LQ4somona

What rod and piston combo am I going to have to run if I am going to get a compression ratio of 8.75 to 1? This engine will have thermal coating from swain tec on the pistons, combustion chamber and down the exhaust ports. Would a set of 6.0 inch rods leave me with enough space to end up with this compression ratio? I don't want to have to position the piston rings to close to the crown of the piston. Also are there any cam suggestions? Where should a guy look for an intake to work with these heads? Help. <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" /> getting fustrated trying to figure this out.

1CAMWNDR

iTrader: (21)

The compression ratio can be had with custom pistons. You should probably get forged ones anyway. Just tell the piston manufacturer what your desired compression ratio is. But I must say that the combustion chamber on C5R heads is so small that you may have a very hard time getting it to 8.75:1.
The rod length will be determined by what stroke your crankshaft has. If it is a stock crank, you can have a 6.225" rod. At any rate, I think you can have larger than 6.0" with almost any stroke crank.
You said it will be a stroker, what bore? Kinda need to know what your cubic inch goal is. With that said; the cam should be pretty damn big for those heads on a 400+" motor. Maybe a 260°/254° .635"/.620" 115° LSA solid cam <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> . Again depending on what your cubic inches ends up being. I would want a lot of bore also to help increase the size of the combustion chamber.
The intake manifold will need to be custom fabricated.
Hope that helps. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

<small>[ February 18, 2003, 07:12 PM: Message edited by: 1CAMWNDR ]</small>

Richard@WCCH

iTrader: (3)

Your gonna have to get more specific with crank stoke length in order to figure out rod length and piston crown thickness. Either way, with the small C5R chambers the dish in the piston is going to be substantial.
For an intake manifold, you should try contacting Hogan's Racing Manifolds in Santa Maria, CA. www.hogansracingmanifolds.com
They make make sheet metal intakes for a number of guys running blown LS1's.
As for cam suggestions, you'll need to be more specific about what/how you intend to drive the car ie. street/strip or track only. Hydraulic roller or solid? A little more info please...... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Richard <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

hondakiller

iTrader: (3)

im no expert but there isnt much need to go super huge on the cam for a twin turbo motor. lingenfelter uses a cam barely bigger than an 02 ls6 cam for their 427tt and it makes over 860hp.

ls1290

iTrader: (20)

The C5R heads have 38cc chambers. On a stock bore or 3.9" and stroke of 4.0, -24cc dish pistons and a gasket 0.072 would still leave a compression ratio of 11.3! Going with a bigger bore will only increase the compression level. I have not heard of a dish piston bigger than -24cc. C5R heads are NOT FI friendly.

marco383

Your C5R heads are overkill and an unnecessary complication on a turbo motor. As stated above, 20+ pounds of boost on a good set of LS6 heads with 415-427 cubic inches will get you within sight of 1000 hp. Need more?

1CAMWNDR

iTrader: (21)

Maybe you are right that that cam might be big for a turbo 427. But I thik Lingenfelter uses way small cams. They of course make up for that with heads and other stuff.
I say some Stage III LS6 heads with 2.08/1.60 valves. Hogan sheetmetal intake. And I like a lot of cam, but we need to know if you want to go solid or hydraulic.
<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Nasty N8

iTrader: (33)

We also are offering a custom Sheetmetal Intake for your application. They start at $1700 for the LS1. I do believe the C5R heads are a little overkill for a turbo car. E-mail for details.

Nate Bonham

CHRISPY

Just run LS6 heads and get a short runner custom intake <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Chris

Pro Stock John

iTrader: (34)

Might want to contact LPE, that pewter C5 owned by Steve Dumler has a C5R longblock and runs twin turbos. I doubt the car has a small cam now.

LQ4somona

The engine is going to get a 4.125" bore, which will be done with a sleaved block, probably from ARE, and a Callies 4.00" stroke. I am going to go nuts with the thermal and antifriction coatings in the engine. My main reason for wanting these heads is to be differnet, and because once everything is assembled and in the car, I want to do One lap, and stuff like that. I am thinking solid roller camshaft. Probably go with cam, lifters, push rods, valve springs, retainers and locks from Comp. Jesel shaft mount rockers more than likely to. Thinking that the block is going to be O-ringed, making it safer to run high levels of boost. I have easy access to 100+ octane unleaded fuel, so I can get away running a few more pounds of boost then normal. What type of horsepower would a guy be looking at with 20 lbs of boost? Now once this is sorted the problem is going to be trannys <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />