Hi. I'm posting a new thread because I didn't want to hijack another thread that this subject came up on: Gear ratios. I was bragging about my "racing" days, and gear ratios were mentioned. The following is some information that I have learned over the years, and the following opinions on gear choice are my opinions and nothing else. I am no engineer. I've run GTO's over the years with ratio's from 2.56:1 to 4.56:1. Stock early GTO's with stickshift usually came through with 3.55 gears, and aut0 cars had 3.36 gears standard. The 3.55 (4-Series) carrier could accomodate gears from 4.88 or so down to 3.36. The 3 series carriers could accomodate gears from 3.23 down to 2.51. I found that "back in the day", with cheap gas and road noise a fact of life, the 3.55 gears were okay.....the '66 tended to be running about 3200 rpm at 70mph....right in the power band. The speed limit was 55 at the time.Top end was ok. Low end was great. Good "all around" gear, back then. Now, 3200 rpm at 70 is too darn high. Too much noise, too much fuel, and with a big block Pontiac, uneeded. I ran a 3.90 gear in a '65 for a while. That car HATED the hiway. Top end was 107 mph, at redline. It would get there really quick, though. I changed out those 3.90's with a 3.36 gearset (the tallest gearset I could run in my 4 series carrier) back in 1990. Changed the car. Now, it loves 70 mph. It feels just about as strong out of the hole (Still can't hook up....tire smoke central), my fuel economy went way up, and my road noise went way down. I had another '65 with a 3.23 gear and a 4-speed, and the 3.23 is my FAVORITE gear ratio for these cars. It does everything well: accellerate, cruise, and top end. I drove a '65 with a 2.56 gear. GREAT top end, doggy as hell off the line. Too extreme. A friend had a 2.93 gear in his '67. The car would kick down into 2nd gear (turbo 400) at 85-90 mph. We smoked a 427 '65 Corvette on the hiway one day....he was running 4.11's and was done at around 105mph. The '67 would top 140 mph, I'm sure. Another friend had a 4.88 geared, dual quad 455 '66. We broke the wheel studs on the rear wheels getting on the freeway one day. He jumped on it, and there we were. The car would lay rubber when you got on it at 65mph., in 4th gear. Scary. cruising speed was 55 mph. Got about 8mpg at 55! My convertible '67 has the stock, 3.36 gearset. I wish it had a 3.23. It is a little busier at speed than I wish it was. I guess I'm getting old...I like running at 75 mph with minimum road noise and fuel consumption. Today, there's a lot of options with overdrives, lock-up converters, etc. If you want to modify your GTO and add a 700R4 trans, or add a 5 or 6 speed stick, you can run a 3.55 or 4.11 gear and STILL cruise at high speeds. If you're like me, and don't want to cut up your original old Goat, you have to choose what gear ratio best suits YOUR needs. For this guy, it's 3.23's.