Hi all,
Thank you so much for your comments and advice. I certainly thought that £1k a valve seemed excessive so glad you all agree. JohnD is correct in his assessment, I’m not experienced nor confident with working with the engine hence seeking both your combined advice as well as a specialist. I have since contacted Chic Doig who estimated between £2-3k for a full restoration of the engine.
I have had the carbs reset and the tappers have all been checked a few months ago. Also, I’m not sure if it would be an electrical fault or anything to do with the plugs as I had an electronic ignition fitted as well as the leads and plugs all being changed a matter of months ago.
I will certainly buy a compression test kit and give that a go.
I have a few audio clips of the engine when it is misfiring so will see if I’m able to upload them for you to see what your thoughts are.
I am more tempted to have a full rebuild done as I plan to keep the car for a long time and would like to use it as much as I can. And so having the engine rebuilt would give me greater piece of mind. I live a few miles from the NC500 and would love to use my GT6 driving round it. The car is wonderful to drive and always puts a smile on my face but right now I always have a little bit of dread when I take it out, wondering if or when it will begin to go wrong.
Thanks, Andrew