Help with adjusting cooking times for meat/weight

So I'm thinking of making this Pork Sirloin Roast tonight and settled on this recipe...

I have a 5lb roast, though, not 3. I was wondering how much additional time I should allow for cooking since the original is done at a low 225F and 2lbs is a significant increase in weight?

Thanks all!

I couldn't begin to tell you,  I haven't gone by time in a while.  I know it's not as simple as adding 40% to the cook time.  

The best advice is going to be grab a probe thermometer and follow the instructions in there.  I saw one for $14 at Walmart yesterday so it shouldn't break the bank.  It's one of those top 5 tools that will instantly make your food better and more consistent so please, please get one.  I guarantee it will be worth it.

I have one of those exact ones from Wal Mart...I'm a noob so I didn't realize I could put that wire/probe in the oven the whole time. The jacketing on the wire just doesn't seem heat/fire proof.

 It'll be fine as long as you don't use it with the oven going full blast.  I actually blew a probe out when I cranked up the oven to 500 to brown a turkey and didn't even think about the probe.  But anything up to like 400 you'll be fine.  Just put the probe in horizontally so the tip is as close to center of the roast as you can guess, then run the wire out the oven and close the door.  Make sure it doesn't have a kink and you don't pull it super taut when you're shutting the door and you'll be golden.  You already have the makings of a great roast.  

Now the only other thing I can think of is that you don't have to incinerate pork anymore.  You can actually cook it to medium so it's still juicy.  I think 165-170 is the "official" temperature for pork loins n' stuff.  Still, that 145 in the recipe might be a little on the low side though.  I set the probe to pull at 150 and let carryover bring it to 155 on the counter.  


Thanks for the time and input!

I decided to put it off tomorrow since I'll have more time. Here's hoping for a successful meal!

I'm really a noob btw, this will be my first time doing a "deglaze" and making a sauce.

5lbs @ 225 is gonna be like 7 hours

kinda weird but the temp is at 146 now and its been 2.5 hours at most.

I'm gonna go get some readings in different spots.

Ok, its actually at about 130 degrees in the coolest spot I could find.