I need a little info from the Rocket guru's on my 324 Olds. I am working on rounding up the parts to put the Rocket in my Hudson and like a lot of people I have the price of fuel in mind while putting this setup together. Other than being bored 30 over and running my Fish carb on it the motor will be mostly stock. Can anyone tell me where would the peak torque be (roughly) and where do these engines like to run for rpm's on the highway? I have never run one before and want to get it set up with the proper tranny and diff ratio's to maximize the life of the motor and to get some decent mileage. The car weighs 2680lbs with a full tank of fuel and no driver. Oh the motor is a '56 with #10 heads. Thanks, Ken.
Here's some basic engine and chassis specs to get you started. http://www.carnut.com/specs/gen/olds50.html
Thanks Clay, thats an awesome site, lots of info on there. I forgot to mention that I am going to run a manual transmission so what are you guys running behind your Rockets? 4 spd-5spd? what works for you? I'd also like to hear what your running for rpm's down the road and maybe some idea on fuel mileage. I'm all ears guys.
Most of what I see on hamb are using 3 speeds. Like early Ford flathead trans, or 50 Olds and the similar Cad/LaSalle, or stock 51-up Olds trans. Some builders like the old top shift transmissions, and want to use the old bell housings. If you go Chevy trans pattern, you need more money for the aftermarket bell. these Olds motors have torque for the heavy Olds cars, so you can use a low number axle ratio to get the RPMs down on a lightweight rod.
I am currently running a diff from an 87 Camaro with 2:73's. I have the complete manual 3 spd Olds setup, just wondering if I run it it might be revving a little too high at todays faster highway speeds. I currently have a sbc with a 2004r and at 60 mph it revs under 1500, a little too slow me thinks but it still gets up and scoots when I put my foot into it because of the light weight.
Somebody went to a lot of trouble posting all those old cars specs, God bless 'em! The only thing I'd like to have seen is what axle ratios that old Olds would have used. I don't imagine the Olds motor being terribly fuel-efficient, especially by todays standards. But with the torque peak around 2000 rpm it probably shouldn't kill you especially if you keep a razor sharp tune-up on it, And it probably shouldn't have any trouble pulling that 2.73 axle. A four speed with a little lower first gear should keep it pretty snappy from a standing start. An overdrive 5 speed might lug it down some in high gear. Time to do the math with tire diameter and gear ratios. Looks like the perfect excuse to install a vacuum gauge in the car to see if you can still pull some decent vacuum at cruising speed or if the engine is always lugged down. Sorry, I've just got a thing about vacuum gauges.
like the link above shows stock vehicle weight for '56 was around 3,700 lbs hp was rated at 240 @ 4400 rpm torque was 350 @ 2800 rpm stock transmission gears were 3.96:1 first 2.55:1 second 1.55:1 third 1:1 fourth and 4.30 reverse available differential gears were 3.64:1 3.42:1 3.23:1 3.08:1 your car being about a thousand pounds lighter should do just fine with the taller gears, whatever transmission you choose, although I would go for something with a fairly low first gear to avoid whiplash
Actually, when compared to the other cars of the day, Olds 88s WERE fuel efficient; the low first gear in the Hydramatic made 3.08 rear gears usable, when Fords and Chevrolets were still running around with gears in the 3.73 range. The 303 cars got as good mileage as the lowly sixes and flatheads, with more power if you wanted it.
I went to this site http://tri-5.chevyrides.com/rpm.php and calculated what my rpm's would be. With my tire size and the 2:73 diff and at a 1:1 ratio in whatever tranny I am going to run the motor will be revving 2074 rm @ 60 mph, that sounds pretty reasonable to me. Wouldn't really need an overdrive like a t5 except I do want to take it to the salt one day and try for the 130mph club. I have a four speed that I am taking out of my wifes '57 that I could use for now so all I would really need is the bell housing. I'm am trying to decide weather or not to sell the Olds 3 speed that is behind the 324 now as I am pretty sure I am not going to use it
The Jalopy Journal
