Using a stock bottom end (no releifs) and heads milled to 67cc's, what is the biggest cam that would fit without notching pistons? Assume stock valves and a .033 gasket.

How much has to be milled off a L92 to get it to 67cc chambers?

 

The rule of thumb is .006 for 1cc so with that said you would need to mill about .018 off of the head. They are 69.8cc from the factory.

 

.040 mill got me to 63.8cc

 

.030 off mine got them to 64.8

 

Anyone wanna take a shot as to what size cam fits with a .018 mill and .033 gaskets? 232 xer?

 

I will, you can do the math, but here it is. Baby 231/235 LSK 110+0, .030 mill, .051 gasket, -9cc dish. You don't mention LSA.

 

-9cc gives quite a bit of extra room. On a flat top piston without reliefs ( which was what I was asking) , I guess I need to know the L92 stock head valve drop. Telling me what you fit with -9cc dish piston and not specifying what clearance you had with your baby cam doesnt give much info. On a 6 liter a HUGE(joke but you broght it up) 231 110lsa would not fit with 243 heads milled enough to give the 8.7 dcr I am looking for. It would require notching the psitons. A 232 112LSA xer requires notching with .040 gaskets and stcok 243's. I doubt the huge valve in these L92's would have a better clearance but I dont know.

I know after these heads installed I/we will have a direct comparrison to ETP 215's, and 243's with the same DCR.

I wanted to test this myself to get real world findings for these heads with no secret cam specs, compression excuses, or BS size cams. My findings are solely to get to the end of the 6 liter question; not how they are with strokers. -------Will the proper/decent dcr get rid of the low end TQ loss.--------

I would think you would be interested.

 

you don't say if your pistons are in the hole or out and how much. Have to know that to give intelligent answer. On my mock ups the intake has a lot less valve drop that we are used to with other ls heads.

 

LS2-stock. I have yet to see a stock LS engine with pistons not out of the hole but mine are .008 out as was my last one and the forged 348 I had after it. So given that as your needed info, what would the biggest cam that fits be? A 232 112LSA with a .033 gasket and .025 milled would be out then?

 

The reason I specify that size is because it is essentially the one used in the GM performance mag test which lost a bit of low end. The corrected DCR should make up the difference.

 

Where are you getting a .033 gasket.

 

.030 of the factory heads. CNC'd heads were milled done to 68cc but they started a little larger than stock after the chamber was worked. I'm running an .040 Cometic gasket.

 

www.cometic.com

They stock .033, .040, .045, .051. They used to stock .027 also but now it is custom order only.

 

What cam size? What was your measured clearance with your cam?

 

My first cam is bigger as far as overlap goes and had more lift. I'm running 2cc pistons so there are some reliefs. I really don't know how that would relate to stock pistons.