Builder

There is a company called American Speed that makes N/A carb and distributor SBC engines with 10.x compression and up to 720 BHP...and they use old blocks so they don't have to be smogged.

Check their website:

http://www.amerspeed.com/cgi-bin/showultimaengines.cgi

So, what am I missing here? Are these engines just not streetable? Yes, they are too expensive and I would probably never buy one. But, is this setup really a good way to go? Why would a guy get all tangled up in an OBD-II, FI, and multiple coils when a carb setup (like those below) can produce so much torque and HP? I really like the LSx. I have an LT1 in my Impala SS now. But, I have also seen the Edlebrock carb intake manifold for LSx, which makes more power than stock.

377 c.i. 700 hp @6600 rpm 18 deg. Dry Sump 565 ft. lbs. torque @5000rpm $25,695

406 c.i. 720 hp @6400 rpm 18 deg. Dry Sump 580 ft. lbs. torque @4800 rpm $25,995

Thanks, all. I am guessing the main reason is that street manners across the entire RPM range is better with FI. Your comments are greatly appreciated.

CSiJason

For 25 grand I bet you could make more power and torque streetable from an LS-anything on boost, plus it would be more friendly when it comes to changing weather conditions and such. Electronics are only scary to those who dont understand what they do and their advantages. Now i'm not saying you couldnt build a hairy SBC on carbs but it is going to need every bit of attention you can give it. Give me a blower or turbos any day over N/A.

Builder

I hear'ya. I am a computer geek, so it makes good sense to me that a computer-controlled ignition and injection would be capable of more power and be more dependable and managable. Obviously, the General thinks it's the right way to go (along with every other manufacturer). So, where does all of that carb-engine horsepower come from?

CSiJason

Compression? Displacement? Big cams? Combination of those? I bet if you put that much effort into building an N/A big displacement engine with electronics out of an LSwhatever it would be capable of making similar performance numbers too.

technical

When you get into the high end HP heat becomes a significant factor. Not to mention gas mileage ~2mpg. They're very fickle as well. You won't always be able to head out to work in the morning and have it run right without screwing with it. SFI constantly adjusts for varying climate and other factors. Remember carbs need to be adjusted routinely. eg. Car runs great at 80* but won't idle at 40*. Could they be streetable? yes Daily driver? no.

CSiJason

Basicly my thoughts exactly.

Builder

Okay, that makes good sense. Where I live the temp can range 40-50 degrees on any given summer day...95 to 105 daytime, 50's at night. Sounds like a highly tuned carb setup could/would be a major pain. Thanks for pointing me in the right direction.

I won't be spending $25k on the engine...but prolly $12k. Was originally thinking Scoggins short block 402 LS2 with lower C/R for a turbo. After reading Jerami's FAQ, and other info, maybe an LS1 build-up would be just as productive and reliable and maybe less expensive. Can a stock LS1 block be used to make a reliable 402? Reliable to me means not exploding every 25k miles. Or, is that just crazy-talk?

Thanks, I really appreciate your input.

technical

A low CR LS1 stroker kit + cam (reasonable lift) + turbo could be built to be very reliable at reasonable boost levels. Any engine can be almost bullet proof if they are built right.

Builder

That's good news. With all of the fantastic numbers on this board, it makes me wonder how long the engines last. If GM builds the SBC to a 50 percent duty cycle, I imagine pushing them to levels above that shortens their life...thus, the huge aftermarket for stronger engine blocks and internals.

That said, I have started a spreadsheet with a general map of the goals in mind. I will attach it on the next post with hope it will be examined, picked appart, and reshaped into a real, buildable list.

Please stop me here if this too far off topic, as I am sort of new at this.

Thanks again for your comments...

Builder

Spreadsheet attached. I hope I have overestimated pricing. Please let me know your thoughts.

The file (408-SBC-01.zip) is an Excel spreadsheet.

-- Scott

technical

Just to clarify... SBC != LS1. Some might get confused at what you're looking to do.

Builder

Yes, thank you. Edited the file above to change the name and with most recent info.

technical

At first glance, your goals of a daily driver and some of the items you're looking to buy/install are not quite in sync.

3 stage dry sump? wee bit overkill for a daily driver.
If you have to buy everything outright, you might also look at MSD's ignition coils. I believe they cost about the same as what you listed for GM's.

Chromoly pushrods will do just fine. Don't know if I've seen Ti push rods.
Threaded freeze plugs are probably ok for NV, but I'm not sure they're necesary.

I'd get ARP studs for the heads/mains.
You might also decided on the FI before you decided on the heads. Also the cam.

You mentioned smog...do you have strict smog in NV?

Builder

Figured...haven't done this before. Just pulling together the threads and concepts I have been reading about for the last couple of months. This spreadsheet was only started yesterday. I don't know if this spreadsheet approach is a proper method. There's got to be a standardized form out there somewhere for this process, no?

Yes, that was skipped in my configuration. Didn't put a "1" in the quantity field. Thought it might be an option, but definitely overkill.

Good option. I have to read more about the FAST system. I think it can use any mfg coil. May as well use MSD.

The TI pushrods were my invention...don't know if they exist. I figured a pushrod has to be one of the biggest masses moving in the valve train, so make it as light as possible. The threaded freeze plugs are something I read about in an engine rebuild book. Sounded like a good idea, but am not sure of the pros/cons.

ARP all the way around. For sure. I can't believe the difference in quality of those fasteners. Almost certain that the FAST sequential system is the way to go for FI.

The SMOG issue is not so much a NV deal as it is for this county. Here in Reno, we are on the CA border and also very close to Lake Tahoe. There are only two counties in NV that require an emission test; this one (Washoe), and Clark (Las Vegas). However, I plan on building this car and also having a small property out in the next county over...where it will be licensed.

Can you see where have I left anything critical out? Are there gross errors in compatibility that jump out at you? Can you relate any stories as to the strength or weakness of any of these components? Starting at a CR of 10.4 do you think these components can handle a 200 hp shot of nitrous without cracking?

Thanks for your time and comments.

technical

Threaded freeze plugs are just that...threaded vs. press in. Since you live in a relatively temperate area, that probably will be fine.

If you had to pass smog, then you'd have to be very conservative.
You'll find that most of the aftermarket LS1 parts are pretty strong. As for a 200 shot, I'd post that question in the nitrous section to see what those guys think. A forged bottom end should be able to handle that at 10.4:1, but I couldn't say what gas you'd have to run.

As for forced induction vs n2o, I'd figure that one out before you start. That decision will determine the type of heads, cam and maybe a few other things as well.

Hopefully some of the big HP guys will chime in here also. I only make a measly 400rwhp.

technical

90 lb injectors? I think not.
$800 for ls6 heads; unported. They'll be more like +$2000 for assembled P&P.
You also probably don't want solid roller for a daily driver. I'm sure there are people who do it, but I wouldn't want to be bothered.

I've heard ill things about some of the Clevite bearings. Consider some alternatives just in case. Federal Mogul?

Builder

Okay, so that's a coin-flip. If too expensive...pass.

Thanks, I will do that.

With this first go, N2O will be the choice. A turbo will complicate the exhaust system beyond what I am prepared for, as the engine compartment doesn't have much spare room.

Measly? Maybe compared to some, but not exactly.

Injectors were changed to 75#. Probably don't need 90. May not need 75#. Figured the heads and valve parts separately. $2k is not out of line for the complete assy.

Oh, that's not good. Thanks for the heads-up.

I appreciate your comments...

technical

Definitely make up your mind about the N20 vs. turbo/blower. It'll make a big difference when picking heads/pistons and such. You might want to build a 9:1 motor for a turbo, but if you decide later on to go N20 then you'll be way down on HP without the juice.

Builder

Okay, posted on the Nitrous board. Generally speaking, it's not recommended for road course use. And, some sanctioning bodies don't allow it. So, here's the bottom line. I am going to build a N/A engine.

Need to use pump gas, so probably no more than 10.6:1 CR if that is acceptable with 91 octane (what we have in NV and CA, which is where I will be driving most of the time). Then, if I decide to go with boost, I can change the heads or internals to adjust the base CR down as needed. Build it solid, and I can spray for the strip if I want, but won't do so for the road courses.

Now, with the above framework, what would be the most torque and horsepower I can make? To this point in time, I have lived by the saying that there's no replacement for displacement. That said, what I have read indicates that an aluminum block can only be bored out to about 4.160" due to the sleves. I have not found the max stroke yet. Stock stroke would make something like 388ci with a 4.155" bore. Looks like the iron block can deliver 408ci.

Would you say I am on the right path?

Thanks,

technical

Well, you're going to spend quite a bit on internals that you won't want to change later just to get the compression down a bit to run a turbo/blower.

You're going to have a hard time building a motor or car that performs great on the strip and auto-X and still be a daily driver. You'll have to settle for something. I'd go the auto-X route since the main differentiating components from road car to street car are suspension and tires which do not affect gas mileage and emmissions too much. This way you can build a neck bender that goes fast, but remains very streetable. eg. Adjustable coil overs. Don't try to build the biggest monster of an engine that will kill you on a road course or auto-X.

As for the engine itself, the sleeves are the bore and they're only good for ~.010 hogging. Otherwise the block has to be resleeved for larger bores (sleeves). The largest LS1 I think is ~430-440ci.

You need to focus on the car a bit as well. Strengthen the chassis and rearend.