IPRAVN

Hi, I race an Australian class that must run 6 liter max engine size and eligible block. The block is L98 or LS3 destroked to 6ltr.
I have Race C5R Heads and wonder if anyone has reliably run a block notched for Valve clearance? Ive done this on many other engines but not LS yet.
The class is called 3J Improved Production and is Road course.
Thanks in advance.

http://www.cams.com.au/motor-sport/r...anual/race#3rd

lil john

May need a smaller valve combination (@ most) but it will work with the proper pistons choice( Smaller Combustion Chamber most are 58cc's and Down). I had a pair of LSX CT heads in lay-a-way..... , but decided to purchased GZ Vacuum pump and put the savings in the bank( Totaled over $7200) and I was in $1900 . Power out put is Verified as better than good,but with unethical pricing my love affair has ended. I know you know about the Sheet metal intake or Custom Edelbrock ROX intake with some modified intake 2 heads flanges.

dogsballs

Run a destroked ls3, as you will have better chance of fitting valves in with bigger bore.

Saying that the rectangle heads are pretty good.

Vito.a

I do like the idea of a large bore and shorter stroke, but...

All the Hi-Perf Big Block Chevys used to have notches in the top of the cylinder to clear the 2.19" intake valve. You'll need to mark your block where the intake valve is. You should be able to temporarily bolt a head to an empty block and come in from the bottom and mark the location of the valve, plus get a good idea how large the notch should be. You can then set the block up in a vertical mill and make the notches. If you do not have access to a mill it can be done by hand using a die grinder, just be careful and go slow.
An issue is going to be your head gasket. The Big Block Chevy head gaskets came notched. You may have to use a larger bore size gasket to allow for the notches.

Jimbo1367

IIRC....... GMPP notched the top of the cylinders with one of the COPO engines running LS7 heads on LS3 bore dia.

I might be wrong, but I thought I read that somewhere.FWIW

IPRAVN

I have Notched many engines over the years but never seen anyone do it to an LS.
Yeah Gasket will be an issue.

dogsballs

Can buy the flycut tools and do it with the head and pistons still in block

IPRAVN

I heard today that people Offset Dowel the heads, I can see the reason but can't imagine how the head studs would work?

Steve - Race Eng

iTrader: (1)

That won't work without enlarging the head bolt holes.

Better method is to sleeve the block and offset the sleeves to give more clearance around the intake valves. I have done that a few times for NHRA stock eliminator cars.

Steve

IPRAVN

Ok, I have a plan now.
4.100 Bore, Small Valve notches and 3.5 Callies Crank. Keeps me under the 6ltr + 2% rule. Anyone know how much can safely be Milled off LS3 Blocks?

IPRAVN

My next problem is Intake Manifold.
Is there anything available that is not to tall and not crazy money?

lil john

Listed that problem on the second post. Modded intake flanges is the cheapest route will set you back a little ..... I just don't get it over 3 grand on head work for valves,rockers.etc. Add in resleeved block. You would come out better just using smaller valves. Can't cheap skate on intake cause the way your going high flowing heads with a resleeved block needs as much air as possible.