blackdak318

Also - if you have a big power LS3 build...post up the details, how much power it makes, and how fast it has been. I trust that more than people making inferences on how strong certain parts are.

Maybe more importantly than that, post up your big power LS3 build that failed, and what caused it!

Bluewheelz

Looks like you have a good plan. Like I said, keep us updated. I see a lot of post threads that don't update everyone on how it worked out. Just keep the boost at a reasonable level.

blackdak318

Will do. Got the mains off last night and they aren't that bad. One is a good streak in it down to the copper and the other show some signs of wear, but not terrible. The biggest things is the thrust bearing isn't destroyed. I"m 99.9% sure my block is fine, same with rods and pistons. This motor could have new bearings thrown in it and put back together, but I was already thinking of putting a forged crank and ARP mains in it so I'm still sending it to Mike Lough Race Engines. I believe one of the mains did show sings of the crank starting to flex so it will be nice to get that taken care of so I can throw another 100 rwhp at it.

nareg

I had a LS3 with diamond pistons callies rods stock crank, ported factory heads with a D1 and nitrous on e85. made 950 and held up great. Then I put a F1X on the car it made 1100hp on e85 and it would lift the heads. The D1 and nitrous setup was on my car for a year. I'm sure if I kept the D1 and nitrous setup it would still be running like a champ today. I never took the car with that setup to the track although I wish I did. I did however take it to a runway rivalry event in Dallas and from a 60mph start my best trap speed was 167mph for what its worth.

Now I'm almost done with my new setup for the F1X. LSX 388 air 2 water setup etc.

blackdak318

Thanks! Appreciate the info. Sounds like I should be pretty safe at 950-1000 rwhp which is all I'm shooting for. I will probably eventually pick up a set of 3/4" thick deck heads as well.

Turbo-Geist

If you are worried about trashing $4,000 worth of parts, I would stay below 1000 flywheel horsepower. Things can go south very quickly and you will end up spending the money again or abandoning the build. You've heard from people in this thread that had solid setups with $ invested and things still happened. There are so many other instances out there which are never posted. Pushing it with stock parts has been the most fun and least cost in my experience.

jayyyw

TSP sells Darton sleeved, 5.3 aluminum blocks for $2600. If that's an option for you.

blackdak318

Turbo Geist - I understand fully what I'm getting into and the risks I'm taking. That is why I've been struggling with the many options and decisions I now have in front of me. I have realized I don't realistically need 1000 rwhp though and even though 5.50's are my 1/8th mile personal goal, I would be perfectly fine only running 5.60's and having an extra 4k in my pocket. Biggest thing I realized is the extra money required for a dart 6 bolt motor could be better utilized at other areas of the car. Currently it only has a 6 point cage that I want to update to 8.50 cert. I'd much rather be safe than make 1000 rwhp. The car also still has strange single adjustable shocks on all 4 corners. Id be better to get some nice double adjustable than make more power if it won't hook. I'm confident the new set up would be safe to 950 rwhp and that is close enough for me. That should be good to my 5.50 goal as well. This is all currently in a 3080# fox mustang, not a corvette.

jayyyw - I saw that a while ago and looked into it but it's more expensive than a dart block (they're about $2,300) and you're still stuck with only 4 head bolts and factory LS oiling limitations. I'd just pull the trigger on dart or an Iron 5.3 before going that route.

lt1z

I'd say 850-900whp is max on an LS3 block for any length of time.

blackdak318

I both agree and disagree with that. If you're talking about not worrying about the block at all for 10+ years. Agree 100% that is a safe and conservative number. For what I'm doing I'm ok taking a little risk here and there and pushing it a handful of times a year. My motor has 2-3 years at 850 rwhp thru an unlocked 4L80 which is really more like 900 thru an M6. That is also on the stock crank and main bolts. When torn down it had zero signs of issues block wise. No signs of lifting heads, cylinders are still nicely cross hatched, etc. I personally think it would be fine at 950 maybe even 1000. Keep in mind this is with E85 and conservative timing that puts a mark right at the bend of the plug strap.

Woodstoc

I got over 50K on a Heartbeat (570HP to the RW), with a LOT of spirited driving and racing with stock rear and trans. Still going strong. Not nearly as high as a lot of guys on here, but I prob have more miles than most.

Detoxx03

Corvettepower11

What kind of sign would you get that you are lifting the head before major damage occurs. I'm about to install ysi on a forged 416 ls3 with stock block arp head studs Holley hi rise. Was hoping to get over 1000 rwhp with the 2.75 upper and 10% od lower but after reading all the comments got me nervous.

Corvettepower11

Made 850 with a Paxton 1500 on stock rotating assembling just changed cam and valve train components

lt1z

I would call 850 the max safe level even though people have gotten away with more.

blackdak318

The only way I know of is to install a pressure sensor in the cooling system and log it. Anything over 0 pressure and you know it is starting to lift the head as pressurizing the cooling system with boost is the first thing that will happen. If you have a stand alone you could also create a safety to pull timing if it starts to see that.

blackdak318

Also my own personal update - I've decided to sell my current LS3 and go the 6 bolt route. I just never felt comfortable with a LS3 block given what I want to do and after I sell my short block, I won't have much more into a Dart LS Next SHP set up.

This is the new plan:
Dart LS Next SHP - 388"
Molnar Forged 3.622 Crank
Molnar Power Adder Rods - Their proprietary ARP 2000 rod bolts
Diamond Race Series 4.125 bore piston. Total seal AP steel rings. H13 pin

Here is my current conundrum though. I don't have the budget to upgrade my turbo at the same time as this (Comp CT5x billet 82/100). The turbine on this turbo is terrible and I don't beleive it will allow me to make any more than 850-900 RWHP. In order to spread the cost out I was planning on installing my current GMPP CNC LS3 heads on this short block because I'm confident they will be fine with whatever this current turbo will put out. Then in 1-2 years I would upgrade the turbo and I was planning on putting a set of AFR LS3 6 bolt heads on this short block. I don't believe I can do that though because the GM heads are 15 degree and the AFR heads are 12.

I could just install a Dart/Brodix as cast or CNC 15 degree head when I decide to swap them but I believe the AFR LS3 to be a superior head, especially with the 260 port size vs. the 280 port size of the brodix and dart.

Thoughts?

stevieturbo

You do realise that it is perfectly normal and necessary for there to be pressure in the cooling system ?...hence why it is a sealed system with a pressure rated cap

So if you had zero pressure....you've burst a hose !

With the system intact, you need to find what is the normal operating pressure range for your vehicle and then after that you may be able to use pressure in the system to determine if there is a potential problem.

blackdak318

Yes sorry worded incorrectly. Normal pressure then anything above that.

truggiero19

If you are going to run a 4.125 Bore why not run an LS7 style head? Or are you committed to the intake manifold you have?

I understand staying with the LS3 but just making sure you realized that it might be a good time to switch.

I plan to also run a 388 next. I have a spare LS3 block my roommate is hooking me up with sleeves for. I'm going to run the factory forged dry sump LS3 crank with Molnar PA rods and upgraded 4.125 wiseco pistons. I already have Greg Good ported LS3 heads thus I will be keeping them so I understand why you would as well.