I teach on a modified block and have students for 52/52/80/52 minutes most weeks. It felt like it was a bit of a struggle to complete the course, but it wasn't that bad.
I think the biggest issue was one less day of contact per week. Even with 50 minutes or so per class I often had to start a lesson and then have them finish it for homework. With on less day in a week I lost that opportunity a significant number of times. We also lost a lot of time due to State testing, field trips, etc.
It was the first time I taught the course. As a result, I did not keep pace as well as I should have during the first semester. By the time we got to the Performance Tasks things were too tight for my liking.
It is possible to cut out a lesson here or there to save some time, although I did not resort to that.
Are your students motivated? Can they be depended on to finish up at home? If so, I would have no reservations doing the course with your schedule. Just keep things focused and move everyone towards the finish line!