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Originally Posted by 70KGOLD
I’m no stranger to detonation and walking home. I remember the first time I bolted a set of # 48 heads on my 75 400 engine. It was late Saturday night when I got the car running. I left my driveway sideways leaving black marks for quite a distance. After running a stock 75 400 for years, this was great. But then it started happening. Within 40 min of leaving my garage the temperature hand was pegged out and the death rattle was getting louder and louder. I did make it home that night but not before blowing a head gasket and pretty much toasting my engine. That was several years and head gaskets ago. The #48 heads are now on my 455. I can idle in traffic for hours, and run mid 12 at the drag strip but for some reason my MPH is low around 103.
That’s why I would like to try a new combo using a 400 stroker engine with the e-heads. From what I hear they flow much better than a cast head and that may be my problem, the 48 heads just chokes the 455 out on top end. Also shouldn’t the e-head dissipated heat better therefore allow more compression? I thought a 72 cc head on a 400 would make around 10.5 but you guys are saying 11.5?
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In your opening post you mention '400 stroker'. A 400
stroker with the commonly available 4.25" aftermarket stroker crank is now essentially a 455 engine after you add the bigger stroke, so yes it will be close to 11.5:1.
A 400 using a 3.75" stroke 400 crank is close to 10:1 with the 72cc E-heads. One is a 'true' 400, the other is not even close to being a 400. Two different engines, built off the same 400 block.
Aluminum heads do dissipate heat, but that dissipated heat is power
lost. You
must up the compression (by 1/2 to a full point) and the headflow a bit with aluminum heads just to equal the power of iron heads.
Of course the E-heads are a higher flowing head out of the box than most race-ported iron heads, so you're ahead in that respect.