rkreigh

I have a 4.8 iron block that I'm considering building with a 4.0 lunati crank and rods, and diamond pistons setup for a turbo with maybe 9.5 to one

here's what I have so far car is a 2003 C5 Z06 vette

AFR 225 heads
ARP head and main studs
crank from 3 different motors to choose from (4.8, ls6, and lunati 4.0)
the turbos on this kit are pretty small but work well for me
I believe they are the 58 size t3/t4 hybrid turbos
127 fic injectors
Haltech ECM with 8 channel EGTs
.82 a/r turbine housing (I think stock is 70 or something like that)
debating the fuel system upgrade, thinking a magnafuel 4303 but those 450 LPH pumps look good

I also have the flex fuel sensor so I can run e85 so I'll need to upgrade the fuel lines and pumps for e85

with the 4.0 stroke, may have said the piston is "too far" out of the bottom of the cyl bore and I'd be better off just running an ls6 or even the tiny 4.8 stock crank wouldn't a shorter piston skirt help here ? is this a big problem, seems like lots of folks run a 4.0 crank, but I don't hear of it in a small displacement motor

my turbos are pretty small and won't support a huge CI well and still run out on top end. so I'm looking to stay in that 370 - 383 as the "max size" anything smaller than that should work ok too

also the car has a 3.42 automatic with a triple disk lockup clutch (build for 800 rwhp, which is about all I need in this car)

I'm shooting for around 900 at the tire set on kill running the meth

I will be using a Halltech ecm controlling the meth injection and thinking about the ECS "direct port" nozzles and plumbing the intake (helps with the distribution using the LS6 intake)

I'm considering boring out the block to around 3.8 or so and I need some advice on the best source for the pistons and the max bore size recommended I'm thinking .060 over is fine these blocks seem pretty beefy!!

also advice on the cam I currently have a "dr phil" cam and I have no idea what the specs are, but it runs well and I may stay with it.

looking primarily for an uber agressive street car that can continue to pop off mid 9s at the track on drag radials with a relatively soft launch

thanks for any thoughts

STAR

iTrader: (1)

I would suggest an ls2 block with stock displacement or lq9 if you want to stay iron. I'd bump up the compression to 10.0-10.5 and choose a dual pattern cam around 226/226 115.
If you haven't upgraded the downpipes switch over to 3".

rkreigh

is the ls2 much stronger than the ls6?

I'm definitely "on the fence" about going with an iron block, but at the HP level I'm at I guess I'm concerned

I've also heard the L33 blocks are pretty good. I got a pile of these iron blocks for really cheap and they are in great shape, but the extra weight and potential cooling issues are also a concern

my LS6 block is likely ok, the engine is running fine but has a low rpm tap to it that sounds like a rod knock engine has been running this way for years and hasn't dumped any junk in the oil or getting worse, so it might be bad lifter are flex plate, who knows. I have quite a few toys so this one is due for a refresh

I did get the 3" champion downpipes, they are a work of art but pricey!

also looking for better 3" c5 exhaust, or may even go "c6 direct shot style" with flappers as I like the mild to wild concept and crooze the car quite a bit when it's healthy

thanks for the advice!!

rkreigh

I'm really leaning towards the small stoke stock crank, and putting in good rods and pistons and staying with stock bore block now.

if the afr heads will still work on the small bore, I think this is the way I'll go

with the auto, I want the power to come in upstairs to allow high boost with less chance of detonation.

hooking up on street tires is always a challenge and my thoughts are rocking the torq curve further up the scale and running boost by speed I can get the c5 to hook and go better without melting the tires

I'm not crazy about the weight increase, so how about a L33 block??

they have a thicker liner and should support boost better than the ls6

or just go iron call it a day. decisions, decisions.


being broke right now is helping with the planning phase

I'm accumulating parts as I can afford them and will be taking a couple of 4.8 blocks to the machine shop soon to check them out for winter build

one will likely go in my 68 vette vert (tt with twin t 60s)

and one will go in the 2003 z06

someone buy my house in Alex VA so I have the $$$ !!!