D9HP

Wondering what the largest bore is for a stock LS3 head. I saw an article on HotRod.com where they used a Darton sleeved block with 4.815" bore and LS3 heads. Just wondering if that is acceptable.

Seems like you could have absolutely zero out of hole on the pistons, or is there some give?

Thanks,
D

LivernoisMotorsports

iTrader: (1)

The bigger the bore the more a given head will flow. It is when the bore is too small you have shrouding or just plain interference problems. I'm a bit confused on the out of the hole question. Most engine builds require a minimum of .040" piston to cylinder deck clearance. Example; piston is .010"out of the hole = .050"head gasket thickness. Piston at .000"deck you can run a .040"

D9HP

Right on. I guess the head gasket is going to play the critical role if there is otherwise no issues running a larger bore than originally was used. I am wanting to run 11.3:1 compression and am only interested in the LS3 heads because I can get them for around $400 in need of some work but that would at least allow me to finish the build and mockup while I save for the Mast Motorsport 305cc LS7 heads.

Another question, is the valve spacing / location in the combustion chamber the same on all LS series heads? So are the piston's valve reliefs all the same?

KCS

iTrader: (20)

LS blocks can't go 4.815", I think you meant 4.185"? Like mentioned already, you can ring as big as you can fit in the 4.40" bore spacing of the LS blocks.

Also, no the valve spacing is different between the cathedral port heads, the LS3 style heads, and the LS7 style heads. Wiseco is the only one I'm aware of that manufactures "multi fit" valve reliefs to fit any of the LS heads.

D9HP

Yes I meant 4.185" sorry.

Perfect - I was planning on getting Wiseco pistons anyway!

Thanks.

JS01

iTrader: (10)

The bigger the better on LS3 type heads.

WKMCD

iTrader: (2)

FWIW: I ran a 4.125 bore with LS3 heads with a 2.200 inch intake. The very mild 427 made 577/530

D9HP

Wow that's awesome. I'm shooting for something similar to that number.

Were they stock LS3 heads or ported?

I am not planning on doing anything other than a hand port and heavy cleaning on the exhaust side.

577HP is very close to my goal to achieve 500BHP.

WKMCD

iTrader: (2)

That motor has WCCH Stage 3 heads. BTW: Those are rear wheel numbers. It made 656HP on the SuperFlo engine dyno.

D9HP

Apologies!

656HP at the crank is gnarly from a 427! That is insane. I bet that is a handful to get around. Can you give me cam specs you're running, if you don't mind?

Insane insane.

WKMCD

iTrader: (2)

This is in my C5 that I unfortunately totaled on Dec 6, 2013. The good news is that the engine survived along with the CCW wheels, PFADT Suspension, Stage 4 tranny and diff, all leather interior and DD Kenwood/JL system.

The engine and other pieces will be for sale in a couple of weeks.

The cam is a 234-242 but you won't find the lobes in any catalog.

D9HP

Ouch I recall you mentioning it would be for sale now.

Glad you're okay...and those CCW wheels! Love their stuff.

You have something new planned?

Jimbo1367

When I first seen the pics of the wrecked vette, I was hoping you could save/sell the engine. Glad to see he can get some of his cash back.

I wish I had the cash for WKMCD's engine. I know he went through a lot of R&D with it. BAd azz engine..

WKMCD

iTrader: (2)

This is on order. Z51, 3LT, bi-modal exhaust and only 2 pedals this time.

WKMCD

iTrader: (2)

Thanks Jimbo,

The engine just had the top end freshened with Manley springs, valve job, Johnson link bar lifter and CHE rockers. Doesn't burn or use any oil. The whole engine only has about 4k street miles. I'm selling it from pan to manifold for $8k. It would cost you about 15k to buy the same build.

Someone will get a very good deal.

Jimbo1367

WOW Very good deal. Cheaper than I thought you'd sell it for.

WKMCD

iTrader: (2)

I'm not greedy nor am I in a bartering mood.

D9HP

Oh man oh man I absolutely love the C7.

Growing up when the C4 was the flagship Vette really made me not appreciate them very much (besides the C1 and 63' split window) but I have to admit I have liked each iteration since the C5 more and more.

The new one is IMO the best driver's car value on the face of the planet. I haven't driven one yet but was taken for a cruise at the last cars and coffee in Raleigh. Absolutely love that thing.


Unreal deal on that motor. Really wish I was about six months further along and I would jump on it. Should sell quick!!!

Thanks again for all the help.

I'll be sure to keep this all up to date.