Heads

[Ben3042]

Any one know how much of any improvement i will get if i was to put a 1.2 head onto a 1.4 sr engine?

Cheerz

Ben

[Dicko]

a few bhp, nothing spectacular but worth doing!

[m.d.]

if u can get hold of a die grinder or even a dremel try to match the ports on the head to the ones on the inle/exhaust ports. use a gasket and grind the ports to it. easy to do and will improve airflow. good idea to get it skimmed too, to raise the comression.

[craig green]

1.4 heads were built for economy & smooth sound. The ports are poorly shaped and the combustion chambers are shaped differently. The 1.2 head is more efficient on the 1.4 (1.2 head is useable as they have bigger bores than 1.3/close to 1.4) As for matching the ports, do it on the exhaust side but a little disturbance on the inlet helps a good mixture.
You should gain a few bhp. It'll sound sweeter and the cr will be a touch higher anyways.

[novaexplod]

so wot wud happen if u put a 1.3 sr head on to a 1.2 block?

[craig green]

You cant (very well) The combustion chamber (bore) is smaller on the 1.3 head. The 1.3 uses a longer stroke crank to gain capacity but has smaller bores (pistons) than the 1.2. You can use 1.2 block & pistons with 1.2 head 1.3 crank & con rods to get a 1.4 thats better than the GM version.

[Barn]

what manifold(s) are best to use?