I am in the middle of a high horse power Boosted LT1 build and I am going to need a clutch than support 800+ HP.... what are people running for clutches that are making similar power. I would like to avoid converting to a push style Throwout bearing so from what I've seen triple disks are off the table. I see the Spec Stage 5 PN SC425Y looks promising and still appears to be a pull style clutch. https://www.lmperformance.com/702582/sc425y-spec-clutch-stage-5-chevy-corvette-57l-lt-1-lt-4.html. Just curious what everyone is running.

 

McLeod Original Street Twin

https://www.mcleodracing.com/origina...-1994-base/p30

 

How much power are you pushing through this and how many miles do u have on it

 

I have no results yet as it is on a fresh build.
Here is a little more info I asked back ago:
https://www.corvetteforum.com/forums...is-needed.html

 

Is this going to be mostly a street-driven car? If you're ever going to drive it on the street, that SPEC clutch will be awful. It's going to basically be an on/off switch. I keep forgetting McLeod makes that Street Twin in a pull-style stock setup for the ZF6. For a street car, I'd try that with the organic disks before messing with full metallic race clutches.

Also, I don't mean this to be insulting, but...do you really know that you're going to have 800hp or more? I think most people have no idea how much power that really is, or what it takes to achieve that, even with a blower. My C4 had around 410-420rwhp, and most people who rode in it thought it had way more power than it really did. And btw, that car did okay with a fully stock clutch and organic disk, and more than okay with a SPEC Stage 2 (kevlar) or Centerforce Dual Friction disk. What's your displacement, heads, cam? That will tell us a lot about what you're really going to end up with. If you're really building a true 800hp LT1, it isn't going to be streetable anyway. Based on your other thread, it seems like you want this to be a street car; and if it is, then you aren't going to be close to 800hp. The good news is that even if you "only" get an honest 500hp, the car is going to be fast as hell. I think you might want to build the motor and see what you actually get before you try to spec a clutch for it.

 

My engine builder has a forced induction engine package LT1 383 9.5:1 compression ratio with stock ported heads that put a little over 700hp on an engine dyno with 14lbs of boost on a procharger. Now I had a set of upgraded AFR 210 heads (with pistons to keep the compression ratio around 9.5:1) thrown onto this package with a port matched intake and I have a remote mounted turbo which can and will supply over 15lbs of boost. Yes I think this motor should be able to put around 800 rwhp with the wick turned up... will it always run like that... NO but I don't want the clutch to be the limiting factor. The car will be primarily used for street applications however I do want to race it either drag or auto cross and I need a clutch that can hold up. My relatively stock modified setup put down 426rwhp at 10lbs of boost and the upgraded (Carolina Stage 3 clutch) was holding it well I just don't want to chance it with the new setup.

 

So first thing first: I don't know what "relatively stock modified setup" is, but adding 50% more boost to that isn't going to double the power. A significant chunk of that extra boost will actually be from extra heat rather than increase air mass going into the engine. That engine package your builder put together could make that much power with a pretty radical cam, but it won't be a very streetable engine. I've been around builds like that and the only time you'd ever want to drive them on the street is if you're racing for pink slips. An honest 800rwhp SBC for street use is exceedingly rare.

Second, that setup will be terrible for autocross or road course work. So forget about that right off the bat. You'll have such unpredictable power delivery that you'll be slower than a stock C4. It might work okay for drag racing, but with the lag you're going to have I'd strongly suggest a heavily built automatic with a loose torque converter instead of a manual. So again, I'd strongly suggest you really consider whether this is the engine build you want for your stated uses.

Third, I think the only clutch that will hold 800rwhp and have any hope of being streetable is the McLeod Street Twin with organic disks. I think you should actually go drive some cars with full-metallic single-disk clutches rated for that kind of power so you can see what I mean when I say they will be awful on the street and function like on/off switches. I also think you should drive some cars that have similar heads to yours and make an honest 800rwhp and see if that really suits your desired goals for the car.

 

By relatively stock motor I mean a bone stock unopened 94 LT1 with Exotic Muscle Long Tube headers and a remote mountedmounted with 10lbs of boost put down 426rwhp 467rw ft/Lbs of torque on a VERY conservative safe tune. So given my experience with my last build I don't see why a fully forged built bigger displacement motor shouldn't be able to at least give me the 700-800 horsepower that the builder says it should make.

I started this thread to find out what people run for clutches on their higher horsepower builds so I can figure out what clutches work and what dont not to get in pissing match about what I am building with people that don't know what is being built. I never said I was building a 800rwhp motor just a 800hp motor. My engine builder says the package I selected dynos on an engine dyno at a shade over 700hp with 14lbs of boost without the additional upgrades I am having opted to have done (bigger heads for better flow and portmatched and polished intake manifold) . I tend to believe him seeing as he is a very reputable LT1 builder and he has been in numerous publications, in fact the engine package that I am buying was originally done for a major car mag.

 

You will be somewhere between 650 to 700 rwhp. Looking forward to see your to final build; sounds like you're doing all the right things to get you there. Go for the Mcleod Street Twin.

 

Hey Impala,
I'm from Bolton MA. Cool to see your from Auburn. Is your 13.6 with the combo you have now? The LT1 with 10 lbs?

 

Is the rear-mount turbo setup ready to go? I saw your thread from 2014, beautiful car and the turbo install looks great
https://www.corvetteforum.com/forums...post1587137705

 

I'm not saying it's impossible to build a 383 LT1 with a lot of boost and 800hp (crank or rwhp). I'm just saying that an engine like that isn't going to be a street engine. It just isn't. And it's also going to be a terrible autocross engine with that rear-mounted turbo.

This isn't a pissing match, and it's very relevant to your question about clutches. It's relevant because one of two things is going to happen:

1. The engine is going to be mild enough to be a good street driver and make a lot closer to 500-550rwhp (maybe 600-650 crank hp). If so, then asking for clutches that will hold an honest 800hp is going to get you recommendations for clutches that will ruin the streetability of the car. That would be unfortunate.
2. The engine is really going to make 800hp, you'll need to run real drag slicks to hold that power, and the clutch will need to hold that kind of power during drag racings shifts. If that's the case, then the engine will be awful for street or autocross use and you need to find a good drag racing clutch, because street manners won't matter anyway. But you're going to be going through driveline parts and you should seriously consider just switching to an automatic that's built for this purpose.

IOW, I don't think your stated intended use matches the engine you said you're assembling, and that makes it impossible to recommend a proper clutch.


Surely that's from the car when it was a dead-stock LT1 with no boost, and he just hasn't updated his signature in years? I see you working, Tom.

 

the 13.6 @104 was when the car was completely stock down to the paper airfilter and just a set of Mickey Thompson ET streets to help me launch. I did that at Epping. I never got a chance to drag race it when I had the turbo on it.

 

thanks for the compliments... I can't wait to get it back together again I miss driving this car.

 

the intended use for the car is primarily a high horse power street car that will see some drag use and auto cross action. Neither drag or autocrossing I am super competitive in I just do them because it's fun. The car was fun on the autocross course when it was turbo, real predictable and had great midrange I am hoping having a built setup may expand on that experience.

 

EPPING!!!! I LOVE IT!!

My god, I miss that place so much! I had so many good nights at that place, back in the day. It was modest, comfortable feeling, and I always got a lot of passes in there, pretty easily. Epping.....

Copy that on your runs. Nice times. I did figure it was box stock, but you never know.

 

Where are they holding auto-x's around there these days? Back when I lived there, they did some IN Auburn, right there by 290 and the Mass Pike....there was a kind of industrial facility there that we had events in some times.

 

I was going to Fort Deven in Ayer for SCCA autocross events as well as Bay State Corvette Club events. But I haven't been there in close to 5 years so I don't know if it's shut down.

 

That's right. I forgot about Ft Devens. Yep, that was a place too.