If you are looking to spend a little less money you can run these and they work with stock pistons:
185cc SBF Enforcer Cylinder Head - Stock Piston Small Valve
Cylinder Head Specialistswww.airflowresearch.com
Flow rates on the GT40’s can be seen here:
I’m not boost savvy but maybe Noobz or rednotch would have some cylinder head opinion based on your build if you want to reach out.
I've read some batches of the Cometic gaskets had a design issue and were leaking. Have you seen this? https://www.google.com/amp/s/stangnet.com/mustang-forums/threads/cometic-head-gaskets-leaking.726273/?amp=1The current GT 40’s have already been shaved .012” and it has Cometic gaskets and ARP studs. They’ve been re-torqued. Last time the heads were off the block was also freshened up including deck shaved .003”. I’m at the end of the rope with these heads. Their deck is lifting. They’re too weak for boost.
Thanks for pointing that out to me. I definitely check it out.I've read some batches of the Cometic gaskets had a design issue and were leaking. Have you seen this? https://www.google.com/amp/s/stangnet.com/mustang-forums/threads/cometic-head-gaskets-leaking.726273/?amp=1
No personal experience or opinion, just remembered reading it. If you Google "Cometic head gaskets leak" there sure seems to be a lot of content. Maybe just try a different brand?
Yes, you can get away with not pulling timing around 5 or 6, but with iron heads you are on the bleeding edge depending on season and temps. Aluminum heads shed heat better so less risk. You can lose up to 2 deg with hot IATs factory tune, when I started making 6psi on e7 heads I had some pinging, I knew a new ECU was in the plans but picked up a BTM cheap so went that way. I'm pulling about 1.5deg/psi but not starting till 4.5lbs so short pulls have full timing. I'm leaving ponies on the table but I'm just tuning in the driveway with 90s tech so staying conservative. You might be fine depending on fueling and under hood temps. The line of fine/not fine can be catastrophic tho.I might be a bigger dipthan I think I am.
I have all the Moates stuff to DIY tune but I haven't learned nor utilized it. I should really do that before I buy new heads. Even if it doesn't make a difference now, I will still need to do it with the new head combo.
The entry level Vortech kit doesn't say you need to pull timing. However, I’m beyond the entry level by a notch at least. Maybe a proper tune with some pulled timing will let the engine tolerate 7psi without puking coolant.
I repeat, I’m a stubborn dipsometimes
Hmmm, then too much timing cant be the cause of puking coolant right?Yes, that's basically pulling 2 degrees from bas map assumed of 10 so you should be good there. @7
Correct. Timing impacts the onset of spark and the efficiency of the downward piston stroke (power stroke). Burn time across the inside of the piston and the rise in pressure, you want to ideally fire off the explosion just a bit before the optimal time so that the piston rounds TDC and has full impact of cylinder pressure when it's on its way down, that is why if you are too soon, you blow a rod through the sidewall as all that explosion has nowhere to go if the rod is not on the downward slide of the crank rotation. That's why heat changes timing as it increases burn speed or could cause predestination, also why e85 and meth change timing (allow more) as slows burn speed allowing for more timing.Hmmm, then too much timing cant be the cause of puking coolant right?
You have to change oil, water contaminated oil will greatly reduce lubrication and cut open the oil filter just to take a peek for sparkles. Also, if you end up burning antifreeze it can leave some nasty deposits that are more gummy than hard and crusty. They are really hard to clean off a pistol during a head swap....I mean I've heardThanks for that detailed explanation. Ive pretty much run the gauntlet with this thing. I think its the heads lifting. Im back to NA with it already and its perfectly fine. Holds the hot coolant and pressurizes and holds. No leaks or other loss of coolant.
Just going to run NA until I bite the bullet on AFR heads. I plan to tune it with Moates Quarterhorse and put the FMU back on the shelf. I might start playing with the QH now while running NA and get familiar with datalogs, on the fly changes and whatnot.
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