Gearing question?

OK folks. Here's a question for all you true gearheads... As most of you know I am working on a 327 HO for my van. I also have a 2004R tranny to go with it.
My question is: If I replace my non-posi 3:73 rear end with a posi 4:10, what can I expect on the highway with the 4:10?

Thanks,
Dan

" I was told there would no math questions"
There are a bunch of conversion tables online to figure this.
You will need the gear ratios in the trans (some have those), the axle ratio and the tire height or circumference.
You can plug in the numbers and see what RPM it will be turning at a given speed (most often 60 MPH).
As a hint of what is a good RPM for an engine, you want an RPM that has enough torque so it will pull the hills without having to downshift. Too low is bad, low is better, high is just wasting fuel and engine life, and will wear on you. There isn't a set RPM, that depends on the engine, the weight of the vehicle and wind resistance ( a biggie for us). Usually a V8 will be happy with around 1800-2200 RPM at 60. The C5 vettes will pull 1500, but the package is not the same as a 327 in a van!

Dan your tire size is going to make a difference but I'm running a 4:11 rear now with a standard 3 speed and my highway speed is 60 since it's turning about 3000 rpm. And it's a 350 with the typical edelbrock 4brl & manifold and long headers. Yeah about 10 mpg. I'm running 225/60 16" tires. I really need to replace the seals on my 3:08 12 bolt posi, maybe I'll dig it out when it gets a little cooler and the afternoon showers take a break.

Thanks guys. Carl, assuming your 3rd gear is a 1:1 I guess I would have to expect about the same since I'm running 245/15's.

Anyone running with a 2004R on 15's?

Dan

350/ 4bbl /700R4/4:11 gears/about a 26 1/2" tall tire/1975 rpm @ 55mph/ 2200ish @ 60mph/ close to 13mpg/ Thats where I am at.