Nidal N

Hello ladies and gents. In the ongoing quest to blow tires with a single press of the accelerator, I'm moving on to forged internals, and wanted your advice on solid brands to use.

A little history: I put a procharger D1Sc in my car (96 LT1), temporarily set it to a low 8 pounds of boost because the engine is at 70K miles. Exhaust is done (long tube headers, to y pipe, 3 inch all the way), transmission is done (yank 3400 stall, rated to 650 HP). Suspension/body stiffening/brakes/fuel pump are all upgraded and done. Time to get forged internals so I can crank the boost up. (aiming for aroung 600HP-650HP at the flywheel to start... with possibly more in the future, so I want parts that can handle more). Looking for top and bottom end-- camshaft, pistons, rods, valves, etc. etc. etc. The whole 9 yards. I figure I'll get it all done at once and not have to worry about it in the future.

Any recommendations on which brands to source the parts from? I have no idea when it comes to this stuff, and the mechanics who will be doing this don't normally work on American cars (I'm in Europe, and these guys typically work on 4 cylinder turbo track cars--very nice work, but not LT1's), so they asked me if there were any brands I preferred.

So, reading up as much as I can, I've come to the following:

Mahle, set of forged Pistons/Rings/Pins/Wire locks: $700-$750

Callies Compstar Rods, $650 or $1000 or $1600 depending on application (I'm guessing I don't need the super-heavy duty... but if anyone can verify, I'd appreciate it)

Elliot Sportworks complete top end with custom crankshaft: (around 1-2 grand, depending on which cam/heads setup I go with.) Company seems to be highly recommended on LS1Tech.com boards.
http://elliottsportworks.com/

Which weight of injectors should I be using for a project like this? $300-$400

And, of course, add the 2-4 grand parts bill to whatever labor is involved.

My question is, am I missing any major components which need upgrade that I should be having added NOW that the motor is coming out of the car? (things like pumps, pans, etc?)

Thoughts? Experience? Warnings? Recommendations?

Would there be value in doing the 24x mod at this point, or is it easy enough to do that in the future if I ever decide to do so? I'm going for a car that's street friendly, but can tear it up.

Thanks for any advice! I appreciate it.

SwampWS6

iTrader: (7)

I have Mahle pistons, rings and Scat forged rotating assembly. I think Compstar is a lil bit better than what I have, I just wanted to save money at that point. LE top end kit will for sure put you close to what you want (A great guy who knows his stuff). Injectors I would go the minimum of 60# but I run 80# on my turbo app. 24X would make tuning easier. Its all pros with the 24x, only problem is the $$$ it costs.

Texas Speed, LE portworks, EFI Live Connection, Summit, and Ebay are your best sources. Somebody correct me if im wrong!

Paul Bell

iTrader: (9)

Wiseco/K1 is a very nice kit. I went with it.

ahritchie

iTrader: (1)

Lunati makes really nice parts, pricy though....their cranks are rated to 1500hp If you want something more budget oriented, still able to take 700-800hp Ohio crankshaft makes decent stuff.

Nidal N

Thanks for the leads and the tips, gents! Since I want to keep things simple and make sure things are compatible, I'm looking at an elliotsportworks top end, with a Lunati Sledgehammer Assembley bottom end http://www.lunatipower.com/Product.aspx?id=322&gid=185 Now, since the bottom end kit is a 383, and my engine is a 350, I'm guessing that would involve the shop doing the work to do a bit of boring and such. So assuming they can do the work right, is this it? (I would also need injectors, a tune, etc., of course... but do I need anything else?)

TravisMcGill2000

iTrader: (2)

For that kit ur gona need a 2 piece to 1 piece rear main seal adapter. If you plan running some decent boost. Then id look into a dished piston.

TravisMcGill2000

iTrader: (2)

Far as machine work. Your gona need the rotating assembly balanced, bored, clearanced for stroker, and blocked decked. In sure im forgetting somethings but it probly gona run you aleast 1k in work.

PA94Z

iTrader: (1)

Here is a nice rotating assembly:

http://www.cnc-motorsports.com/rotat...h-pistons.html

I am unsure what compression ratio you will be needing, but that kit would have you around 9:1 static compression with a set of Lloyds heads which are normally around 54cc after milling.

Lunati makes nice stuff, but I like the Compstar line by Callies - it's whats in my motor. Also, If you are really going to be hammering on that motor it would be a good idea to go with the HD rods.
These-
http://www.cnc-motorsports.com/conne...ting-rods.html

The website I linked will taylor the "kit" to whatever you want. If you want to change the pistons and get a custom dish for a different CR they can do that. Upgrade to the HD rods, get a special ring package etc.

Catmaigne

iTrader: (6)

Street car or track car?

I would reuse the stock crank, get some 4340 Scat I beams w/7/16" ARP bolts, and a decently thick 4032 piston if the boost isn't crazy. Studded 4 bolt mains too. Add a decent flowing top end and you'll have no problems.

Check out the build in my sig, it's a budget minded 355 built for boost. I should be putting the motor together within the next few months.

Nidal N

GREAT link! I was about to ask about the compression ratio. Question: what is the difference between a 1 piece rear seal and a 2 piece rear seal?

Also, what's a good bore for these engines that would keep them safe? I would imagine I really shoud go .030 over, since the engine is 75K miles old and I want the piston walls cleaned up. Is there any real value in going more than that considering I can blow it to scary levels without all that?

And just to make sure I'm understanding all this, I'm starting with a 350, and boring it .030, thus it'll become a 355. It's the crankshaft which determines the stroke which really gives it the bump up to 383, right? Any other "digging" into the block to adjust for clearance is done by the shop.

I very very much appreciate both the recommendations AND especially the education! You guys rock!

Catmaigne

iTrader: (6)

LT1s and other SBCs past 1986 have a 1 piece RMS.

Typical overbore is .030". 3.48 stroke with 4.030 pistons is a 355, 3.75 stroke with 4.030 is a 383, 3.875 with 4.030 is a 396, etc.

There's more to your build than just throwing a high dollar rotating assembly into an old LT1 and calling it a day. I can't make a good recommendation based on the information given. Is this a street car or track car? What's the ultimate power goal beyond 650 hp at the flywheel, i.e. how far do you want to go? How much boost and RPM max? Will you be running an intercooler and/or meth? Pump gas or race gas? Reliability or max effort performance? You'll be pissing away money with that fancy rotating assembly if your goals aren't super high, it could be overkill. There are a few guys making more than that kind of power with stock crank and rods np.

Things to consider:
Stock vs stroker cranks (more stroke means higher rate of piston acceleration and more stress on EVERYTHING)
GM vs aftermarket cranks (chinese forged cranks can be questionable, I've seen a 4340 eagle with a broken snout)
Long rods vs short rods (longer rod means more dwell at TDC and less detonation)
Rod bolts (depends on RPM range but ARP 2000 preferred over 8740)
4032 vs 2618 forged alloy pistons (I could talk about this for hours, but 4032=street)
Piston top land and crown thickness (deep dishes make things thin, be very careful)
Piston compression height (too thin means the pin will be very high up, crown is thin)
4 bolt mains are a must (splayed or straight would work but stock caps are weaker grey iron, steel preferred)
etc.

Money1

Check out Crower.

Nidal N

Catmaigne, thanks for the info. To answer your questions:

The car will be mainly street driven, but wih a few track days a year.
I'd prefer a more reliability as opposed to pure speed at al costs.
The SC has a twin-core intercooler with an air scoop I may replace with a fan for clearance issues.
I'm not doing the 24X swap at this time, so max RPM's will be 5800, I believe, though I may do the swap in the future and raise the max RMP's.
I'll be on pump gas.
I just want enough boost at the moment to get me to my 600-650 goal, while keeping the car as streetable as possible. I'll leave the exact amount to the rebuilders.
In the distant future, I want to pump it up beyond 1000 hp just to have done it. At that point, I'll hardly drive the car, so the ridiculousness of doing so won't matter.

And as far as pissing away money... the whole car is pissing away money. I'm not a millionaire (or I'd have the new porsche 918) but I do have enough to spend a few extra bucks to get a bit more reliability out of the equation, so I really don't want to cut corners. I also want to make sure that what I do it futureproof so I never have to do it again when I go for more power. Plus, it's REALLY hard to find anyone who can do this kind of work out here (I'm in Europe), and I'm traveling a thousand or so miles to have this work done. I'd like to make it as bulletproof as is reasonable. Or, to sum it all up as my wife would say: "What's wrong with you?!??!"

Catmaigne

iTrader: (6)

The hardest decision you're going to have to make is piston choice because you're on a very fine line between street car and track car with that amount of power. You have 2 choices of forged pistons: 4032 or 2618. 4032 is the more street oriented alloy and has a higher silicone content which helps it retain its shape over long periods of use. This is what's in all boosted OEM applications because they last longer and expand less (meaning they slap less when cold). These pistons are harder and more brittle which makes them less forgiving to detonation (you can break chunks off and blow holes in them with too much boost). 2618 is more suited to a high boost track car that doesn't get much street use. The silicone content of the piston is much lower than that of 4032 which means the piston is softer and will take more abuse without breaking into little pieces. The problem with this alloy in a street car is that they'll slap like crazy when cold because the coefficient of expansion is much greater and they won't last nearly as long. I've heard they only go for about 30-50k miles before they deform and the ring side clearances widen which results in a loss of compression. Neither piston is "weak," it all depends on what you plan on doing with them.

4032 = longevity but less boost
2618 = short term but more boost

Having to tear down my motor more frequently and more piston slap was a total turnoff for me so I decided to go with 4032 pistons in my build (Mahles). I'm trying to make up for running less boost by upgrading the top end to something more extreme without compromising driveability. You can do the same with more displacement (383 would be safe), more RPM (LT1 computers are good til 7k), more flow (bigger heads/cam). For you, 1000 hp at the flywheel is a tall order on pump gas but it's doable even with 4032.

5800 RPM will take too much boost to get to your goal so I'd definitely go with a bigger cam. If you're upgrading the mains to 4 bolt and the rods (which will probably have nice ARP 2000 bolts in them), I see no reason not to spin it higher. Just don't go crazy with lift because it's hell on your valvetrain.

A cheap alternative to the cast stock crank is the forged 1053 GM unit you'll find in LT5 engines, GM crate motors like the ZZ4, and some heavy duty Vortec trucks. This is the one I will be using when my motor is together, I forget the casting # (it's in my build thread somewhere). There are debates over the strength of 1053 compared to 4340 (1053 is weaker) BUT you have to remember that cheapo 4340 cranks are less beefy than an OEM GM crank by 5-10 lbs. I doubt there's much disparity between the two.

For a 383 I would skip the budget Compstar stuff and go straight to Callies or the like. I'm not sure if I trust the snouts of a 4340 crank not to shear with a blower or at least eat a main bearing. Also, you don't want too long of a rod because it will decrease your piston compression height. I remember hearing 1.3" was the minimum you'd want, mine are 1.425". You want a good balance between rod length and height.

Nidal N

It'll be 4032 pistons, then. Thanks for all the input! If I do go with callie's, I'll call them up and see what they say about the strength/price difference between compstars and their other brands. The 1000 HP thing is a wild idea for way in the the future. I'm sure 650 will make me more than happy (and make me need to change my pants).

I'm a bit confused about one thing. I thought LT1 computers were somehow capped at 5800 RPM. I thought you literally couldn't go above that without doing the 24X swap, no? I'd love to go to higher RPM's... especially with these components. But I didn't think it was possible on the LT1 computer.

Edit: Never mind. Just did some more googling and they can indeed handle 7000-7200. So let's say I decide that 7000 is the limit. Does that cause any problems or change anything? Or is that just added revs = added power at lower gears?

Edit#2: So I see in your LOLT1 build you're looking for 60 pound injectors. Online calculators are telling me I need the same. Have you found what you're looking for? What would you recommend? Are there any issues with larger injectors to worry about? I have a high volume fuel pump... but I have no idea HOW high volume. Hoping the shop that's going to do the install, can test the flow rate and let me know if I need to upgrade.

PA94Z

iTrader: (1)

The stock LT1 computer can go 7000 RPMs when tuned. There are no fuel and spark tables beyond that to modify. More RPM require quality parts to stay reliable. A good valve train setup will be key. Lloyd can help you out there. I would strongly recommend talking with Diamond, JE or the likes about piston choice and material.

Catmaigne

iTrader: (6)

The 5800 rpm cap is for the Vortec 350s. LT1 is 7k.

More rpm capability means you can run a larger cam with more duration (and lift) to make power when the cam peaks. You'll have a wider powerband and move more air which equates to more horsepower. However, there is a point of diminishing returns where if the cam for your setup is too aggressive then you'll lose power and torque in lower rpm ranges. You want a decent sized cam your setup can support but won't compromise driveability, this is usually in the 22x or 23x duration range. The cam also needs to have very little overlap for a blower or it will hurt your boost (0 to 5 degrees).

Overlap = (advertised intake duration + exhaust duration)/2 - (LSA * 2)

Catmaigne

iTrader: (6)

I was looking into some 60lb Siemens injectors because I know they have the correct plug. Haven't decided what I'm going with yet, I still need to upgrade my fuel pump(s). I only have a single 255 in there now.

Rob94hawk

iTrader: (1)

This.