Hi Red: Costello's playing dimensions by the encyclopedia: 6-0, 228.
I think he probably weighed more than that when he was with the Giants. As I recall he had a bit of a gut.
He had four picks in 67, which was second on the team to Spider's 5. I remember a good form tackler who led with his pads to increase the hitting surface when he attempted to drop the ball carrier. Nimble in coverage as the interceptions would attest. But not a guy who in that point in his career was going to cover somebody 25 yards down the field like Huff did.
He was probably best described as a tough, resilient bandaid covering a gaping gash. Despite his considerable efforts, the 67 team gave up the following point totals: Dallas-38, Washington-38,, Green Bay -48, Cleveland -34, Chicago-34 & Detroit-30.
This was a high scoring era so you have to curve the TPA. For example, the Cowboys were 9-5 that year but they gave up 24, 35,21,21, 27,21,23& 24 on their fourteen game sked. The Skins led by Otto Graham gave up 30 or more 5 times with a high-water mark of 42 against the Browns.
Consider the corp of linebackers he played with: Mike Ciccollela, Bill Swain, Ed Weisacosky, Ken Avery and Dick Kotite (! yes that Kotite. I only remember Wagner's finest as a tight end) You could make the case that Ken Avery was a pretty good football player, a guy who later played for the expansion Bengals. Everybody else, you throw back in the water.
1968: No picks, but remember he's 36 at that point. Know many 36 year old linebackers? The defense actually kept the scores down better in this season. Only Cleveland exceeded 30. They did so in a big way when the beat the Giants 45-10 on the third to last game of the year. That one was in Cleveland. Henry Davis appeared on the scene that season. Remember him? He would later make some noise with the Steelers in the embryonic stages of their burgeoning dynasty, along with another ex-Giant--John "Frenchy" Fuqua.
Actually I liked the 68 backers much better. They had Tommy Crutcher, who was a pretty good linebacker who got lost behind Robinson-Nitschke-Caffey, and the young Fred Carr. Dave Robinson and Bobby Bell were actually the protypes of the size-speed-range variety at the OLB position. It didn't start with LT, folks.
Costello is remembered fondly by Giants fans of that era as a reliable, durable, steadying force on what was actually a pretty gruesome defense.
He played his best ball with the Browns--no question--but he saved a little for the Giants.