Iron or ls2 block
Thread Starter
Drifting
Joined: Jun 2019
Posts: 1,588
Likes: 149
From: California
Iron or ls2 block
I still get to decide between a iron or aluminum block 6.0s will be stroked to 402 and make 1200whp eventually my buddy makes 1200whp on stock ls7 sleeves are aluminum 6.0 block sleeves allot thicker than a stock ls7
AMP Racing
Joined: Aug 2006
Posts: 10,757
Likes: 589
From: Washington TWP NJ
2023 C5 of the Year Finalist - Modified
2017 C5 of Year Finalist
St. Jude Donor '09-'10-'11-'12
Punctuation is your friend....
If I were going to build a 1200hp street engine, I’d use a Darton sleeved Aluminum block.
Good luck with your build.
If I were going to build a 1200hp street engine, I’d use a Darton sleeved Aluminum block.
Good luck with your build.
Melting Slicks
Joined: Nov 2003
Posts: 2,155
Likes: 269
Don't need a stroker for 1200hp unless you have money burning a hole in our pocket. For 1200hp on a budget skip the 6.0 and get a 5.3L, gen 4 5.3L aluminum will be a good bit lighter than the iron block as well.
Siamese bore gen4 aluminum 5.3L are plenty strong, multiple have run 7 sec 1/4's and made a good bit more than 1200hp.
Siamese bore gen4 aluminum 5.3L are plenty strong, multiple have run 7 sec 1/4's and made a good bit more than 1200hp.
Melting Slicks
Joined: Nov 2003
Posts: 2,155
Likes: 269
LS2 will certainly handle it especially for only a year and be a good bit lighter. Most of the stock block stroker setups need to be gone through anyways after a year or more of abuse, they are rougher on the piston skirt.
Burning Brakes
Joined: Aug 2008
Posts: 855
Likes: 35
From: Katy/Houston Texas
Not saying it can’t be done. Been there done that got the t-shirt. Im just saying for longevity I would not use a factory made aluminum block at those power levels.
Melting Slicks
Joined: Nov 2003
Posts: 2,155
Likes: 269
He did say for only a year. But still some iron blocks have more problems than the aluminum ones, between thin cylinder walls and the non siamese bore iron blocks have been known to crack between the cylinders. Depends on blower vs turbos as well, seem a lot more main bearing wear from a blower yanking the crank snout around.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Drifting
Joined: Dec 2003
Posts: 1,755
Likes: 88
From: Pearland Texas
I did this a few times with Darton Sleeved AL blocks 402/408 and 427. Worked well for me for a-1200long while, but not for a lot of others that I know of. So its hit and miss. ANYONE telling you 11-1200 rwhp cars on stock blocks are unicorns. I've herd it all seen it all and its all BS. I'm just telling you the truth. Can it be done sure. Is is smart if you want to enjoy your car any? NO! I do love the Dart AL SHP blocks but pricey, but if you want reliability its my first choice. Now if your going to harp on budget then you can do all the stock AL blocks you want and lets compare your reliably. But hell what do I know only been doing this **** for ever and I beat on my car regularly so if you don't beat on it much then you might skate by on a stock small CI blocks. GL just my .02 of TRUTH.
Thread Starter
Drifting
Joined: Jun 2019
Posts: 1,588
Likes: 149
From: California
Always allot of variables and I appreciate your input but motortrend them selfs have done 1950hp on a four bolt my buddy has a lq9 408 with over 20k miles and he’s at 1300+whp with a rear mount turbo. If it last 20k miles I’m happy
Race Director
Joined: Jun 2013
Posts: 12,414
Likes: 1,750
From: DFW TX
I'm no expert but would go iron. I understand aluminum flexes something like 3x as much which puts huge stress on everything else. The irons blocks were way overengineered to go 100's of thousands of miles in commercial vehicles which are beat on every day - they are tough.
Melting Slicks
Joined: Nov 2003
Posts: 2,155
Likes: 269
I did this a few times with Darton Sleeved AL blocks 402/408 and 427. Worked well for me for a-1200long while, but not for a lot of others that I know of. So its hit and miss. ANYONE telling you 11-1200 rwhp cars on stock blocks are unicorns. I've herd it all seen it all and its all BS. I'm just telling you the truth. Can it be done sure. Is is smart if you want to enjoy your car any? NO! I do love the Dart AL SHP blocks but pricey, but if you want reliability its my first choice. Now if your going to harp on budget then you can do all the stock AL blocks you want and lets compare your reliably. But hell what do I know only been doing this **** for ever and I beat on my car regularly so if you don't beat on it much then you might skate by on a stock small CI blocks. GL just my .02 of TRUTH.
Same cars cruised for thousands of street miles. The real truth is, it all breaks. I've seen DART, RHS, LSX blocks give up smoke just as easily as a stock one, spending more doesn't make you immune to detonation and other issues. I've seen a brand new pair of Frankenstein heads give up smoke on the first pass, racing will find the weak point in anything. To me its simple, determine your budget and have fun at that level because having to worry about breaking stuff because you spent too much sucks.
Melting Slicks
Joined: Nov 2003
Posts: 2,155
Likes: 269
I'm no expert but would go iron. I understand aluminum flexes something like 3x as much which puts huge stress on everything else. The irons blocks were way overengineered to go 100's of thousands of miles in commercial vehicles which are beat on every day - they are tough.
Drifting
Joined: Dec 2003
Posts: 1,755
Likes: 88
From: Pearland Texas
Is that engine dyno? If so matches up with the relatively realistic limit of 1400-1500whp from a stock block that a few have reached running deep in the 7's. I agree stock block has easily held 30+PSI from a GTX55 94mm.
I tune multiple cars running in the 8's for years with stock blocks, unicorns in the wild Same cars cruised for thousands of street miles.
The real truth is, it all breaks. I've seen DART, RHS, LSX blocks give up smoke just as easily as a stock one, spending more doesn't make you immune to detonation and other issues. I've seen a brand new pair of Frankenstein heads give up smoke on the first pass, racing will find the weak point in anything. To me its simple, determine your budget and have fun at that level because having to worry about breaking stuff because you spent too much sucks.
I tune multiple cars running in the 8's for years with stock blocks, unicorns in the wild
Same cars cruised for thousands of street miles.The real truth is, it all breaks. I've seen DART, RHS, LSX blocks give up smoke just as easily as a stock one, spending more doesn't make you immune to detonation and other issues. I've seen a brand new pair of Frankenstein heads give up smoke on the first pass, racing will find the weak point in anything. To me its simple, determine your budget and have fun at that level because having to worry about breaking stuff because you spent too much sucks.
Melting Slicks
Joined: Nov 2003
Posts: 2,155
Likes: 269
Well just like you I've built a lot of cars and the over all fact is that there are WAY more that break than live at those levels for any length of time. I call them unicorns cause for every one you find that lives, I can find 20 that didn't lol. And like I said I've made huge power on 4 bolts but I won't ever recommend it for someone else. Especially if they are paying a shop or someone else to do the work. If they are a DIY then they know who's doing the work. Same as I have done for years. So I never said it can't be done but its just not common for them to live long and prosper like spock said lol! GL with what every yall do guys.
Le Mans Master
Joined: Apr 2011
Posts: 7,821
Likes: 412
From: Montreal
St. Jude Donor '13
My properly built engine using an LS2 block is still running perfect after 7 seasons. A few at 780 rwhp and 14 lbs boost, and about 5 summers at 1000 rwhp and almost 20 lbs boost. When properly tuned and maintained they can last very well.