Dong Yi fired a 6-under 65 and is alone in fourth place at minus-4. Adam Spiers and Scott Gibson both shot matching rounds of 3-under 68 and are knotted in fifth place at 3-under-par 139.
On Thursday, high winds allowed only five players to break par. Conditions were much better on Friday and scores reflected it.
Grob's biggest shot of the day came at the 230-yard, par-3 ninth. He converted a 12-foot par putt at the hole, but the 41-year-old has his eye on something else.
If he finishes in the top-4, he would vault past Jim Rutledge into first on the Canadian Tour's all-time earning list.
'I'm not sure what to think,' admitted Grob. 'I almost feel like Crash Davis chasing that home-run record in 'Bull Durham'. But I know Jim very well and it would be special.'
Williamson, who along with Grob and Mike Sabo shared the first-round lead, joined the leaders with an 18-foot birdie putt at his final hole.
'When I got out here today and saw the wind was down, I knew two-under wouldn't hold very long,' said Williamson, referring to his score that shared the lead on Thursday. 'I've got to get some more confidence playing on the weekend, so this will be a good test.'
DeLeon had the lead to himself at 6-under par, but a three-putt bogey at his last, No. 9 at Pine Ridge Golf and Country Club, cost him the sole possession of first.
'I said to myself to get aggressive on the first putt and I still left it 10 feet short,' said DeLeon, who broke his wrist last year. 'But I've been playing very well. It should be a lot of fun over the next two days.'
Stephen Woodard is alone in seventh place after a 3-under 68. He finished 36 holes at 2-under-par 140.
Brien Davis (69), Derek Gillespie (67), Berry Henson (67), Pan Singhaseni (64), Todd Tanner (67) and Jeff Wood (68) are knotted in eighth place at minus-1.
The 36-hole cut fell at 4-over-par 146 and 65 players made it to the weekend.