heads/compression I am unsure of... I didn't have them go through the whole fine tuning aspect honestly. I originally brought the car in to look at my holley 750 because it was stumbling and there was a vacuum leak somewhere. Ultimately they said the carb I had on there was garbage, which I had no doubt it was, because it was very old and worn out. Kenny Bumbera is a carburetor guru and had some new HP Ultras laying around and gave me a great price. He worked very well with my budget, they talked to me about everything they were going to do or were wanting to do and waited for my approval. Just go over there and talk to them and they will probably show you around the shop too. It's basically a classic car performance shop. I will be taking my car there for now on because of how well they treated me and my car and providing good knowledge and info.
His policy with the carbs is, if you don't like it for whatever reason he will buy it back from you or put the carb as payment toward something else. If you decided to rebuild your engine with higher performance parts with a carb you purchased from him he will use the money you spent with him and credit it toward a carb more suitable for the rebuilt engine. He also provides a couple years of warranty too.