top3598

wanting to build lsx 427cu or bigger to replace my 525 cu bbc, what kind of power can be made for 427 - 480 cu in with carb, dom. on gas or alky

G Atsma

Based upon the info given, quite a bit!

speedtigger

iTrader: (16)

It just depends on your budget and any other practicsl limitations your application might have. Dart built a 400" LS that made 1166 hp at 10,300 RPM.

Doug G

What HP is the BBC that's getting replaced ?
What HP you looking to build ?

Seeing some of the builds on here, I don't think you'll need that many inches

axe murderer

iTrader: (3)

800 with a poor intake
http://www.enginelabs.com/news/video...7-on-the-dyno/

speedtigger

iTrader: (16)

That article seems to be tragically short of details.

top3598

thanks speedtigger, yes the budget will allow alot but not looking for that much, have picked up lsx short deck block and set of used ls7 heads complete for pennies,
i'm a old school t/s racer and sold my 632 and build 525 for daughter to continue bracket or heads up racing, so have little experiance in ls stuff, we made around 800 hp on 525 but if i can make or even more with the lsx stuff , it removes alot of weight from frt of car.
so my questions and i know it so broad on how much power can be made with the ls stuff [ without breaking the bank, or just keep bbc in it and sell ls parts] and what type of rotating assm. would be need and suggestions on cam shaft, manifold for carburated deal. any help would be appreciated

top3598

thanks axe murderer for video, sounds very good
have cast lsx short deck , and complete ls7 heads, was told 800 is fairly easy to make with ls stuff and carburated, just looking for some information and guidance what it takes to build that type of hp.
camming and whos and what manifold work best or sending one to be ported also
compression ratio
appreciate your responce

NAVYBLUE210

Custom Cam Motion LLSR,
CID Intake (Carb)
Two places to start.
Compression depends on fuel obviously, (E85 or Race Fuel)

pantera_efi

iTrader: (1)

Hi 3598, I work with Carl Wegner, with MY reports of 650-700 HP as common depending on Cam Duration/Compression.

I have stock of the GMPP LS-7 Intake Manifold.
I have stock of the Wegner Water Pump "pictured".
I have stock of MY IGN-8 Ignition with GEN-IV coils OR IGN-1A coils.

I would fit one of my 4.10" forged crankshaft, forged rod, forged piston assemblies.

I would fit a Crower Cams SOLID roller AND fit Lash Caps to the exhaust
valves now allowing Lash Adjustment with OEM LS-7 rocker arms updated with CHE's.

Lance

CAMMOTION PERF

I think a 13.5:1 440" engine is a perfectly reasonable combo cost wise. Throw on some cutting edge LS7 heads and intake and you can make 800 for sure.

My personal street car engine made over 700 HP on pump gas and I drive it all over town. So, 800 for a racecar won't be a problem.

We can certainly help you with your camshaft once you get your heads and intake selected. Just reach out to me when you are ready!

~Steven

axe murderer

iTrader: (3)

I think it was originally in Circle Track but is now on Hot Rod's site, 3 part series but still seems like they lost some in the site move.
http://www.hotrod.com/articles/next-...n-race-engine/
http://www.circletrack.com/enginetec..._build_part_2/
http://www.circletrack.com/enginetec..._build_part_3/

ZONES89RS

iTrader: (25)

427 cubes, a nice CNC program on LS7 castings, solid roller with compression should see 850 without trying.

helicoil

iTrader: (104)

I would suggest more cubes than 427 to easily reach your goal. To do it with a 427 you'll need to spin it high.

Minimum 440, 454-474 would be a lot easier. A 4.350" stroke works well in a tall deck block. Keep the RPM's down below 8000. Shouldn't take but off-the-shelf-parts with a quality assembly job!

https://ls1tech.com/forums/parts-cla...0-hp-sold.html

top3598

thanks for some insight to producing 800+ hp, only problem is i can't go that big only have short deck lsx block unfortunately,, not by choice thats what the deal was and really cheap, along with the ls7 cnc'd heads complete with rockers for $1000. so we are stuck with block. guess well have to use the 4.25crank and either 4.185 bore or all the way out to 4.200, but worry about wall thickness at that bore. yes don't want to turn motor 8000 to some make that power if it can be made lower don't want that kind of maintainance. just something to make as much as my 525 bbc single 4bll on alky. but lighter.

TTur1996

Do yourself a huge favor. Keep the big block. What will you save weight wise is about fourty pounds. To get 800 plus HP out of an Ls NA will cost you more to build than a big block. Big time. That is if you want it to stay together. It will also be Max effort too. A big block will sneeze and make 800 plus effortlessly NA. On pump gas too. There really is no comparison. No different then trying to get 800 plus out of a old school SBC. But I guess the people with the dynos can make it put out as much HP as you want it to, whether it does or not.

Doug G

Build it for boost, add a hair drier, and turn it up as needed/wanted when you want more.... ?

speedtigger

iTrader: (16)

Here is an 800 hp 369 cubic inch LS from Venom Racing Engines featuring a Cam Motion camshaft (shameless plug)

AnotherWs6

iTrader: (17)

Spun it to nine grand though. Impressive for sure. But I dunno, 525 inches...... going to give up 100Ci rev it to the moon and make what he makes now. I don't get it. LS7 stuff is evil for sure. Just hard to beat an old school well put together big block for NA drag racing. Especially when it's already been poked and stroked.

TTur1996

Look how bad the torque drops off when they spin it that high. Seems like the torque was pretty low all along for a 12 degree motor. The only reason to build one of these expensive motors is because they start out as 15 degree and now the Ls7 is 12 degree. Looking for more torque than the tried and still true old school SBC. Which you can build for half the money of a LS. And still make as much power as that. A big block at 800Hp would be putting out like 700 ft pnds of torque or more. That would be at like 6000rpm too. A big block only putting out 800Hp would last for a very long time also, being its not even close to being Max Effort like the Ls would be. Really No Comparison at all.