Cooling Difference in Aluminum heads?

[WOW,, dude that's a lot of info to digest,,,THANKS,,,I'll work on that.
More info on my unit,, 5 speed close ratio stick, 2.66 first, .68 5th, 3.23 rear, intake closes @ 37 abc, my math at Wallace Racing gives me DCR of 9.41 with a 10.1 CR. Just did United Engine & Machine calculator and I got 8.738 DCR, base timing 10*, idle timing 22*. Engine starts at 10 and computer adds 12* for 22* after start, dizzy is locked out.
since I posted I bumped the timing up to these figures and it seems to like it. Even at idle at full temp 190+ the tail pipes are dripping a lot of water, running much cleaner. Driving in traffic I see 213*. Yes your info is helping with a direction ,,thanks.


QUOTE="AJ/FormS, post: 1971720186, member: 33537"]Are you sure about the 9.35 DCR?
That does not compute with a 10.0 Scr
I'm guessing that's a typo and the Dcr is really 8.35?
I grossed your 222@050 up to 262/110 advertised and ran the numbers with 10.0 Scr, and I get 8.38@170 psi; so I'm guessing 8.35 is correct.
Ok having got that outta the way, I ran a cam like that in my 367 for two years, with aluminum heads. I loved that cam. In my 367 it made monster torque and I was able to squeeze 32mpgs out of it, cruising with the equivalent of a 1.97rear gear. Yeah so that cam was for me a perfect street cam. It power-peaked at about 5200 for me.Because it was down on power compared to a much bigger cam, I ran it with an A833OD and a GVOD behind that; so my splits were really tight. This allowed the engine to stay on the pipe from-IDK maybe idle to 110 mph,lol.
Ok I tell you this cuz the chassis loading was very light, the engine never had to pull hard in the detonation zone from stall to about 3600rpm. This is key; the lighter the load, the easier it is to stay outta detonation.
Furthermore I ran at a minimum coolant temp of 205*F. This makes it easier to find detonation, than say at 180 or 165.
Further more I run a 3.58 stroke,vs your 3.31. My pistons dwell at the top longer than yours, again inviting detonation.
I'm telling you these things cuz, you need to know that, and so my engine will have different timing requirements from idle to 3600ish, than your 340.

So now,with EFI, the door is wide open, on account of there is no T-port sync to deal with. The power timing will be the same or very similar to mine as all hi-compression SBMs run about the same; namely 36* with iron heads and 32/34 with aluminum and tight Q,like yours. I felt no difference between 36 and 32, so most of the time I run 32* . So that is step 1.
Idle timing with Efi can be whatever you want it to be from as little as 12* with that cam (mine ran 12*), to as much as perhaps 22* or wherever the starter complains about it. That is step 2.
If you have a stick car with hiway gears, I suggest starting on the low end of the scale. If 3.73s or better, then on the hi-side. With 3.55s or 3.23s I suggest 16*.
If you have an automatic, it goes according to the stall-speed; the higher it is, the more timing you can run, cuz the engine is only lightly loaded and spends waaay less time in the detonation zone,below 3600.And again 4.30s will drive the revs up much faster than 2.76s,lol.

So a typical combo used with a 222 cam, will be an auto with 3.23s and a 2400TC.And I'll assume it to be in a 3400# chassis. With this,I expect it to idle at 650 in gear/750in N/P. I would start out at maybe 16* at idle. I would then bring timing in starting at about 1000 rpm, at the rate of .75*/100rpm until you hit about 29.5* total@2800rpm. From there I would slow it down to .6*/100 until all 32/34 are in, somewhere after 3400rpm. This curve will probably let you burn 87E10 without detonation.

But if you're ok burning slow-gas 91,
then you can start off sooner at a higher number and finish sooner also at a higher number. In this case you can start at say 900rpm with 18/20, and slam 16 more in by 3000, for a total of 32/34, with a straight "curve"of .75* per 100rpm.
So that takes care of the power timing

Now as to VA, or equivalent. I found my 367 power curve loved plenty of timing at PT and higher vacuum readings. For instance at 2800rpm, the car was doing 33mph in second (3.55s)and the power timing,as mentioned was 28*. I installed a 22* VA can and so the total at 2800 was 50* and the engine liked that. Then at 65mph in double OD the rpms were 1600ish. The power timing here was just about 17* with 22 more in the can for a total of 39*. I didn't think this was enough. I had earlier installed a dial-back timing device that was able to change the timing from the driver's seat ,up to 15 degrees. So I began experimenting with more timing. The potential total now was 39+15=54*. I had installed the DB device with the adjuster knob in the center allowing changes of 7.5* advance and 7.5* retard. Well she liked all 7.5*,for a total of 46.5. Running this combo up to 75/80 mph, the total cruise timing became about 51/53. Then I leaned out the low-speed circuit. And leaned it out some more, and eventually that combo pulled 32 mpgUS at 75 mpg/1900 rpm.
So, what I'm saying is with a stick-car, a carb and a common dizzy, it is my opinion that starting with less is more. 14* of base timing and 20 in the dizzy and 22 in the VA and the DB gizmo, got me to where the engine wanted to be. And it burned 87E10 with 10.9Scr/8.9Dcr. The slight loss of torque at the lower rpms was never noticed (remember it's a stick car with a 10.97 starter gear), and mostly it has enough power to spin 295s to 50/60 mph,anyway.
If I would'a had an A/T I would just slammed 4* more into her, topping out at 34@2800 and called it done.

PS if you have a stick, driving at very low speeds can become an exercise in clutch-slipping. If you retard the timing from about 75 rpm below the normal idle rpm, and set the rate of decay at about 12*/100rpm, it takes most of the jumpiness out. My 367 will pull itself at 550rpm with just 6* of advance. With 3.55s and a 3.09 low gear, this works out to about 4mph, a fast walk.That's with a fat 750DP, and a 230/110 cam.
BTW, the DB device is an awesome tuning aid.

I'm not sure I've been any help, just remember; the lighter the loading, the less likely the engine is to detonate, and every combo is different. [/QUOTE]