[Barry_R]

I assembled and dyno'd the engine. It broke in nicely, ran quite well, made good power and had no outward symptoms of any distress - seemed like a good piece.

The carbs were prefessionally replated and reconditioned originals. The heads have new bronze guides and viton seals. The intake gaskets are either steel lined or BTs - can't remember which but definitely not the unreinforced 1247s.

Really sounds like a fuel/carb related issue - especially the hard start. Very possible to get some trash into a needle/seat with a new build - lots of fresh hoses and connections. Or we could have gotten a funky gasket or float.

I see a lot of problems with current pump gas on heat soak. Fuel boiling points have changed a lot since newer cars are all running fuel injection with no open reservoir of gas (float bowl) and running pressures of 50+psi instead of the 6 or 7 we run. Local gas formulations change a bunch now too, both by region and by season - with varied amounts of alcohol in the mix. I have one customer who would pick up his car running great, drive home in Michigan's Upper Pennisula (+/-6 hours) and say the car always started running like crap halfway there with hard starts and roughness and dieseling. Turned out he would always fill up at the same station in Williamsville on the way - he brought 10 gallons of that swill down to the shop and we tuned around it - problems cured.