No idea what your combo is, but we've been through this. The 2.45 904 was quick in 60', when it hooked. 2 or 3 good runs, and then turning the tires when the track got marginal, was not a recipe for success. Went to a 1.76 2 speed and turned the car into a turd. Made the suspension as aggressive as I could and it still wouldn't move. A 1.96 gear set and the car was mint. 60s came right back to where the 904 had been, but it was not such a slave to the track conditions.

If the SLR is out of whack, all the chassis tuning in the world will not make it as good as it can be. A 4 link gives you a bigger window over ladder bars if you have too much gear. Cubic inches, stroke, suspension type, weight and percentages, what kind of racing you're doing, and a hundred other things enter in to it. There are gear sets available for the 904 but they aren't cheap. Neither are the good Glide gear sets. But a light car (<2500# or so) with enough power to get into the low nines and a short wheelbase will be easier to get right with the 2 speed.