Currently rebuilding an L18 and noticed that 2 & 3 exhaust ports are considerably larger than 1 & 4 on the seemingly un modified w53 head. Is this normal or have i got a one off freak. I have never heard it running so am unsure what effect if any this has on the engine. can anybody out there in datto land help me before i attack it with a die grinder?

Can you post a pic, the only weird exhaust ports on L-series heads ive seen have had a steel liner to help burn gasses for emmisions. Do they still have casting marks on the middle two ports?

will take some pics tomorrow. the ports seem untouched there still quite dirty but feel like rough casting still.

sounds about right to me, the middle 2 exhaust ports are a fair bit bigger standard
heres mine

thnks for posting that pic saved me the trouble. If this is the norm how should i go about flowing them up a bit? i am not building anything extreme i was just going to smoothe out the bends a bit. I have lightened the flywheel and knife edged the crank in the hope of a few more rpm. i will probably get the standard cam reground, and have a pair of su's and flat top pistons. can any body tell me if there is any need to even out the exhaust ports.