Moochdog

What's up to you all? I have a 93 z28 with 180+ miles I want to rebuild the engine myself I plan making this car a weekend car for beating or keeping up with the newer cars mostly mustangs around here. I've researched around to find the the 383 will have more power and torque than the 355 so I'm wanting to know which is best I've looked around for stroker kits and found one for 1600plus the kit includes everything in the cam and all. Since Ima build it is there anything I need to know about the engine I know that I will need an tune but can the 383 be ran without a tune at 1st or not because of the increased stroke.

ACE1252

The displacement of the engine in the tune will need to be increased. You will also need higher flowing fuel injectors....that will also need to be tweaked in the tune.

Other things that will need to be adjusted will be the VE and spark maps. Idle parameters may need to be tweaked as well....

In short, you will need to get a tune before you run it.

96capricemgr

iTrader: (1)

A 355 will need a tune first too, unless you keep stock cam, compression, displacement, injectors.

bufmatmuslepants

iTrader: (3)

I recommend using the Search function on here, go to advanced search and narrow it down to the LT1 section, and find a build thread you like, and copy it.

I also recommend keeping thick skin and taking advice, comments and criticism with an open mind, knowing forum members do not profit from your success, we only like to see the LT1 platform succeed, and we want people to get the most of their LT1. Advice from vendors who are trying to make a sale need to be taken with a grain of salt because they profit from your choices. You will get unbiased advice here from people who actually have built these cars, a lot of vendors know about small blocks and LS1s, the LT1 is a red headed step child and a traditional builder will offer poor advice like 10:1 compression.

For anyone to offer advice on your build, you need a to state a budget, goals, and your current mods. Is it auto or manual trans?

Do a search for "cast eagle crank failure" and you will find out why you should not consider a Chinese cast crank. If you insist on a 383, go forged.

A 350 or 355 with good heads and properly specced cam will destroy a 383 with stock heads and any cam. Displacement does not automatically mean more power, it only allows for more air in and out IF the path (IE heads and cam) are there to support it. A 350 or 355 with AI200cc heads or LE2s with a good cam can make 400-425rwhp. A 383 on stock heads can make at MOST 360rwhp. A 383 with AI200s or LE2s can make 425-450. BUT, either one needs to be spun to 6500-7000rpm, and a cast Chinese crank will fail way before that, destroying all your work. A budget 355 can be a stock crank cut 0.010, rods resized for ARP bolts, and new pistons 0.030 over, plus balancing and block work. A 383 requires new forged crank $800, new rods and pistons $1000, plus block work and balancing. It's easily $1000 difference to get a 383, for maybe 20-30rwhp.

HellTeeOne

First of all, building a 355 or 383 LT1 that performs well is not a complex process but like anything else, one must pay strict attention to detail and use the right parts. Unfortunately, the LT1 platform is overshadowed by the LSx platform and to some degree, the traditional SBC platform that came before it; however it shares very little with either in terms of what it takes to build one that performs well.
Due to the LT1's relatively short production life the number of cars equipped with traditional SBC motors and LSx engines now vastly outnumbers vehicles equipped with LTx engines. This among other factors has caused in-depth LT1 knowledge to become something that isn't exactly widespread in the enthusiast community, overall.
Fortunately for you, you're in the right place as there are quite a few knowledgeable people on here. Most don't sugar-coat anything, so don't take it personally, take it constructively.

With that said, we would need to know the following:

-your total budget

-what you want out of it (in terms of power, torque, driveability, dragstrip performance etc)

-what you're starting off with: the overall condition of the car, type and condition of drivetrain, any existing modifications, etc.

If the car is in good running order, it would probably be nice to go to a local dragstrip or dyno and get some baseline performance numbers to know where you're starting.

ahritchie

iTrader: (1)

There's no mention of any head work (where the power is) so you have more research to do. I would also consider going straight to a LS engine swap or trade up to a 98+ for the most potential and aftermarket support unless you are dead set on the underdog/oddball factor of a LT1. Finding competent tuners that will still mess with it is a PITA, unless you spend some big money on a 24x setup that LS1 cars come with for "free". Not to mention the other obvious shortcomings. Not knocking the LT1, just saying for the money of a quality 383 build (5-10K) other options would should also be explored!

Moochdog

Aw ok thanks for the tip. So should I get my heads ported or get the lt4 heads and intake? Since this is my 1st engine build is there anything I should know should I lower the compression I plan on running boost later down the road?

Catmaigne

iTrader: (6)

As cast LT4 heads get the **** kicked out of them by the right ported stock castings. The LT4 intake also offers no flow advantage without porting.

Have you ever put an engine together before and do you have access to decent tools? You need to be able to make repeatable measurements down to .0001" which takes a type of feel to do right. I wouldn't be using plastigage on anything other than a beater.

Moochdog

Yea I've took apart a motor and put it back together in my automotive class I know how to read all of the tools and other stuff and I I've watched people build them on YouTube. And I can get help with the build from people I know. The goals for the car is to make it fast with about 700 hp one day large number I know but worth the try also will be a weekend summer car. As for budget I don't have one I get school refunds and tax from working its a time process for me cause I finish school I'll be ASE mechanic. As the condition the car is the motor leaks oil a little but runs like a horse transmission is strong I've done a few burn outs only up to 130 mph. The only mods I have is a jegs chrome elbow and carbon fiber style pod filter the egr does not work(found that out in class)has no cat with stock headers with flowmaster exhaust

96capricemgr

iTrader: (1)

Stick to simple stuff and if the motor blows throw a junkyard one at it. Your youth and "professional training" are going to combine to cause you to not listen well and make very bad choices.

Everyone wants to build an engine, but the shortblock is the most expensive place to spend money and gets you the least return in HP.
$3000 worth of heads and cam/valvetrain can get you a solid 100+rwhp gain, a 383 shortblock under that will cost usually easily another $3500 and gain you maybe 20-30hp IF done well, it will have a little nicer torque curve down low but a well done 350 with the compression LT1s like should make great off idle torque anyway.

Catmaigne

iTrader: (6)

I would also vote for the junker build. It's cheap, proven, and will give you time to think a bigger build over. The last thing you want to do is hastily throw together some expensive mismatched parts and have it potentially blow up in your face. It happens all too often.

You would need access to decent micrometers (w/anvils), a dial bore gauge, ring gauges, calipers, telescoping gauges, among other things. By decent I mean well kept and gently used tools from Mitutoyo, Starrett, etc with graduations in ten thou. The china tools are really hit or miss... although some of the mics and electronic ones aren't bad. Do you understand how to adjust your measurements to account for calibration? It's not as simple as subtracting a mic value from a gauge value.

superspirit

I dont know where some of you have aquired the info you spread as gospel, but some of it is over the top. as for a junkyard build nothing wrong with that. As for needing all those high dollar tools I call BS! I've been putting engines together for 30+ years and never needed thousands of dollars worth of tools to measure with. a good set of feeler gauges and a good caliper and some plastigauge and you can build them just fine. I've put 9 second big blocks together with nothing more than that and 10 second small blocks. So unless you're just selling tools they arent necasarry.

And dont forget a quality torque wrench.

HellTeeOne

700hp (regardless of whether measured at the rear wheels or the flywheel) is a long away from a stock LT1 f-body. About a minimum of $15,000 away, actually.

If you're still in school, it's likely more financially responsible to dial back your goals to between 400 and 500 horsepower unless you're made of money.

Catmaigne

iTrader: (6)

If you're going to dump thousands of dollars into a bottom end to endure 700whp any beyond then why the hell would you ever want to eyeball your bearing clearances with plastigage? That stuff is only good for double checking. It's great that it's worked for you but that still doesn't make it right. Putting together a small block capable of that kind of power is more complex than slapping together some legos. Blueprint it and do it right the first time if you actually want it to last. A decent set of machinist's tools can be had for only a few hundred bucks if you search around. It's really not that much more in the grand scheme of things.

Moochdog

700hp goal is a one day goal after I gain more knowledge and skill but for now I would like start somewhere around 400 I know about tools some are worth the money maybe snap on but they are all kinda made the same as craftsmen tools. I not made of money I just know to manage money but I had in mind of buying a bare block and go from there and buy parts piece by piece it seems cheaper to do that. But after videos on YouTube the 355 is less work but the 383 is more work plus money. If I do the 355 should I get the hypereutectic piston since there better than cast

Catmaigne

iTrader: (6)

The stock pistons are hypereutectic and are pretty beefy for what they are. If you want 400whp then pick up a low mile junker and slap the right heads/cam on. 355 offers no real power advantage over stock for a typical build and a cheap aftermarket piston could be a step backwards.

96capricemgr

iTrader: (1)

Many gen1 motor racecar owners seek out used stock LT1 pistons because they are light with good ring package. Most budget pistons are not even as nice as stock, one popular vendor was telling guys what PN forged piston to use oblivous to the fact it was 20% heavier than stock. That is a lot of extra unnecessary load on the rotating assembly, and this was an LT1 "expert" imagine how "well" you will do.

CapoThDon

iTrader: (1)

Research research research bro!!! I was basically where you are at besides the fact I bought a LT car with a blown head gasket (94 firehawk for 300 dollars). But I have a stoute LT bottom end, with basically stock heads, 10.5:1 cr cause the machine shops in Hawaii suck. I'm easily 5000.00 in all I have left is odds and ends like install harmonic balancer, headers, WP, intake complete. And drop it, and still realistic looking at maybe 330hp... MAYBE, we will see. Moral is do research, copy someone cheap build verbatim.

Moochdog

What build I do I was looking in to http://elliottsportworks.com I hear they have good head and cam combs for the lt1 but I'm going to price up parts for both builds I would like forged parts for whatever I do I'm think of a twin turbo set up. I found a company http://www.delteq.com that allows us lt1 guys to kinda do way with the optispark and use waste spark coils. Read up on it I think it's worth the buy if you ask me

96capricemgr

iTrader: (1)

Delteq is failure prone and I thought defunct. You are well off track