Bourbon Barrel Porter Question

Good Morning! Quick question about the recipe I’m working on. NB’s BBP is my 4th home brew – I brewed it Saturday night and pitched the yeast around 10:00 PM with an IG of 170 @ 66 F. The room I have the fermenter in sits at a pretty consistent 70 F. When I checked on it around 9:00 AM yesterday, the blow-off valve I set up (per the recommendation of many reviewer of the recipe) was at a constant bubble (large bubble every 1/2-1 sec). This continued throughout the day yesterday and was still going strong last night around 11:00 PM. I just checked on it this morning and there is no activity coming out of the blow-off. I watched it for about 5 min with no gas release.

This recipe comes with a lot of firsts for me – blow-off valve, dry yeast, porter. My first three recipes (IPA, Saison, Alagash Replica) used the normal airlock and had 4-5 days of activity that very gradually slowed down, so this situation seemed a little out of character for me. Should I be concerned? If this is normal, can someone help me out a little bit with understanding why the difference?

Thanks in advance for the insight!

These are my notes I hope they help. Sorry for the short response, this is the third time I have typed this and hopefully doesnt get deleted this time! I initially planned on a 2 week primary and 4 week secondary.
This is what the new plan is:
3 weeks primary
4 weeks secondary
start soaking oak and 3 madagascar vanilla beans in bourbon at the time of transfer to secondary.
transfer entire bourbon soaked mix with bourbon to secondary at the 2 week secondary mark.

Brewed 2-4-14
Yeast pitched @ 9:45 p.m. 68F
O.G. 1.065-1.066 (adjusted for temp)
Initial fermentation done in the basement.
2-5-14 8:00 a.m. 62-64
F, 1/2" krausen
2-5-14 7:00 p.m. 58-60F, active fermentation with blowoff foaming.
2-6-14 1:00 a.m. 60-62
F, heavy active fermentation.
2-7-14 9:00 a.m. 58-60*F, krausen receeded, moved to closet up stairs and installed airlock.

Temp has been steady @ 64-66*F since 2-8-14.

With the ambient temp at 70*, it probably fermented at 75*+ which is a tad bit high. That could explain the short active phase. It might also lead to some off flavors. Do a search for swamp cooler to help maintain a lower ferm temp in the future. I’ve used that with pretty good success in maintaining a ferm temp in the mid 60’s. Frozen water bottles can help lower the temp in the swamp cooler if the ambient is too high.