5.9, max safe compression?
EQ heads, sealed power 11cc dished pistons, .020 overbore, stock stroke, can set deck hieght at .050 in the hole with a .028 gasket as is, or deck it some for better quench, if it will tolerate higher compression. With out decking the block, it works out to 9.6/1 compression. 93 octane BP gas is what I can run, average DA is 2000 feet or more, local elevation is 1,000 ft, humidity is usually over 50 percent. Cam is 224 @ .050, 276 @ .006 hydraulic roller, will be in at 106. How much would I dare increase compression? At .050 quench, compression would be. 10.5/1?
Are those EQs iron?
I am a streeter,
Back in in the early 2000s,I ran a Hughes cam similar to that (270/280/110 hi-lift; the 050s were 223/230) under aluminum heads at 10.9Scr. I think the Dcr was around 8.8 @180 psi. I ran it on 87E10 with full-timing,lol. I ran 32 to 36 and on the street, couldn't feel any difference, so mostly I run 32 to 34. I cruized it at 60/62and it idled at 14. I ran the Quench at .044 for the first year, and .034 after that.
I don't think you can run that high a Dcr with iron heads, and for sure not at the current .079 Q.I'm not a builder, but I have heard that running Q between .050 and .080 is bad news
But I can't say for sure as I was still on 87E10. I've never since 1999 run anything but 87E10, in that engine.
Imo, I would get the Q down to between .035 and .045 and do whatever it takes to increase the chamber size to avoid detonation.If that means custom machining on the crowns, that is what I would do. I ran the Q down into the hi 020.s with the 292/509 cam and the Scr at 11.3, and it still burned 87E10 at 34*.I spun the dice at as little as .025,with stock rods and hypers, and won.
Perhaps I have too high an opinion of Q,so be it.
Burning 87 for 17 years/125,000 plus miles, I saved a boat-load of cash.And that car burned up a lot of tires.And it broke a lot of parts.But the engine just kept on rolling,rolling....
But I will tell you my secret, since I'm old and we will likely never meet at the track. It's all in the advance curve.And I am at 960 ft. I ran 14 initial and 34 total. But I ran a kinked curve, that delivered 28* at 2800, and then it slowed down, and the 34 wasn't all in until 3400.
I run a manual trans so I am not married to a particular stall. And I can downshift like lightning; faster than lightning on the upshifts, cuz,my tranny has been custom slick-shifted. So I never lug that engine. Besides, I have a dial-back timing device, that I can adjust up to 7.5 degrees either way, right from the driver's seat.
In my next engine, I'm gonna pump the Dcr up yet more.Maybe I'll get to run 89,lol