When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Experienced builders help me decide which way to go with new engine.
My setup as of now consists of a LS3 longblock with ARP rod bolts and head studs. Car is a C5 Z06 with custom S480 turbo setup and a powerglide conversion. It weighs 3200lbs and has ran a best of 5.5@129 on E85 with pretty loose converter up top. I've reached the limit of my comfort zone with the SBE and want to upgrade.
Goal is 140+ mph 1/8 traps and 175+ 1/4
With that said from a longevity standpoint would you guys recommend doing a 6.0 iron setup (would love to keep aluminum LS3 block but worried about strength) or a 5.3 setup. Will keeping the heads down be easier on the smaller bore setup? Callies dragonslayer, Ultra billet rods and wiseco pistons will be used either way.
If I go with the 6.0 block I can reuse my intake manifold and even my heads until I get some aftermarket heads.
If I go 5.3 I will be starting from scratch. I like the idea of the smaller cubes for turbo sizing and backpressure concerns if I decide do any class racing.
I would like for it to be capable of putting down a reliable 1200whp (turbo upgrade will come shortly).
I don't really have the funds for a 6 bolt/LSX setup at the moment but would love to go that route at some point.
Surely an alloy 5.3 with 625's or 1/2 studs will hold pretty much anything you can throw at it and tune well ?
If you want to really push it, just dont go nuts with a crazy high CR. More boost/lower CR is far more friendly with cylinder pressures than more CR/timing for same power levels.
The blocks are the weak points at the power levels you'll need. It makes zero sense to use another OEM block. They will be no more "reliable" than what you currently have. You could half fill the block you have, convert to methanol. You're current long block will be as reliable as any that way. With the right turbos you can meet your goals on the current long block. But I don't think the word reliable should be used to describe any OEM block at 1200whp.
Keeping the heads down on an OEM block at those levels is another big issue.
Used aftermarket blocks are another option.
This is the fastest stock block/head car I've ever seen. Beryllium head gaskets are the way to go with OEM blocks apparently. He is making well over 1200hp with standard ARP studs on factory block/heads.
I read that thread a couple weeks ago. Very impressive setup they have.
Yea the more I think about it the more I feel I should just go to a LSX block and even if I have to run my heads for another season so be it. I can upgrade to some 6 bolts heads later on and then really lean on it. I want to keep the car on E85 and probably go to a billet S484 to run in the street car classes we have local. I really wanted to run World Cup Finals next year as well but my class is limited to a 76mm turbo and I can't afford both turbos lol
I would do an aftermarket block for sure. You will never have to worry about lifting heads at 1200 whp, you will only have to do it once, and the only difference in price is the block itself.
You can put the heads you have now on and run it for a little while until you have funds for 6 bolt heads later on. The cost of making 1200 whp vs making 1400-1600 whp is the same as far as the bottom end is concerned.
I am really considering buying the LSX376 B15 crate engine. Pulling the rotating assembly out, selling it and putting in my own LOL. Sounds crazy but that longblock is priced very well IMO. Hell if I knew the LSA crank and the forged pistons in the B15 were strong enough I'd just throw some ultra billet rods in it and call it a day. Along with valvetrain and ARP fasteners of course!
I would definitely put head studs in it and possibly main studs as well. Only part in the bottom end that has me concerned are the rods. Same rod that's in my LS3 now. I need a 24t reluctor as well so instead of running the LPE adapter I'd assume just build it with very good parts
Is it still same value if you need to buy it, strip it and change half the parts though ?
Does it use 11mm studs or like the LSA or whatever the 12mm studs ?
Not real sure about the stud sizes but even just buying a built LSX short block is usually well over $8k, then another 2500+ for 6 bolt heads. Then valve train, valve covers and all the other covers gaskets and what not. I can get that b15 for 7600 with all covers and complete heads. Sell rotating assembly for 800-1k ish and spend another 4k tops on good internals. Even if it's within a few hundred dollars of doing it all separate it just seems way more simple to me this way.
I haven't decided yet either way but hell guess I could even run it for a season the way it comes just not lean on it to hard until I replace internals.
If it were mine, I would go for one of the new Dart LS Next aluminum blocks with the new full skirt design that they debut at PRI. It is just superior to any other block in my opinion.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
Experienced builders help me decide which way to go with new engine. 
