Heat soak on the inlet side is allways going to rob you of power.

There are some very natty silicone inlet manifold gaskets that reduce heat transfer from the head into the inlet avaliable fromt he US.. these may well help the cause.. it is often the little things u do whilst tuning that have the most benefit..

My exhaust manifold will be ceramic coated to reduce under bonnet temps. It also has the benefit of keeping the heat in the exhaust gas and thus keeping the gas speed up, enhancing the scavanging effect of the exhaust pulse..

Cheers,

Rich.