Alright, here's the deal.

I've got a set of heads a good friend is working on (owns his own head porting business) That I want to have milled to raise the compression of the heads/cam setup i'm working on. But, I need to know if anyone can give me insight on to if i'm going to run into PtoV issues with this cam.

The cam is a XER 228/232 @ .050, 110 LSA +2

(I know this cam fits with stock heads just fine)

I want to mill the heads 5cc's to get 61cc heads with a .040 gasket, the heads also have 2.02 intake and 1.57 exhaust valves.

This will give me: SCR of 11.13 and DCR of 8.73, perfect for my street setup.

Questions:

1. Will the Cometic gasket I want to use work? I see it states stock bore, but it shows 3.91 whereas "stock" is 3.898, i'm assuming its not enough difference to matter is it?
2. Will the cam fit with 5cc's gone out of the heads and a thinner gasket with this duration and 110 LSA?

I would like to have an idea on this BEFORE I mill the heads and possibly run into trouble.

Any help would be AWESOME

 

TTT..

Anyone? Not sure why this was moved out of the Advanced section..

 

Thats cuttin in close, Your going to have to clay it to be sure. I think your going to have to fly cut to be on the safe side

 

The problem is, I want to figure this out BEFORE I mill the heads, lol.. any experience that leads you to believe it will be close?

I don't really want to mess with flycutting, if it comes to that i'll just wait and build another motor with good pistons.

Thanks for you input.

 

I can almost guarantee that you'll have to flycut if that 61cc chamber is a 243, 241, or 853 casting with that duration cam, aftermarket valves and a .040 gasket. Aftermarket valves eat up a lot of PTV clearance not only becaues of the diameter, but b/c of the margin.

You're def. on the right track w/ that static and dynamic compression though. If you keep stock valves, and lower the duration to about 224/228ish, you'd be closer to spec w/o dramatically reducing performance.

 

I'm sure I don't have to tell you that you HAVE TO measure when you start getting close.

https://ls1tech.com/forums/generation-iii-internal-engine/515456-ptv-measurement.html

 

Thanks for the info!

Of course I was going to check, but the only problem is wasting the money on the other stuff just to figure out if it is going to work or not. I might be able to mock up the stuff on a stock 6.0 short block (I have the cam already) I have laying around and use the heads before they are milled, that way i'll know how much room I have to work with.

I might still flycut depending on how close it is, just because I really wanna see what this setup will do..haha