Strongest is a relative term. Strongest per dollar? Most power capable? The current strongest I have seen is the Noonan billet. Some guys are pushing way North of 2000hp through them in grudge cars. The strongest cast block is the Dart Alum by far. Also 2000hp capable. The best bang for the buck is Steve's resleeved 5 3 block. I think there is something to be said for a lightened iron block depending on the application, though.

 

I'd think the the LS9, probably followed by LSA for 4.0xx + bore OEM blocks depending on how far you want to go as mentioned the LC9/L33 are going to be choice for really getting after it with an OEM block.

 

Here you go: https://sdparts.com/i-24507960-sdpcr...are-block.html

 

I don't want an iron block I'm dead set on aluminum.

I've been running my current ls3 block with a procharger for about 5 years now. The first 3 years were with a D1x at 15 psi and toward the end about 17 psi. Then I put the F1a-94 on it with 20 psi for a year and then 22 psi for the last year. Blower is spinning beyond max recommended impeller speed now by a little bit.

I'm on stock crank and stock mains and fasteners. Forged rods/pistons with arp head studs, stock unported cathedral port heads, btr intake, and stock ls1 throttle body with an adapter for the intake. Around 1000 rwhp based upon trap speed/weight. I did all the work and tuning on the street/track no dyno pulls.

I admittedly am not as skilled at engine building as several of the guys on this forum. This just shows how easy it is to make power these days and that around 1000-1200 rwhp is no problem for about any of the oem blocks/cranks. It's at 1200+ that stock block and cranks become a concern. ...of course bad tunes are always a concern even at much lower power levels.

I'm thinking the F1a-94 is the end of the line for me on stock block/crank so I'm considering what block to use going forward with an F1x. This car is already too disadvantaged, so I do not want to add any weight to the front of the car.

 

You nailed it on the tune. I believe it is the single most important thing involved in a high perf build. Hell, even a stocker. With a few boltons and a damn good tune, I had a stock internals 2000 A4 C5 vert running mid 12s@114 mph. Best was 12.50@114. I got a 12.89@110 thru the stock exhaust manifolds, without cats (gutted). Got kicked off the track at Lapeer, Michigan due to no roll bar. Back in 2004, NHRA stipulated any vert running 13.99 or quicker must have a roll bar/cage. IDK if same rule is still on the books, or not....

 

In 2005 I was running 10.2 at 135 mph with no roll bar driving the car 2 hours each way to the track and home with a heavy GTO. I only run 1/8th mile these days but 5's driving to and from the track in a GTO (not the same one that went 10.2 in 2005. I sold that car in 2008ish. Should easily go mid 9's or better in the 1/4 now with the current car.

 

You asked about the LT block, the L8T is the block they are getting big power from that is iron. I’d imagine aluminum versions will fall well short of the 2k that SDPC achieved.

I know you’re setup, and know you want to stay aluminum, so your options will be a LSR flavor block or a heavily modd’d LS9 or LC9 which will ultimately be close to the LSR all said and done. Dart also has an aluminum flavor but I’ve read mixed reviews on strength at bigger power levels which would be disappointing.

 

LME stated that "most" but not all LT aluminum blocks fail at 1500 rwhp. I'm at 1000 rwhp now with an ls3 block and looking to make 1200 rwhp with an F1x. I don't expect to get over 1300 rwhp on ethanol and meth injection so I don't need a 2000 hp capable block, but may end up going that route since no LS blocks with 4 bolt heads are reliable at that power level. Yes it's been done but more have issues above 1200 rwhp than don't. I really want to go with a 388" stock stroke combo the procharger likes a little more cubic inches in a heavy car than a 5.3 and I do street drive it a day or two a week.

 

Was your car a convertible? I know some tracks don't care. Ubly and Milan in Michigan didn't care, and that was when I was near 10 seconds with my Darton motor. Never any trouble at either place. Guess rules enforcement varies from track to track. When they black flagged me at Lapeer, I saw the track owner, and told him I'd run a dragbike there that was faster than my car. I asked which he thought was safer@125mph. He said "You're probably right, but it's my track, and your done!!

 

I've never owned a convertible I don't like them personally. It doesn't matter who owns the track they don't make the safety rules it's the governing body NHRA, IHRA, WDRA, etc. If they find out the owner is allowing unsafe practices breaking their rules there could be repercussions. This happened with a track that had someone ride down the track in the back of a truck a few years ago. I'm low budget I've only ever owned oem stock blocks but I've still managed to run 5.9x in the 1/8th this year which would easily be low 9's in the 1/4 with a heavy GTO. I know that's not that fast but I'm doing this with stock heads, stock throttle body, stock ls3 block, and all work and tuning done by me with the exception of having a buddy come over to my garage when I was ready to drop the motor in to help out.

Point being 1000 rwhp is easy and a lot of guys are over building these engines for less power than this when they don't need to.

 

It's a question of $$$, how much can you spend vs. how much can you can afford. Given your power goals, I would go Dart iron and maybe have it lightened some. Yeah, are you adding weight, sure, but you are also adding reliability, capability, and more power because of better ring seal at the same boost levels. A Dart alum would probably be your best bet considering you want to grow the combo and that's 7k these days. To go next level over where you are at is going to be expensive, it's just a matter of how far you want to go vs what you can afford.

 

Hope you're being sarcastic, lol If you're running in the 5s in the 1/8 mile, you've got a damn quick and fast car in my book. Faster than mine, for sure. I gave up on having the fastest car, bike, whatever, by my mid 30s. No matter how fast you go, there's usually someone who is faster. I'm just trying to have a sleeper C5 that runs much better than it looks. I'd be mighty proud if my car ran low 9s in the 1/4 mile like you have!!! You've done VERY well, indeed! I agree with you on the blower. Yes, I'm N/A, but if I was a young guy again, I'd be saving for a blower. There's a reason the OEMs have abandoned N/A engines with 600+hp (the new 4 valve, 5.5L C8 engine being the outlier). I believe the reason is long term reliability, fuel efficiency, AND power....