We’ve got the answers—Mondays when the Summit Racing tech department tackles your automotive-related conundrums. This week, we’re swapping IROC-Z components into an ’86 Monte Carlo SS.
H.M. • Milton, FL
Q: I’m restoring a 1986 Monte Carlo SS and using a 1988 Camaro IROC-Z as a donor car. I really want to improve the Monte Carlo’s performance and handling by swapping over parts from the IROC-Z. The only issue is that I’m not quite sure what will and won’t transfer between the two. Also, what’s the quickest way to figure out the gear ratio on both cars?
A: The Monte Carlo and Camaro were built on very similar platforms, so you should have no problem swapping the engine and transmission. Both of your cars should be equipped with a 7.625-inch rear end, making the gears interchangeable as well. However, if the Camaro has a 9-bolt rear, then it can’t be used in the Monte Carlo.
The fastest way to figure out your gear ratio is to remove the differential cover, count the teeth on both the ring and the pinion, and then divide the number of ring teeth by the pinion teeth. For example:
41 ring teeth/11 pinion teeth = 3.7272.
That gives us a 3.73:1 gear ratio.