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Mate I pretty much read every thread I could find on gt40 heads and boost, and the common theme was that the timing has to be conservative. A lot more than alloy heads. People keeping timing to a max of 18ish seemed to do fine with levels above 10psi, if they had arp bolts/studs. There is always the odd story of the guys that run big boost on stock head bolts with high timing, but they seem to be the odd ones out.

My timing is at 18 max, and I added arp studs also, using felpro 9333's. 10-12psi, so far so good.
 

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Hey husky65 how is you setup tune? Do you have a boost retard box that pulls timing out , are you using meth spray? How much power are you making also?
 

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Even a cursory search will turn up that after about 10 psi people start to have problems. I think there are a lot of variables. Fuel, timing, whether the head has been surfaced or not, etc... I have read head studs are worthy insurance as are good and proper head gaskets.
 

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I slapped my 2.2 kenne bell on my stock e7 headed engine

And it produced 15psig at 1500rpm with no issues

Of coarse that type of backpressure, really doesn’t make efficient power

So again there is no limit to the amount of boost for e7 heads, dwayne30, maybe think about what you are asking

Maybe ask a different way
 

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I'm putting 11psi through my stock E7 heads, stock 28 year old head gaskets and bolts with about 24-26* timing. The only thing smoking is the tires =-)
 

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Sorry I thought you were talking about gt40p heads, which is what I have. I am using a Haltech ecu with meth. Only made 350rwhp due to some small cast exhaust manifolds I'm using. Power died after 5k.

You can't compare e7 heads and gt40p heads also(if you are talking about the p heads that is). They gt40p heads do not like timing. The is magnified when boost is added. You run high timing with gt40p heads with 8+psi and you will lift the heads.
 

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I ran 10 psig with no issues, when I went to 15 psig the gaskets would blow after about 2 runs at 16 degrees timing. With the gt40 non p's. Water/meth injection should help the situation alot.
 
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