QUOTE(914sgofast2 @ Nov 5 2020, 12:15 PM)
All Type 4 heads will bolt to the short block, but 1.7 heads need to be flycut to fit over the 2.0 cylinder barrels. The 2.0 bus heads have the same size valves as the Porsche 1.7 heads, so using them would reduce the ultimate air flow at higher rpms. You should be aware that 2.0 bus heads have two different exhaust port types. The earlier 2.0 bus heads use the oval copper exhaust gaskets like all Porsche 914’s use. The later 2.0 bus heads use rectangular port composite metal exhaust gaskets that will not work with the Porsche 914 exhaust systems used on 1.7s , 1.8s, and 2.0s. You did not state what type of exhaust ports your 2.0 bus heads have.
The 1.8 heads will fit over the 2.0 cylinder barrels without any modifications. They have the exhaust ports that are compatible with the 914 exhaust system.
The ultimate question is whether you simply want a quick and dirty fix to get a running engine for your car or a longer term fix. If you have 2.0 bus heads with the oval exhaust ports, they will bolt right up and you can use them to make a running engine that will allow you to move your 914 around. If you want a longer term running engine, then get the 1.8 liter heads fixed and use them to build a higher performance engine. If I remember correctly, the rebuilt Porsche heads sold by vendors such as Auto Atlanta are based on the 1.8 liter heads since they have bigger valves than the 1.7 liter heads but are not as prone to dropping valve seats as the 2.0 Porsche 914 heads.
So does anybody know what a good perf mod to the 1.8 head would be?
what size valves? would that be the only mod? the 2.0 914 heads are next to impossible, and I feel I am done looking for them, I don't care anymore. I am good with modding a 1.8 head. running that for awhile, enjoy it.
and I will sell off the 2.0 bus heads. I bought the engine with the "heads", and when I saw them I was bummed..
all good. I am cool with 1.8 heads.