be the same but not the same. With that being said i would go 416.
It depends on your goals. If your going max effort then sleeve it and run LS7 head design. If your looking for a street runner and going to put some miles on it go easy on the cam and run the 416 w LS3 heads. The LS7 1.8 rocker geometry is very hard on valves and guides. They dont last nearly as well as the LS3 1.7 ratio will
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Joined: Apr 2012
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From: New Zealand
Darton sleeved all day long but it has to be done by someone who not only really knows what they are doing, they will take the same care on YOUR block. R.E.D. CA have a reputation for excellent sleeve work. If you use Darton sleeves you can use any block, I'd run a Gen IV only because it's newer with a few minor design improvements over the older cheaper 5.3's, but a 5.3 would be strong, cheaper, and suitable... and yeah, go 4.125 x 4 = 427 or even 4.185 x 4 = 440. I'm not a 454 fan due to the long arm but many swear by them.
Given the same attention to build quality - there is no strength comparison between a stroked LS3 and a Darton sleeved (esp a MID wet sleeve) LS3. Not only will the Sleeved engine make a few more ponies - it will keep a straighter bore and hold together longer. The factory bores move and that matters when you start pushing past 600rwhp and is one more reason why at some power level things break. LS blocks move around when under high stress - it's well known by race engine builders and why they prefer aftermarket blocks or will Darton sleeve if they have to use the factory block.
I agree with the earlier post - at 440 cubes a 250 degree intake @ 050 (tho I'd keep the exhaust close to that - not a big split) is going to rock, it'll be awesome.
Given the same attention to build quality - there is no strength comparison between a stroked LS3 and a Darton sleeved (esp a MID wet sleeve) LS3. Not only will the Sleeved engine make a few more ponies - it will keep a straighter bore and hold together longer. The factory bores move and that matters when you start pushing past 600rwhp and is one more reason why at some power level things break. LS blocks move around when under high stress - it's well known by race engine builders and why they prefer aftermarket blocks or will Darton sleeve if they have to use the factory block.
I agree with the earlier post - at 440 cubes a 250 degree intake @ 050 (tho I'd keep the exhaust close to that - not a big split) is going to rock, it'll be awesome.
Last edited by Bazman; Dec 12, 2018 at 01:49 PM.
Do what I did way back in 2002.......4.125 stroke and a 4.1 bore = 436ci. 7.1 Liter......LOVED IT. With crappy LS1 heads, LS6 intake and a stock TB, 11.3:1 compression.......made 500 RWHP and 505 RWTQ. Cam was 242/242 .610/.610 114 lsa...idled very smooth.
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Quality machine work is seldom inexpensive in my experience.
Taking an LS block and doing a quality sleevie install looks like it adds about $2,000 give or take to the cost of the block. With a shop like Race Engine Development or Bischoff Engine Service, if a sleeved block fit the budget, I'd go for it over a LS3/LSA block 416, for the reasons mentioned above. Who's doing the work and their attention to detail really matters.
If it's some generic vendor's sleeved block I stick with the LS3/LSA block 416.
That's my .02
Taking an LS block and doing a quality sleevie install looks like it adds about $2,000 give or take to the cost of the block. With a shop like Race Engine Development or Bischoff Engine Service, if a sleeved block fit the budget, I'd go for it over a LS3/LSA block 416, for the reasons mentioned above. Who's doing the work and their attention to detail really matters.
If it's some generic vendor's sleeved block I stick with the LS3/LSA block 416.
That's my .02
It depends on your goals. If your going max effort then sleeve it and run LS7 head design. If your looking for a street runner and going to put some miles on it go easy on the cam and run the 416 w LS3 heads. The LS7 1.8 rocker geometry is very hard on valves and guides. They dont last nearly as well as the LS3 1.7 ratio will
My sleeved LS6 block (by RED) back in 2002 went 173,000 miles without an issue.....until at 150 mph a piston got cocked in a cylinder and ended that party. But as mentioned
@99 Black Bird T/A ..... a quality job and you will not have an issue. So pay the best to do the work, like the guy who designed the sleeves in the first place.....RED.
.
@99 Black Bird T/A ..... a quality job and you will not have an issue. So pay the best to do the work, like the guy who designed the sleeves in the first place.....RED.
.
My sleeved LS6 block (by RED) back in 2002 went 173,000 miles without an issue.....until at 150 mph a piston got cocked in a cylinder and ended that party. But as mentioned
@99 Black Bird T/A ..... a quality job and you will not have an issue. So pay the best to do the work, like the guy who designed the sleeves in the first place.....RED.
.
@99 Black Bird T/A ..... a quality job and you will not have an issue. So pay the best to do the work, like the guy who designed the sleeves in the first place.....RED.
.
KW
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Joined: Apr 2012
Posts: 333
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From: New Zealand
True at normal wide splits and LSA's, but if you go for asymmetrical high intensity lobes (not extreme but faster ramps than normal), close the split (to build more tq instead of extending the rpm) and tighten the LSA to say 110/111 with intake around 108 (more TQ and cylinder pressure) it'll rip even at 11:1. Idle will suffer... so if that matters, go down to 240-244 and widen LSA. A good 250 cam will make 600hp in an old school Mopar 440 with stock head castings that are simply ported, on an LS they will do that at the wheels.