I've said it before, and I still stand by it.  Contact your preferred cam manufacturer, tell him what you have and what you expect from your cam, and let him tell you what you need.  He'll steer you right, he wants you to be happy with his cam.  By the way, if your engine is a '57 and has the original rockers, they are the preferred 1.54 ratio.

Reducing the lobe centerline increases peak torque at the expense of making the torque range itself narrower.  That’s the short explanation.  And J. Mummert is correct in that open headers will prefer a reduced lobe centerline as scavenging is better taken advantage of in that instance.  But I’ve installed camshafts with as low as 102° lobe centers in specific applications so don’t believe for a minute that 108° is the lower end of the spectrum.  But both the advertised and the 0.050” durations as well as the lift also play into the mix and especially as the compression ratio is toyed with.  As I’ve said before, each ‘built’ combination is slightly different thereby requiring different attributes for the camshaft.

The E4 gets aways with the 108° lobe centers by lieu of the short duration and lift.  It still maintains a good manifold vacuum and has a nice rumble or exhaust note due to the reduction in lobe centers.  As an FYI, the OHV or LYB engines for the trucks (317, 302, 332) had shortened lobe centers with a 1963 model 332 cam being ground on 107° lobe centers.  Rock steady idle and extremely torquey.  Not sure if the engineers were trying to compensate for the spacing between the valves in the combustion chamber or if they simply wanted the enhanced torque characteristics that come with reducing the lobe centerline on the camshaft.  But that OHV cam definitely works and gets decent fuel mileage when installed at 102° intake lobe centerline.

And Hoosier has said it before and I’ll reinforce it, “heed the advice of the cam manufacturer” as they deal with this day in and day out and definitely want you to be happy.