frenchsquared

I currently have a basically stock engine, LS1, with a Si-Trim from A&A corvette.
SW Headers, No Cats, 10lb of boost.
I'm at 590 rwhp.

I want to start planning a 418 or 427 that will get me to 900hp range.
Yes, I will add a larger blower after the engine is built if needed.
May also add some spray to it, but I am hoping I wont need any.

I'm not into 1/4 mile. I might try a few passes but this is a road course car.
This engine needs to be able to handle 30 minutes sessions not just 9 sec passes.

I know almost nothing about LS engines so I am look for options so I can
start learning about the best internal pieces for my set up.

Want to run pump gas.

Looking to spend $4500 to $6000 on the bottom end.

Can you all get me pointed in the right direction?

Thanks.

chevyrunner

iTrader: (4)

im not sure if you are saying you want to build around the ls1 so ill start by saying you will not reach 900 flywheel horsepower with a ls1 unless you twin turbod and added nitrous and i dont know how to even go about telling you how to do that..

best bet is a stroker. start with a 6.0 block or 6.2 block. have it bored out

if you have the cash go ls7 block and heads as it will be a little easier to make a higher hp number.

nitrous is going to have to be used or as you stated a blower/turbo.

900 crank hp is around 650-750 rwhp depending on drive train

to support that youll need a forged crank (i have seen stock cranks go as high as 1000hp but who wants to take a motor apart if a crank breaks)

recommend h beam rods but not required. a set of forged i beams are ok. scat and callies make good choices.

heads are key.. ls7 flow the best followed by ls3, you can use stock of either just have them machine ported, i know people will say you can make the same power with cathedral heads but i dont agree and have yet to see a cathedral port head out perform the equivalent square port head

have some pistons custom made to match the heads i.e. go dome if you can. higher compression equals higher hp

have martin or someone spec you a cam to match it all
finally decide if you want to stay efi or carb'd

carb will probably gain you some more hp but how much is debatable, efi go fast 102/102

hope that helps...
good luck

NAVYBLUE210

Look at ERL website at their short blocks to see what you need to do
To get aluminum block to live at that HP especially on a road course!
Otherwise factory iron blocks are less expensive to build but will
Cost you 100+ lbs at the front of the car weight penalty.
You will also most likely need a "Real" Dry sump for the engine to
Survive and not the POS GM factory C6 pseudo dry sump.
There are a couple of 600+ HP NA 427-440 LS Engines set up for
Road Racing in the GenIV section do a search and benefit from
Their experience!
Good Luck!

frenchsquared

I am thinking LS3.
Must stay aluminum.

I did not specify LS3 because I don't know if it is the best base to start with.
Someone told me LS2 was stronger.

Everyone tells me the Fast intake is a waste of money with a blower.
I already have an LS6 intake, but I don't know if it will fit LS3 heads.

I want 900 rwhp.
A simple cam swap will get me close to 900 fwhp.

I am not going carbed.

NAVYBLUE210

LS6 intake fits cathedral heads will NOT! Fit LS3/ square port heads.
LS3 block with 4.0 crank will get to 416 CI.
You could use LS6 intake W/ ported stock or aftermarket
Cathedral heads, TFS 235s would work well W/ 416 CI, FAST 102
W/ LS3 TB (90mm) probably worth 60-80 horse @ 10lbs of boost
vs LS6 Intake & stock TB on an engine that size!
Probably swallow 2-3 pounds of boost at the same airflow.

frenchsquared

Im not buying new headers. Just spent $1500 on SW headers.

Will they work with any heads, or will they limit my options?

NAVYBLUE210

If the headers are designed for C5 &/or cathedral heads then, TFS 235 or
AFR 230 would be the best heads IMO for a 4.060 bore size or
Smaller especially with a 4.0 stroke. I do not know if those headers would fit square port heads.

frenchsquared

I think the shop told me to get 235. I will probably jsut get AFR heads.
I have them on a few other cars and love there heads.

Right now I am trying to figure out the block.

So the corvette forum say I cannot run a 418 at 4k rpm for 30 minutes during a road race. Why?
I see no reason why an LS3 based 418 cannot be built to run 4k rpms all day long.
Seems it should be able to run 6500 rpms all day long if built correctly.

What pistons?
What Crank?
Ls3 or Ls2 Block?
What rods?

Is there a better stroke to go with then a 4" since I road course this car.

They sure high... its $6k not counting the block, thats another $1500.
http://www.erlperformance.com/gm-ls-...e-short-blocks

I'm fine with that if there is a reason.
Several other shops offer the same thing for a lot less.

Jimbo1367

But are the **other** shops doing a LS3 based 427? (stock cylinders)


If you are going to road coarse this and dump major coin in a ERL dry sleeve stroker, I make sure you consider going to a aftermarket dry sump system. It would SUCK to suck the stock oilpan dry during hard road coarse driving.

NAVYBLUE210

Tony Mamo is the man to talk with regarding AFR heads, He did a road
Race motor a while back 434 W/245 heads so 418W/230 heads would
Be ideal, Callies crank&rods 4.0 & 6.125, pistons by Wiseco (J&E, Diamond
Others make quality ones also). Oiling becomes critical on road courses
W/ High G Loads that's why investing in a real Dry-Sump ~$3K+
can save your $10-15K Engine!

frenchsquared

I always planned an external oil reserve and oil cooler.
I have not researched Dry sumps, but I know it will get one.

Need to plan the engine before I plan all the supporting mods.
Everything in regards to oil and water will be replaced and upgraded.

Everyone seems to agree on these parts:
LS3 based 418
230 heads - what are these stock on?
Callies crank and rods
Wiseco Pistons

NAVYBLUE210

230 refers to the size in CC for the AFR cylinder heads. They
Make cathedral heads in 210,215,230,245, and perhaps 255.
On a 418 N/A Tony built an Engine W/ 230s that peaked 660+
crank, 580 rwhp @ 6600 rpm, carried hp to past 7K, with explosive torque (do a search Jeremy's Engine I believe) had 500 lb ft @ 3000 rpm if I remember, Pump gas 11.4:1 comp. Bigger intake, heads, cam, and exhaust
Will reduce boost (measure of resistance!) but increase airflow &
Reduce heat, 9.5-10.00:1 comp with efficient inter cooling and
7-10 lbs of boost could produce 800+RWHP.
Cheaper with ported LS3 heads and stock ported LS3 intake &
Stock LS3 90 mm TB. Not necessarily better but considerably
Less $$. That much power in aluminum Needs ERL, OR RED
SLEEVED BLOCK and all the goodies, or very expensive aftermarket
Al block RHS,LSX, DART etc. Especially road course.
To get to 900 RWHP will take at least 10-12 lbs of boost maybe
15 that's ALOT!, on a road course,now you need meth injection,
Or 100+ Octane. Simple is better.

NAVYBLUE210

Actually if you are going sleeved any way go 4.155 bore now at
434 CI use WCCH LS7 heads with Ported Factory Intake that combo
Is much less $$ than after market cathedral & ported Fast and probably
Worth 50+ HP between the 16 extra inches and much greater!
Airflow through heads and intake, less boost also.

frenchsquared

that helps... wow that is a big cc number.
I'm use to old SBC. Im a huge fan 53cc heads.

Im pretty sure I need to stay below 10.1 with the blower.
And probably 9.1.

At least now I know the CC so I can research the best heads to
get the compression ratio I need.

I will race with meth and 100+ octane.
But I don't want to have to run 100+ octane all the time.

I'm not apposed to using a smaller pulley on the dyno or some spray to break 900hp.
Then going up with the pulley to reduce boost while road racing. If 850 hp
is $7k less, I think I can live with 850 hp, then throw some spray on it as needed.

frenchsquared

wont a 434 be to hard to cool.
I thought a 418 had thicker walls and cooled better then a 427.

frenchsquared

Is seems I could just get a forged 383 based on an LS1 for $4,000.
Get a good set of heads and lower my pulley to break 800 hp.
Then add 200 shot of nitrous and break 1000 hp.

I know you don't autocross with spray. I would only use that on the dyno and
for 2 or 3 1/4 mile passes just to get some slips.

Would that 383 hold up longer then a 418?
Seems it would run cooler if boring an LS has the same effect as boring an old SBC

I don't care if when racing I am at 750, 850 or 900 hp.
Any of them are more power then you can keep on the ground.

Tuskyz28

Sdpc offers a 383 LS based shortblock called the budget buster for 3500 bucks.

frenchsquared

So... is the 383 a better solution for road course then a 418?
I really don't care about $1,000 if the 418 is a better solution.

SDPC website says $3,995

The Budget Series 383ci LS6 is built on a new LS1/LS6 aluminum block and fitted with new Eagle crankshaft, Manley forged pistons, Total Seal Ductile Moly rings, Scat H-beam 6.125" forged steel rods, Clevite main and rod bearings, Durabond cam bearings, torque plate honed and professionally assembled.

I could use my heads, or get 230's, add a nice cam and break 750 whp.
Then add a 150 shot to break 900 whp.

Tuskyz28

Wow!! It went up since the LS fest. When I was there they told me 3500 bucks.

Tony @ Mamo Motorsports

OP,

If you decide to do a 4" - 4.125 bore block I'm getting close to releasing a new Mamo Motorsports 235 head....Its perfect for a stout 402 - 427 CID engine combination if you're looking for a really flat torque curve that comes up quickly and carries well till 7200 or so with the right supporting mods.

I have a few projects in the works right now.....that head and the smaller 220 head I'm also going to release (more aimed at 3.900 bore engines) I'm pretty excited about....I think they are really going to up the bar a notch in cathedral performance, the key to getting the most out of them however is getting the rest of the combination correct as well.

In out of the box trim it should offer results close to the AFR 230's that I have "Mamofied" in the past like the engine build Navy Blue mentioned which I built a few years ago. It was really an exceptional piece but like most engines that produce above average results, it was a well designed optimized combination that left few stones unturned in an effort to get every last pony....aka it wasn't a budget build.

https://ls1tech.com/forums/dynamomet...is-dyno-s.html

For the guys wanting more my new 235 head can also be hand finished for even larger performance gains....just depends on the budget you have to work with. IMO this head is really ideal for a 416 LS3 based combination and I'm planning on dyno testing one of these with this new head early in 2015 (and will likely sell the complete engine after all the testing is finished up).

Cathedral heads are still alive and well....especially suited for the heavier hot rods that want good N/A performance in the lower/middle RPM's. A stroker with a medium sized high flow high velocity head like I'm discussing produces an exceptional power and torque curve and it feels even better in the car.....they are just explosive combinations to drive and traction in the lower gears is a serious problem

Which I'm thinking is mission accomplished

Cheers,
Tony