Griffith has had a disjointed season to date with few clubs having the numbers for a third grade side.

But on he back of their excellent form in the last month, the Blacks are peaking at the right time of the season.

Last weekend they defeated arch-rivals Waratahs 12-7 to earn their place in the decider, with Griffith's Ashley Gunn saying the side proved they can withstand the inevitable pressure they will be under at times tomorrow.

"They (Waratahs) had about 10 penalties in a row so they had so much ball they eventually scored, but our defence is pretty good and we've got a pretty good forward pack," Gunn said.

"They didn't have much out wide so they were never going to score many long-range tries, they were trying to get kicks to the sideline and then tuck it through rolling mauls, but we negated that pretty well.

"I think we'll get a few young guys back this week so we'll have even more speed on the wing."

Griffith will need all of the younger players it can get its hands on, given they will be playing a team where many of the players are yet to blow out 21 birthday candles.

"But we'll basically play the same side as we did last week, and the last time we played Aggies we should have beaten them," Gunn said.

"They're not a very big side so we're going to play them up the middle bit especially if it's wet, we'll play it up the middle third of the field in a very forwards-orientated game.

"We'll be treating it as a bit of fun, but they've got three grades (in the grand finals), we'll be out to knock them over.

"Thirds for them is only 19 while most of us are closer to 35, but we'll be trying to use our experience."

Ag College, like many teams in Southern Inland, pick and chose the best time to get involved in the contest over the ball at the ruck.

They often tackle the player and then fan out in their defensive line and wait for the next attacking surge, but Gunn said his side will try and open gaps out wide, by using the rolling maul in an attempt to suck in defensive players close to the ball.

Kick off is at Conolly Park at 11.05am.