borderm3

Hi Folks,

I am doing a Hot Rod build here.

I just purchased the following new:
LS3 Rods - $200
L92 Pistons - $200 (I believe these are L92 since they have the valve reliefs)

I plan to purchase the following to supplement above:
GMPP LS3 block - $1500
GMPP CNC Ported LS3 Cylinder Heads - $1200
-OR-
GMPP CNC Ported LS9 Cylinder Heads(Less moving mass) - $1600
Custom Grind cam ~500-600hp (I am interested in higher RPM power for road track use, the chassis can only accommodate 255 wide tires, therefore this would be much more controllable)
Fast (Or something better/cheaper??) Intake manifold for higher rpm
Electric Water pump (machine my own plates unless there is a cheap solution)
Electric Power Steering pump from Mini Cooper 1.6L

If I buy an LS3 crankshaft will it be already balanced close enough to run 7k rpm?

As far as I can tell this is going to be cheaper than the following used setup:
L92/L94 long block - $2.5k
L92/L94 complet engine - $4k and stripping it down.

BODUKE

Get a Rick Crawford ls3 intake, don't waste money on a fast.

borderm3

Thanks, it looks like i have to get a facebook account to purchase one?

Jontall

It will still need to be balanced. The LS3 crank will work well, but I'd buy forged connecting rods and pistons. It will be stronger with Compstar rods and Wiseco pistons.

Jeffemac

iTrader: (1)

How much hood clearance will you have for an intake? If you have the room a SuperVic, Vic Jr., or Holley High Ram will get the "high" rpm performance you are looking for.

borderm3

Thanks for the information, even if I use all GM OE matching parts, it will still need balanced?

redbird555

iTrader: (14)

yes... its not so much about the parts its more about the tolerances each part has. balancing is mandatory with new parts.

also what do you mean by the ls9 head have less moving mass? the heads are very similar between ls9/ls3 the ls9 has a couple casting changes to help with forced induction so if you arent going to run fi then i'd go with the ls3. the ls9 also requires larger dia head bolts....

one thing you havent considered is the machine work. a new block will still need to be finished honed and checked, along with the assembly and balancing of components. that gets expensive really fast. i recommend looking at thompson motorsports, they have a ready to go ls3 short block for 3300 bucks. i know it doesnt seem like it now but by the time you build one from scratch you will be right around that cost and have had to do all the leg work.

borderm3

What I mean about less moving mass - The valves are lighter on the LS9.

Regarding the block building, I didn't realize that a complete new short block was that cheap. I have built many engines, so i don't have any problem building it, in fact it is a nice project to get away from the daily grind.

It's been 10 years since I have had any machine work done. I had my own speed shop then. Will it cost more than $500 to have honing and balancing? I am in North East Florida. I will have to call a few automotive machine shops tomorrow and inquire.

Thanks for the information!

thompson

iTrader: (4)

We can build you a short block likely for a very similar price to what you can build it for yourself with the security of having it built and guaranteed by a shop that does it every day. If we can help in any way please do not hesitate to ask.

Also thank you for the bump redbird555.

1989GTA

That is what I would do.

CAMSTER

iTrader: (10)

Hey Op I'm doing a similar build a ls3 stock block placed shift rpm at 7,100 because mine was a factory build block I did not re balance.

Factory ls3 rods are a lot better than must realize 800 whp no prob with upgrade rod bolts.

I recommend a good harmonic damper like innovators west.

I'm very interested in the electric power steering pump kit set up.

Also what compression and what car you building thanks all the best, David.

borderm3

Kyle,

I will give you a ring tomorrow, thanks for the idea. I have a pretty detailed spreadsheet and like you guys said (and I know from having my own speed shop years ago) it adds up quick.

Chris

borderm3

Camster,

Electric Power Steering -
Thanks for the info. I believe there are two ways to go with the electric power steering - constant advantage and dynamic advantage (My own, now patented terms). I will let you know when I get further with the setup. For ease of use I will just run the pump at a fixed advantage that I feel is suitable. Perhaps later I will build a controller that be parametric based on speed.

Compression-
I am not sure, honestly. My understanding is that this may be complicated question. I have not done enough research to have an answer, although, my concern is that as I raise compression by decking or head gasket size I also decrease the amount of lift/timing available on the camshaft. I would need to consult with someone that has the empirical evidence which is better. Based on how well flow bench numbers are on the GMPP CNC Ported LS3 heads, I would guess that the compression is not the more important thing?
So let me bounce the question back - how thick of a head gasket should I run and what compression would that yield. I was just going to go with factory GM.

Car-
The car is a 97 BMW M3 that I have had since I was a kid back in 2000. I suspect this will not earn me any street cred here, so I purposely left that part vague.

KiwiKid

The standard GM gasket is .053" and I am using a Cometic .040," obviously you can calculate the theoretical difference in compression from the existing elements, if we except those as a constant then I doubt if you are going to see more than 2 points of compression increase.

The thing that we have learnt from our most recent experience [tabled in another thread] is the need to ensure that you copper coat each surface of the 3 layer Cometic gasket, and ensure that a thin layer of Locktite liquid gasket, forms a ring around each waterway as well as between the tops of cylinder sleeve flat's.

I am also building a GEN4 5.3 alloy block engine but fitted with MID wet sleeves bored to 4.185"

Cheer's

Mark.