Cork Constitution clubman Simon Zebo returns to the starting line-up, replacing the injured Darren Hudson on the left wing, and Corinthians starlet Eoin Griffin, a try scorer as a replacement in the win over Wales, comes in for Brendan Macken at outside centre.
The Irish Under-20s currently sit top of the table with three wins from their opening four games. They are level on six Championship points with second-placed England, but boast a 17-point lead over the English side in terms of scoring difference.
As his charges gun for a Championship and Triple Crown double, Clarke said: "The players are aware of the consequences of Friday's game and the opportunity as a result of the performances to date.
"However, the approach is to focus on the things which we can control. In simple terms respecting the opposition in preparing for 'another Test match' with the same diligence, concentration and desire to improve individually and collectively, while ensuring rest and enjoyment at the appropriate times.
"The mood in the camp is good and there is a real sense of desire to deliver the required performance in what will be another tough encounter against Scotland."
IRELAND UNDER-20 Team & Replacements (v Scotland U-20, RBS U-20 6 Nations Championship, Dubarry Park, Friday, March 19, kick-off 7.35pm):
15 - Andrew Conway (Blackrock College/Leinster)
14 - Tiernan O'Halloran (Galwegians/Connacht)
13 - Eoin Griffin (Corinthians/Connacht)
12 - Nevin Spence (Ballynahinch/Ulster)
11 - Simon Zebo (Cork Constitution/Munster)
10 - James McKinney (Queen's University/Ulster)
9 - John Cooney (UCD/Leinster)
1 - Jack O'Connell (Lansdowne/Leinster)
3 - Stewart Maguire (Old Belvedere/Leinster)
4 - David O'Callaghan (UCC/Munster)
5 - Ben Marshall (UCD/Leinster)
6 - Rhys Ruddock (UCD/Leinster) (capt)
7 - Dominic Ryan (Lansdowne/Leinster)
8 - Patrick Butler (Shannon/Munster)
16 - Risteard Byrne (UCD/Leinster)
17 - Bryan Cagney (UCC/Munster)
18 - Brian Hayes (Cork Constitution/Munster)
19 - Robin O'Sullivan (Bective Rangers/Leinster)
20 - Michael Heaney (Belfast Harlequins/Ulster)
21 - Gareth Quinn McDonogh (Shannon/Munster)
22 - Brendan Macken (Blackrock/Leinster)