thanks for all you replies

yeah to be honnest im only chasing torque.

but i want to make a manifold. no point having this welding skill and not useing it.

ok just acouple more questions

if the exhuast manifold is steam pipe. will the heat expansion be too much to make the intake (out of ally) solid? no fleix pipe

and how far will i get before the stock fuel pump isn't able to flow enough?