The camshaft is the brain of the engine, different engines have different needs. The head ports and combustion chamber design, rod/stroke ratio, type of intake manifold, the weight of the car, the cubic inch size of the engine, transmission type, rear end ratio, what is the intended use, racing, touring or just local short trips? There is no perfect camshaft either, a bigger cam comes at a cost, lower MPG, rough idle, less manifold vacuum for power brakes, poor cold start ups, less low end torque and accelerated valve train wear. The factory Nailhead cams were more aggressive than most other engines. The stock Buick cams are still better than what many cam grinders offer as MILD cams. Some cam's like the THUMPR have lobe spacing way too close (107 LSA) to what the Nailhead likes, too much overlap, you can smell the unburned fuel!. When we pick a cam for a customer we ask the questions needed to make the correct choice. FYI LSA is Lobe Separation Angle. Here are some factory Buick cam spec's compared at the industry standard at .050 lift, advertised duration is useless to compare one grind to another. Duration at say, .002 means nothing because before the valves are opened .050 there is no flow that is measurable. (FYI the 53-56 cams and the 57-66 cams will not swap, different cam bearing sizes) The 1956 factory Export solid lifter cam. 212 duration @ .050, valve lift .420 lift and 111 LSA .015 valve lash Late 401 factory cam and 66 425 207 duration @ .050, valve lift .431 and 114 LSA 1963-1965 425 factory cam 208 @.050 on the intake, 213 on the exhaust, about the same lift as the 401 but 109 LSA This last cam is called a DUAL PATTERN because intake and exhaust lobes differ. These spec's give you some idea when you compare aftermarket camshafts. You can run a tighter LSA (smaller number) on a smaller cam profile. Roller cams, I am not sold on them yet for the Nailhead, I think on a street engine it is not worth cost. More Lift is something that doesn't make the engine idle rough or loose low end torque so we like more lift but how much will depend on piston clearance, valve springs and if you are using roller rockers or not. Lastly, EVERY PERFORMANCE CAM needs to be checked with a degree wheel, dialed in. We have had cams from all the major manufactures and not a single grinder has a perfect record. A cam just 2 or 3 degrees off can make a difference and we have seen them as far off as 17 degrees!! We highly recommend our roller timing chain with extra key ways when ever a performance cam is used. Two lifters were used (not counting the factory Export solid lifter), the 1953-55 and the 1956-66. The 1953-55 camshafts were steel and the lifters had a deeper push rod socket so they could not be mixed up were 56 and later cast iron cams. I have found that the early lifter will work on either steel or iron cam but best use the early lifters on the early cam.. This means the correct push rods are needed for each type lifter, the 53-55 is longer than the 56. Many parts suppliers are ignorant to this. Also as the engines got larger, the blocks grew taller and same with the push rods. 364 and then the longest was used in the 401-425. Common mistakes.. The camshaft snout MUST protrude out of the cam sprocket slightly for the fuel pump eccentric, sprocket and camshaft to bolt together correctly. Our oil galley kits come with the sometimes missing snap ring that installs behind the rear cam bearing, this will keep you from knocking out the large cam plug while installing the cam sprocket that sometimes is removed and installed many times when dialing a hi-performance cam.