no engine isnt stock it has cam intake headers carb...the engine is out of a 1974 chevy turck its a 350 btw

 

are you talking about an older 3 speed manual or a TH350 auto that came in the 81's?

 

Final drive would still be 1:1, unless you're curious about the intermediate gears. I was curious about the whole equation though.
Engine RPM = mph x tranny final drive x rear gear ratio x 336, divided by tire diameter.
So... 157 x 1 x 4.10 x 336 = 216283.2. Divide that by the tire diameter of 27.1" and his RPM's at that speed are 7,980. He's right on the money!

 

Thats pretty cool, i didnt know how to figure that. So, like you said, he was right on it. That suckers spinnin some rpm's too.

 

lol i did have a pretty bad *** car untill the damn tree crushed mine but hell give it a month and she should have a complete new shell.. ill have to post some videos on here.

 

I have 373's in my 79 and at about 55 or 60 mph it is running about 2800 to 3000 rpm..I dont drive it much on the interstate so it's ok for me but if it was a car that I drove alot I would be changing them out for sure...

 

If you put a 3000rpm stall in your car with a set of 355 or 373 gears with a posi unit in it,You should get descent gas mileage and have no problem roasting the tires off of it.ps you may want to invest in set of drag radials so you can really hook hard and go.

 

3.55 gears are for 8.2 rear ends, 3.5, 3.55 and 3.6 are available for Ford 9's. If he's running a stock 8.5 in his car then his only options in that range are 3.42, 3.7 and 3.73 for gearing. I know of no aftermarkets for a 3.55 in an 8.5. I wanted a 3.5 - 3.6 rear gearing but I couldn't get it unless I went to a Ford 9 or weakened my rear down to a 8.2 rear. Since the pinion is the same for the big 10 8.5 and the 12 bolt I just stayed with my 8.5.

Also, unless he's running a lockup converter in a newer style transmission a 3000 stall from over stock will eat up his gas mileage pretty easily. Just going from a 1800 to 2300 in mine dropped the gas mileage by about 2 - 3 mpg. A couple of the guys I know that have 3200+ stalls don't even take them on the freeway anymore (if they can avoid it) and one has gone back down to a 2500 stall.

 

well im looking to get 3.55 or 3.73 gears to go with my 383 but i drive on the freeway quite a bit..and i want to get a 4 speed but in the mean time i might just have the stock 3 speed..so is there a way to scrape some better mileage out with those gears? what stall converter should i get to salvage any mpg? and what milage do you think i would get?

 

If you're looking for mileage then I don't think you should be going for lower gears and a higher stall without having an overdrive gear or two if you're going manual or a lockup converter if you're going auto. A four speed will help a little bit but it still ends with a 1.0:1 ratio just like your three speed automatic. Manual's are just more efficient and will help you some there a little. You can get a 5 or 6 speed manual or an automatic with overdrive and benefit greatly while still going to lower gears and still get better gas mileage for highway driving. Your street driving will benefit on launches but you'll still eat gas at the lower speeds. OD's help on highways.

This link will help you find all the gearings on most Camaros...