Hey there, I'm new to this forum so still trying to figure things out.

I'm in the middle of a rebuild/build (66mm crank, 96mm pistons, cam, dual webber 44 IDF's), i have heard the major downfall of 1.7 heads, besides less then optimum valve sizes, is the small intake ports. I have set of good 1.7 heads with sodium filled exhaust valves and don't really have the funds for new 2.0 ones. (still have to get them fly cut for larger cylinders)
Has anyone tried porting these by hand, without a mill? I have heard of a lot of Chevy guys taking a dremel tool to their heads and successfully improving ports. Seems a bit risky but maybe someone has figured out solid way to do it. I'm also still unclear whether polishing intake ports is a good idea. Seems as though some say the rough walls help with atomization of fuel, but others say smoother is better for flow.

I'm also wondering if i can expect to hit 100 hp with the small 66mm crankshaft. i may increase compression to somewhere in the 8.3 range when i fly cut the heads, and with a good cam and stiffer valve springs it should rev well.

Thanks,
Devon

Find someone or a book that details what the port shape should be for optimum performance. Just hogging material out and enlarging them is not the full answer and can actually harm flow if not done correctly.

You have to know how much material can be safely removed before you break out of the casting and create holes. When we did it, we cut a head thru the ports to determine the amount of material that could be removed safely.

Using a rotary file is a very long and tedious task to get it correct.

Work on Chevy heads has been well documented over the years, but their ports are not the same. Don't know about VW.

Last I remember was leave the intake rough and polish the exhaust ports (that's the way we did it).

Probably the best you can do easily is port match the intake / exhaust manifolds so there is no step between the manifolds and ports.

You have a lot of reading / conversing to do before grinding anything if you want good results.