high fit an old silver top 1994 1.8 in my locost kit car with carbs not had it on the road yet but if i hold the revs high at about 4k it starts to blow alot of blue oil like smoke from exhaust is this because the engine is not under load or just needs a good run or poss something worn ?

How have you got the oil breather system set up? If any of the pipework is blocked it can cause oil to get into the combustion chamber. Does it smoke on first start after being sat for a while or only when you Rev it? If it smokes on start up for a short time it would point to valve stem seals, if only on revving and with no breather system issues it would point to worn rings/bores. How many miles are on the engine?

My old silvertop used to do this. No load revs on the drive. Didn't smoke on the road so I never bothered to investigate. Didn't burn oil either. I suspected it was down to cool engine/no load fueling. Wait and see what it does on the road.