questions about the integrity of an LT1 block

[1slow94z28]

Not sure if this is the sub forum to post in, mods please move if so.

So my question is, had anyone built an LT1 that held high horsepower, with reliability as if to compete in say the tx2k events or Texas invitational?

[Blackbird96WS6]

I think 8SEC6SPD would be a good one to talk to here.

[popo8]

BIG CAT

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[popo8]

Tony Shepherd

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[popo8]

soooo many more.

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[popo8]

what do u consider HIGH ho...

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[Blackbird96WS6]

If he's talking about going to TX2K events, I'm guessing he's talking about a 900-1000 RWHP minimum to compete. Most of the cars there are 1000+.

[Chopstix]

BigRick 1200+ and Stefan both pushed more than that out of a LT1 block

easy to do ...no....if you are wanting to build a tx2K car you might want to consider a different platform....1kHp are the little fish in the pond

[Ryan Stout]

Iirc UGR had an 1800hp car this year.

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[Blackbird96WS6]

Iirc UGR had an 1800hp car this year.

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Yeah, kinda hard for any LT1 to even come close to competing with something like that.

Just another all show no go bird

[Injuneer]

15 years ago George Baxter had an 1,125 flywheel HP LT1, blown 383, built by Second Street Speed. Before they built the engine, they evaluated the block. They felt the LT1 block had many of the features of the Bowtie performance block. The webs were designed with the meat required to support the straight 4-bolt mains used in the Corvette LT1's. They did NOT fill the block. Even kept the Opti, using the optical cam position sensor to feed a MoTeC ECU.

At what I recall was a 3,800# race weight (30th Anniversary convertible, and George wasn't small). First pass off the trailer it ran 9.05 @ 156MPH. I have a video of the pass. When he rolled up to the line for the second pass, the blower sounded "off" and he shut it down, and we pushed it off the track. Blower rotor had started shedding blades. I have no doubt that would have been the first LT1 into the 8's.... but "woulda, shoulda, coulda", if you ain't got the timeslip it doesn't matter.

Then he went off the deep end and had them build a new 383 on a Dart Iron Eagle Gen 1 SBC, and made 1,350 flywheel, running low 8's at close to 170 MPH. One of the other members here got George's LT1 block, still judged to be in excellent condition. He started building a high HP nitrous motor, but it never quite got finished.

[Neil350]

Really depends on your goal, you could go out and have fun if you were making around 1000rwhp because there are a couple cars at that power level, but realistically you would get stomped hard by the nastier cars there. I help out with a couple cars that run T.I, two f-bodies and a silver Supra, to have a strong mid pack car, you would need to be around 1300-1500 rwhp in a F-body due to weight. I think the min weight at T.I is 3200lbs. So you still wouldn't win the event but you wouldn't get stomped by everything. To be competitive enough to possibly win, 1900rwhp+. None of the LS1 cars that I help on have factory blocks both are LSX blocks, ones a 4L80E and the other is a TH400. They're also strict on the cars, factory glass and full factory interiors. The slow cars at T.I trap 150s in the 1/4. Which an LT1 is capable of, Jose at Forced Inductions built an 88mm 355 Formula with a six speed that trapped 15x MPH. But you have to keep in mind guys like Mike Colby with an AMS GTR traps damn near 180MPH in full street trim.

Some one did bring a nice LT1 Z28 with a blower, it had issues all weekend. There's a couple fox bodies, a white LX that runs 210MPH in the TX Mile and a convertible fox that's around 800rwhp. Neither make it to King of the Streets or six speed challenge but they still have fun running them. Recently they started an under 1000RWHP event at Cado Mills, I think a turbo LT1 could do well at that because the power goal isn't out of reality. Just not at Texas Invitational, there you have to race against the best of whats out there with unlimited budgets with large support teams. It's like trying to build an LT1 to win Out Law Radial, the block is really impressive for what it is, but you're asking a bit much of it to want to be competitive at that kind of event.

[1slow94z28]

Thank you so much for all the information guys! I know the lt1 block is strong, and I now have a perspective on where it's limitations lie. .

[1slow94z28]

I wrote a reply and it isn't showing

[HellTeeOne]

The LT1 block can support comfortably over 1000 streetable rwhp, but the turbo Vipers, Lamborghinis, Supras, GTRs, and LSx cars at events like that have already been in the 1500-1900 rwhp range for a few years now. So no, a LTx car that is anything resembling a street car won't be competitive in the upper echelon of those events.

1000 rwhp is strictly mid-pack. If you're bringing less than 800 to the party you're going to get walked by nearly everyone there.

[1slow94z28]

Thanks guys for all the input! I know they hold some decent power but the block definitely has its limitations and we'd benefit from a aftermarket one which we'll probably never see

[popo8]

I wrote a reply and it isn't showing

approved

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[FlatBlackZ28]

I can't post!

[FlatBlackZ28]

Now I can. Just wait for the big bore block. It will open up new avenues for heads, intakes, headers etc etc. Plus the benefit with the current heads we have. 2000 hp here we come!

[Fastbird]

Good luck with that. There's never been enough interest for a company to warrant the initial cost for a production run of large displacement LTX blocks. Nor will there ever be with the very small enthusiast group for these motors coupled with the absolutely thriving Gen III+ motor market.

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[popo8]

Now I can. Just wait for the big bore block. It will open up new avenues for heads, intakes, headers etc etc. Plus the benefit with the current heads we have. 2000 hp here we come!

Love ur POSITIVE outlook. :)

LTXtech.com is my DRUG!

[94Blackbird]

Now I can. Just wait for the big bore block. It will open up new avenues for heads, intakes, headers etc etc. Plus the benefit with the current heads we have. 2000 hp here we come!

Never gonna happen. It was talked about years ago, but got shit canned because there isn't enough interest.

[1slow94z28]

I'd be in line the date of release with cash, credit, saved change etc if they ever put out a block lol

[Neil350]

It would be nice, Bill Mitchel pushed a lot of 409 stuff through WORLD products because he liked that engine. The LT1 stuff would be kind of a weird duck, because if you did get that block most the heads you would want to use would then have to be converted to reverse flow. Which leaves the question of if you wanted to build a 2000HP+ SBC why not just start from the tons of after market SBC blocks already out there and use what ever heads you want? Just be easier. I guess people want what they can't have, but the LT1 is far from a bad block it's proven to be pretty damn strong. The LT1 power limit is actually pretty close to the 2JZ, they have to concrete those blocks when they start trying to make big power, 1400+. But they've always had a ton of money to keep pushing those motors to new limits.

[Tony Shepherd]

Lots of good advice and info in this thread. A couple of things I will add when talking about the limits of a LT1 block, years ago I noticed very high rpms causes main caps to walk a little even on properly done 4-bolt splayed blocks. When I say high rpm I am talking 8,400+ RPM's. I then lowered the duration on my cam so my powerband tops at 7,600 to keep from spinning so high. I was making more power higher up but I knew it would not live long. You also have to watch the trueness of the cylinders after a period of time and passes. They do move around. My biggest complaint about the stock block is the small bore. Other than that, I have yet to have a block fail on me.