For what i have seen some of the aftermarket-FI's come with an intake with fuelrails.
I do not realey think that they are going to stop producing the old-style BBC.

What would be the biggest displacement on a LSX?

 

Stock for stock I'd rather have a BBC. Here's why:

-Stronger rods stock. The 7/16 rods are beefy. Yeah it's mass but still.
-Forged cranks in BBCs have taken tons of power even the production ones.
-The smallest production engine is almost 400 CID (well the 366 but who uses one for a build) the biggest is on the virge of 500 CID.
-If you go to an 8100 you can get the coil packs, cathedral port heads, etc. of the original. If you want to retro fit an old school engine the last year of the Vortec 7400 is set up with coil packs I believe. And the same box an LS1 uses too.
-The blocks in BBCs are VERY strong even a production one. Yeah an LSX engine has been run to huge power but I would believe it's more common on BBCs.
-Big cubes. The fact the top of the hill *PRODUCTION* engine is 8.1L and you can take a tall deck quite a bit further than that is rather amazing.
-5 bolts per head. Less sealing issues than an LS1.
-Giant heads. Yeah you can get an LS1 and they make GREAT heads for them. That being said the BBC heads in the afermarket can flow huge volumes for all out vehicles.

I mean the small vs. big block debate is out there, but if you're going to make huge power BBC is probably not a bad choice especially if pump gas power is your desire.

OP:

Since the question has not been asked yet, what's your HP goals? I mean 600 CID is a TON Of cubes. I'm not saying you don't need it (read:big pump gas HP #s) but anything anyone here is telling you is fairly generalized without knowing that.

 

nicew call on those vortecheads nwith the coilpacks , i might need to look intoo that one , only problem i have : the big block i use is a '75 gen I , i have heared about special headgaskets for that problem though

 

My HP-goals are 1000-1200HP.

All the goodies found on an LS1 and more can be found on aftermarket EFI-Kits (Single Coil Packs, Crank Trigger and all the sensors).

They are able to control transmissions and lock up converters too....

 

A basic 540 or 565 with properly sized turbos will produce 1,000 - 1,200 horsepower effortlessly with extremely low maintenance, and will not even come close to taxing the durability or reliability of a forged rotating assembly in an aftermarket aluminum block. If you have the budget available to build this type of engine, go for it. The LSx platform would be a complete waste of time compared to this type of BBC build, especially when taking your goals into consideration. Here is what I recommend:

- Dart or Brodix aluminum block, 4.600" bore, go for the 565. It will cost exactly the same to build as the 540, and will make more low-speed and mid-range torque when out of boost for even better part throttle drivability while also offering improved airflow characteristics through the cylinder due to the larger bore. Avoid World Products castings. The castings and machining offer very low qualtiy considering the amount of money you'll spend, and, as a company, they offer some of the worst customer service and tech support in the entire automotive performance aftermarket industry. Both Dart and Brodix blocks will easily withstand upwards of 3,000+ horsepower.

- Scat standard weight forged 4340 crankshaft. This crank will help keep costs down without sacrificing any durability. Avoid Eagle forgings as they are cross-drilled. Cross drilling is detrimental to oiling system performance, especially at high RPM. Centrifugal force generated at high RPM can significantly reduce oil flow through the oiling passages in a cross-drilled crankshaft, starving the main bearings for proper lubricity.

- Scat or Callies Comp Star 6.385" H-beam connecting rods with ARP 2000 bolt upgrade. Again, these rods will keep costs down without sacrificing durability. Eagle forgings are equally as strong but their threading operation in the rod for the rod bolt threads is very poor, which results in sloppy threads and ultimately reduced clamping force generated by the fasteners.

- CP, Diamond, Ross, or JE pistons. Any one of the four will provide outstanding durability and reliability. CP is the best in the industry, as they offer the most consistently sized and flatest ring grooves among all current manufacturers. This positively contributes to ring seal and ring life. Buy the best set of pins you can afford, and don't get too hung up on tapered-wall wrist pins. Pins flex significantly more than most people realize. Wrist pin flex will prematurely wear the wrist pin bores in the piston and increase friction, resulting in more heat and reduced power output.

- King Pro Series bearings. These offer outstanding wear and conformability.

- Total Seal AP-series ring package. The AP-series is a conventional design (non-gapless) with a top ring that features a special coating to reduce bore wear while offering outstanding sealing characteristics in extreme duty applications, making them a perfect choice for a turbocharged engine that is going to see regular street use.

- Stay with a set of cylinder heads with an intake runner volume no larger than the 325 - 335 cc range. This type of cylinder head design will promote low-speed and mid-range torque when out of boost in an application such as yours as compared to larger runner designs.

- Use a hydraulic roller valvetrain. This type of valvetrain will be virtually maintenance-free, and will offer the most life possible out of your valvetrain components since most common designs do not require significantly high valve spring pressures or spring rates.

This type of build will provide you with a bullet-proof long block that will provide years and years of durable, reliable service, and will have plenty of safety-margin built in should you choose to increase power levels in the future.

 

1000+ passes without changing valve springs or without removing the intake manifold to inspect the roller lifters for wear in the needle bearings? Ok.

While the LSx platform does offer many outstanding features and exceptional strength for an OE design, if you're comparing "stock-to-stock", a GM 4.8, 5.3, or 6.0 cast iron block is generally reliable into the 1,000 flywheel horsepower range, perhaps a bit more with aftermarket main caps. An early GM 427 or 454 cast iron block with 4-bolt main caps is generally reliable into the 1,400 - 1,500 horsepower range, and upwards of 1,800 - 2,000 with aftermarket main caps and perhaps a short fill in the water jackets, although the rear main bulkhead becomes questionable at this power level.

The OEM LSx crankshaft castings are actually comparable in strength to the original GM big block crankshaft forgings. OEM big block connecting rods are most certainly stronger than any of the production LSx rods with possibly the exception of the LS7 and LS9 connecting rods. Airflow charcteristics of OEM LSx cylinder head castings are obviously outstanding. EFI manifolds are a non-issue, as their are numerous aftermarket EFI-compatible manifolds for the BBC that bolt right on and require no modifications what so ever.

All that being said, none of this matters as hannes_slanec wants to build a BBC entirely with premium aftermarket components, rendering any comparison to the LSx platform virtually meaningless.

 

I disagree with the 2 above statements. There have been some stock (later, I think 2004 or so 6.0L) short blocks run into the mid 5's in the 1/8th before bending the stock con rods. Here is one on here:
https://www.theturboforums.com/smf/index.php?topic=104700.0


The ONLY issue with iron LSx blocks above 1000hp is the main caps walking around. Fireball has made 1700-1800hp on a stock LS2 (aluminum) block and main caps (only mod was a little block filler and pinned main caps) before cracking a cylinder wall because he hit part of the VE table he hadn't tuned yet.

 

Very impressive. I stand corrected. I'm somewhat familiar with Fireball's build, but it never really registered with me that he was using a stock LS2 block. 1700-1800 horsepower on a stock block... that's amazing. Thank you for posting those references.

 

not everyone runs 8k rpms and massive spring pressures. 6 years it ran within .02 that entire time. did drop a valve in the end. it got new springs and two of them collapsed first time out in the burnout box. took out the entire engine besides the car and intake and a few lifters. id have to say it was way past the 1000 mark. the last year it ran a rod bearing was checked. looked like new still. my uncle assembled it fwiw.

 

wat turbo's would you recomend for this setup ?

 

@ProJunk

Wow!!!

Sir, this is a lot of information. I copied that on my computer to have it as soon as I need it.

As for the heads, as stated I already got a pair of Dart 320, 2.300/1.880 that I would like to use.

What can you recommend when it comes to the turbochargers and the EFI?

It is always difficult to choose a turbocharger as they got a lot of different parameters I cannot determine.

 

if somebody is using the right parts for a street strip automotive application that should be cake. we put 4-500 hours on the boat motors, and there isn't anything a car can do to that motor to stress it even close to a boat.

i do like your combo you laid out that, is right what i was going to say.

a strait 540, hydro. roller cam, 310 to 330 cc heads, 9.5 to one, with a little boost it'll lay out 1000 hp on pump gas, and if the machine work is spot on it'll live forever in a car.

one thing i might add, this is if the motor will never see high boost but only 10 to 12 lbs. the secret with the 540 prochargered boat motors living so long was instead of running crazy valve spring pressure like normal, run only about 150 lbs on the seat, and a rev kit. keeps from killing the valave springs and the lifters.

 

getting some prime info here thats going to safe a lot of money too , the engine builder i talked to about a 1200 hp turboengine was talking a billet cam for the aplication , looks like a good cast cam will do just fine if im going with the low seatpressure and the rev kit .
will the rev kit be needed on a streetmotor normaly running say 6500 rpm max ? (dunno if the tires frying will cause it to jump though the rev limiter)i imagine those boatengines make a lot more revs when the props are out of the water

 

the billet would be more durable and less to worry about flex or failure. Probably why it was mentioned.

 

your missing my point, there's nothing cheap or corners cut in boat motors. we run nice hydraulic roller cams that run the same as any other, 250 to 350 bucks.
running a rev kit helps change the load of the valve train, not completely replace it, it also adds to the price of the build not less. either way you do it the bottem line is you have to have enough pressure to keep the valves closed.
boats, even stock have rev limiters just because of the fact they get out of the water.

if you want big horse power there's no saving money in building a good motor. you skimp on parts you will have what you paid for, a pile of junk and head aches.

you want to play, you gott'a pay!

 

I think it would be hard to do better than a 540 in a standard deck BBC for forced induction....unless it must be a stock block Mark IV motor. Good size, durable, parts are cheaply available off the shelf. ...oh, and when the engine builder says use a billet cam, listen to him....order it with a pressed on iron gear tho.

 

...oh...and even a fairly healthy BBC 540 without any turbos is going to be too much for hannes_slanec in his convertible on 20" wheels of a death trap to go into, imho.

 

I would defer to somebody more qualified than myself to select the proper pair of turbochargers for your application. My guess would be something in a T4 frame in the 70 - 72mm compressor minor diameter range with at least a Q-trim turbine and 1.00 A/R tangential housing or larger, but I'm no expert on turbo selection. I know enough just to be dangerous. This board is full of people that can provide significantly more accurate turbo recommendations than me. As far as EFI goes, it's pretty hard to go wrong with FAST or Big Stuff 3. The new Holley EFI looks pretty promising also. Based on the small amount of experience that I have using EFI, I think that FAST has some of the best and most readily available tech support, but, again, there's a lot more qualifed indivduals than me on here when it comes to EFI recommendations.

 

I agree 110% for a properly designed street/strip automotive application. I also agree that marine engines are some of the ultimate torture-test devices for parts durability and reliability. I realize there were some generalizations flying around, but when I brought up the point about making 1,000 hits without valve spring replacement or lifter inspection, I was referring to a modern BBC drag racing engine with a typical solid roller valvetrain, which, as you well know, will normally utilize aggressive ramp rates in the lobe design and high spring pressures/spring rates that are obviously very taxing on valvetrain components. You're obviously a person with some knowledge and experience... I think I can safely say that you'd agree that an ounce of prevention is worth a pound of cure in an application such as I'm describing.

Anybody that claims to make this many passes on this type of engine without performing the minimum preventative maintenance is either lying or completely ignorant. In the case of ignorance, they should not be surprised or upset when the engine finally does experience a valvetrain-related failure and destroys their entire investment in that engine, especially considering that standard preventative maintenance practices and periodic freshening of said engine would provide for a usable component life span that well exceeds 1,000 passes by a significantly large margin. A person like this should ask themselves if they want an engine that will provide THOUSANDS of passes with maintenance and periodic freshening, all of which is much more cost effective for their entire racing program, or if they want an engine that they essentially ignore and abuse only to have it basically completely eat itself with minimal if any salvaging of engine components after it experiences a failure. It shouldn't take a genius to figure out which option is the ideal choice, but I've been proven wrong plenty of times before. Some people can fuck up a steel ball bearing in a sand box.

 

A good rule of thumb to follow for cast roller cam cores is to not exceed 500 PSI of spring pressure at maximum gross valve lift. Billet cams do not cost significantly more than cast cams... it's not worth cutting corners to save a few bucks, especially when it comes to valvetrain components. A rev kit is a nice investment in a hydraulic roller valvetrain as the rev kit allows an increase in spring pressure on the body of the lifter rather than at the valve. This prevents the hydraulic plunger mechanism inside the lifter body from seeing excess spring pressure and decreases the possibility of damaging the plunger mechanism. This method also reduces the load on both the rocker arms and pushrods, resulting in less deflection, less wear, increased component life, and less parasitic horsepower consumption.

It's worth noting that one of the fastest ways to kill a set of valve springs is to let an engine free rev for any kind of extended length of time with little to no load on it, especially at speeds over 5,000 RPM. The harmonics generated in the valvetrain occur and change so rapidly in an unloaded free-rev condition to the point where they become destructive. The valve springs are the key component in the valvetrain that absorb and help control harmonics. When the harmonics change too rapidly, the valve springs cannot respond quickly enough to absorb those harmonics, and will quickly lose material integrity and pressure from coil bounce and float induced in this unloaded free-rev state.