Your suggestions please, I am jonesing to build.
juvat, he's allready running J heads, a open chambered head @ approx. 72cc. Theres no bigger. He didn't mention that he milled it.
I was also tinking of a thicker gasket. Like a custom Cometic @ .060 though I don't know how thick his gaskets are now. Timing could be an issue as well like you mentioned, but it kills performance off alot!
What head gaket are you running now?
You said 210 cranking pressure, what does that convert to on a static ratio?
All excellent questions, and well received, thanks!. You guys are getting into some stuff that I have never probably paid proper attention to.
You are right, that is the reason I thought I could get by with this, the open chambered J heads. They were only cleaned up in the milling, about .010 to square them. Same with the block, as we knew it was potentially going to be an issue.
I am running the cheap builder Fel Pro head gaskets, almost embarrassed to admit it. To my surprise, I have not blown them with all of the cyl pressure this thing is creating. I have purchased two new sets of Mopar Performance head gaskets, they measure .030.
I used to fight blowing head gaskets on my drag car motor, until I went to those Fel Pros with the stainless ring, but didn't ever bother to measure them.
I do not understand the difference in compression formulas, but I did plug the numbers into a link, someone had posted in another thread. It was around .488 or something like that, my short term memory is fried. :-D
I just know that 210 lbs. with almost no cyl to cyl variation is the highest I have ever measured with any motor, even my 426 Hemi. My 383 race motor, with .130 milled heads was right in that range, but that was 22 years ago.
Do you really think a different head gasket could lower it that much? I guess that makes a lot of sense, it would be like dropping the piston .030 in the hole. Do you have more information on locating those thick gaskets?
**edit** found this article, very interesting.
http://www.hotrod.com/techarticles/engine/hrdp_0603_cometic_cylinder_head_gaskets/photo_04.html
Timing is extremely sensitive on this motor, it wants 38 total, real bad. I run a MP race distributor with no vacuum advance, and the chrome box. In fact, it starts falling flat on its face and won't idle below 30.