Hey Guys, I thought this question should be in the classic talk and not the classic tech section because the answer is pretty subjective. But thats what I want to hear.
I have a 67 fastback with the stock 8" rear end-it's coming out.
I recently installed a 347 stroker that I guestimate at 400hp/425 lbs of torque at 6000rpm. The transmission is a 5 speed TKO 600.
Here is my question. Whats a good street gear? I plan on running a 18" 285/35 tire with a trac loc posi. I want it to hook up in first gear at around 2000/2500 rpm or so with a soft/medium compund at 75 degrees of pavement temp.
I am wondering if a 4.11 is too radical. Any input would be greatly appreciated.
'Whats a good street gear?' What do you consider street gear? 0-30mph, 30-60, 70+ hwy? Be sure to be honest with yourself as to what 90% of your driving will be. That said, here's a neat calculator where you can add all your variables - tire size, rear gear, RPM, MPH and see what each gear size will do. I put them all into a spreadsheet so I could look across the columns and picked the gear that met 90% of my driving time. Randy's Ring & Pinion. RPM Calculator.
Jon
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'67 Coupe 289 C4, Candyapple red w/red deluxe int., PS, ext. decor group, light group, foxbody seats.
Next to install> stroked 333, AOD, 9" w/3.50:1, PDB.
'09 Black Warriors In Pink with glass roof - the wifes Mustang.
"If it ain't broke, I haven't fixed it yet" -Jon
I assume you are putting a 9" in. I also assume you are seeking advice based on personal experience. A third assumption necessary is the operating range of your 347, 2000-6000 rpm; probably peaking power around 5800 with a sweet spot from 3500 on up.
That being assumed, with the 5 speed, you need at least 3.50 gears. Personally, I think 4.11 is the maximum for any regular street use, even with the 5 speed. Personall, I have a 306 with an E cam and am running a 5 speed with 3.50 gears and it is just fine. Sure, 4.11's would get me down the quarter quicker but I don't go to the track often.
I think 4.11 would be a little low for street driving but with a 5 speed you can easily use 3.50 or maybe the 3.90. Try the calculator that Jonk67 posted and put in different gears.
Hi guys, great forum and thanks for the reponse to my question.
I'm looking for a good one two pull up to around 50-60mph.
I just want it to hook up fairly good. Not going to do any 1/4 mile stuff on a regular basis. I took a look at the calculator and when I punch in the numbers for my second gear ratio and a 25.8" tall tire I get 5760 RPM at 60mph (right in the sweet spot)
I think I have my answer. And yes, it is a 9" that's going in.
Thanks for the calculator.
Measure your actual tire height also, I found the tire ht. calc. to be off from my actual tire height.
Jon
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'67 Coupe 289 C4, Candyapple red w/red deluxe int., PS, ext. decor group, light group, foxbody seats.
Next to install> stroked 333, AOD, 9" w/3.50:1, PDB.
'09 Black Warriors In Pink with glass roof - the wifes Mustang.
"If it ain't broke, I haven't fixed it yet" -Jon
Hey RemRem, when you say highway rpms were good - at what speeds and where abouts where your rpms sitting? Mine is mainly for driving around town but I want to be able to take random road trips down the highway if I want. Thanks.
Need rear end gear ratio advice 
