I am adding a Stipe 280 cam to my car and after reading some of the stuff on the forum I have a couple of questions reguarding the cyl. head:
1. How do you tell a low head from a high head?
2. what is the stock thickness for each and where is it measured?
3. As I am adding the Stipe 280 cam what would be the best amount to remove from the to increase performance?
As always thanks in advance for your help, Steve
These two pictures will show you the easiest comparison between a low and high cylinder head
The low head is on the top, high on the bottom.
I was able to take .100 off of my stock high cylinder head. Some folks have been able to take off as much as .125 - it mostly depends on whether or not the head has been milled in the past. There's a way of knowing this, but it slips my mind at present....
2nd picture (courtesy of John Sizemore):
The one with bolts is a low head.
Also, read this thread:
I have an aluminum head that I removed to reduce the exhaust smoke and oil use. This one had 95 psi compression on two cylinders and 65 psi compression on two cylinders. The 65 psi suggested a leak between two cylinders, but I'm not sure if 95 was normal or high. I'm also not sure who made the head. There is Made in U.S.A. on it and also VTH-1000H and 20-27 near the back driver's side.
If you have a low head (stock) you do need to know how far down the spark plugs go to seat before milling anything. If you are running standard alum. pistons this may not be an issue. If you are running domed pistons you may strike the head on at speed rotation. Most heads have been milled in the past 80-90 years at some point to level the decking. You really don't want to ruin a solid engine rebuild by not getting the tolerance / variance down pat