Easy (?) OD Auto Install
Thanks AJ. Running 3.55's but would probably go 4.10 with OD.
Hang on Joe;
with 4.10s your cruise rpm will be about 65=2285 with 27" tires. This rpm works well with about a 220* or less cam. If you run a 230 or more,the intake will get to be muddled up enough to not return the decent fuel economy you were expecting. So you kindof need to tie cruise rpm together with the cam.
At the other end, your starter gear is 2.74 x 4.10=11.23,
I like to gear my combo to powerpeak in
second gear at just before 60 mph. This will give me the best chance at ET'ing in the shortest time.
So in this case about the closest you can do is in fact, the 4.10s; which will get you 60=4710 at zero-slip, say 5400 with 27s and 15% slip. That's looking good. But the starter is now 11.23 quite a high number for an automatic.
Lets try it with the A518, which has the 904 ratios.
With 4.10s and 27s, 60 is now 4430/5100@15% slip, and the starter is 10.05, still high but better, IMO.
So now you pick a gearset, and cam your engine to make it happen.
In either case , 65= 2285, so a 220*@.050, or less, cam is about right for that cruise-rpm. You can do it with a 230 cam, but a hydraulic 230* will not do well in the fuel economy arena. I have had both a 224 and a 230, and at 11/1 besides. 224 did well, while 230 not.
If the engine is already built, and has a 230* or bigger cam, then 2285rpm is on the low side to cruise at, for fuel efficiency. My 230* cammed combo cruises at 2240 , and I stopped logging fuel mileage in about 2006 or so,lol.
In anycase; HappyHotRodding
