I went to see a 66 convertible tonight and the seller told me it had an A code engine rated at 271hp. I knew the K code was rated at 271 but had never heard of an A code with that rating. Everything I have read rated the A code at 225hp. He proceeded to tell me that it had a factory option installed weiand intake plus a beefed up carb. I'm not an expert but this sounds a bit fishy - is this for real and if so, is this rare ???