2021, 2022 Pure Stock Drags

great video! your amx runs extremely  well....and is a beautiful car.

n2ojoe wrote: gunnarcove wrote: great video! your amx runs extremely  well....and is a beautiful car. don I appreciate it Don! That T/A in the video qualified quicker than my AMX, but I got a little lucky when he missed 3rd the last 2 rounds lol. The quicker car does not always win!

I have owned a 70 Ram Air 3 Trans Am, a 73 SD455 T/A. a 73 SD455 formula Firebird, and a 79 10th Anniversary T/A. All were 4 speeds, and I absolutely could not work those shifters anywhere near as fast as my AMX and SC/360. Thee were like shifting a truck. I always thought that I might have kept one if I had owned an automatic. They have a ton of torque.

Thanks Alex. I really like the Trans Am cars too, and I used to have a 77 400 auto. At the time, the pure stock drags had a 1973 year cutoff to compete. I would have built that car for the class if I could have, but ended up selling it and eventually bought my 70 AMX. Things have a way of working out sometimes.

Edited by n2ojoe - Jun/02/2022 at 7:11am

n2ojoe wrote: As far as the stock iron intake and exhaust manifolds, they definitely are a restriction along with the 4300 carburetor. What I have learned is that the combination of an increase of compression and a small duration, wide lobe separation cam installed retarded really works well.  We know that the limited induction simply does not support 390+ cubic inch over 5000 rpm, so I tried to maximize torque in the midrange. I have custom Race Tec pistons to max out the 1.5 extra point compression rule for 11.7:1. I currently have the Lunati 256 cam with 213/220 duration and 112 LSA installed 4 degrees retarded. It idles super smooth and the high port velocity makes killer throttle response and torque. It dyno'd at 369 hp @ 4900, and 450 lb/ft at 3500. I also think the small Summit cam would be a good choice for this combo. The T10 is a 2.43 ratio, rear axle is currently 3.73. The launch on the stock size Polyglas is tricky and takes a lot of practice. I try and hold 3000 rpm while staging, then slip the clutch and get rolling enough to feel the tires bite before fully releasing the clutch. An auto trans would sure be quicker, but I like the challenge of the T10. Shift at 5000, finish line is 5300-5500.

I assume that you can't run pump gas with that compression and cam? Your starting line technique is about what I used back in the day, except I was at about 2300 rpm. My car was totally stock and was faster shifting at about 4500.

n2ojoe wrote: Thanks Alex. I really like the Trans Am cars too, and I used to have a 77 400 auto. At the time, the pure stock drags had a 1973 year cutoff to compete. I would have built that car for the class if I could have, but ended up selling it and eventually bought my 70 AMX. Things have a way of working out sometimes. Did you ever test and tune your T/A's? I am curious of real world times from someone who has actually owned those awesome cars. All I can find in a quick google search is 14.2 for the 72 455 H.O. 4 speed, and 13.75 for the 73 S.D. 455 automatic. All the old 70 AMX tests seem to also be around 14.2, so it was a great pairing even before the cars were built for pure stock rules.

I never did time any of them, but what I researched back in the day was that the 455 H.O. and SD455 cars ran about high 13's to low 14's at around 100 mph. I remember one road test in which a magazine borrowed a privately owned stock SD and it ran a 13.7 with a 4 speed and 3.42 gears. Obviously an air conditioned automatic 3.08 gear H.O. would be at the slow end. I have several magazine tests of 390 AMX's and they usually did from 14.5 to 15.0 at low to mid-90's trap speed.