5th gear rpm's at 70mph

[b-radfromtheva]

me and a buddy from the area have been wonderin about this and couldnt get any help, a guy i ran across told me about the site and i'm hopin some folks can help me out, i run alot of highway miles and have a 99 cobra vert with the stock rear end(i believe 327's) and stock trans(i think t-45, help me if i'm wrong so i can edit). Some people have told me i need to get a set of 355s or 390s or 410s or 430s and some others, i run dead on 2 grand and just for comparison, could some folks post how many rpms you push in 5th gear at 70mph and what gears you have, hope to get some good help, this seems to be a huge forum:rockon:

 

[01yellercobra]

Look in the how to section. I think there's a spread sheet that will answer your question.

 

[b-radfromtheva]

Look in the how to section. I think there's a spread sheet that will answer your question.

i found it but the spread sheet doesn't pull up but thanks

 

[1badblownstang]

70 about 2400-2500 with 4.10's, 295/35/18's and thats if 5th is the same in a 3650. I drove to Nashville and back Friday (400 miles) round trip, did 78-79 the whole way, about 2800 rpms'. Wasn't bad at all, the headers make it a little louder than before, but i like loud.

 

[Un4GivN]

3650 here with 4.10's.. I wanna say I'm in the 25-2600 range at 70. If you tell us what you use your car for, it would be a lot easier to give you advice on gears.

 

[01SVTSnake]

Randy's Ring & Pinion. RPM Calculator.

Ought to help.

Personally with a 4.30 gear, 0.62 ratio 5th gear, and 295/35/18s i run 2400rpm on the dot

 

[b-radfromtheva]

i run some city, more backroad miles than city, and way more highway than both(since i live right in between auburn al, columbus ga, montgomery al, atlanta ga, some weeks i take it out of town to work for the week and its roughly 150 miles to the motel) i mostly run around 80-85 and have 245/45/17s and i love my 130 to 140+ runs, what gets me is even then i'm in 4th around 5,500 to 6,000, so really dont want to kill top end to much either

 

[Un4GivN]

i run some city, more backroad miles than city, and way more highway than both(since i live right in between auburn al, columbus ga, montgomery al, atlanta ga, some weeks i take it out of town to work for the week and its roughly 150 miles to the motel) i mostly run around 80-85 and have 245/45/17s and i love my 130 to 140+ runs, what gets me is even then i'm in 4th around 5,500 to 6,000, so really dont want to kill top end to much either

Lower gears will not kill your top end. They make 5th gear usable instead of the car falling on it's face. Your car will reach the same speeds, if not greater, and do it faster.

 

[b-radfromtheva]

Lower gears will not kill your top end. They make 5th gear usable instead of the car falling on it's face. Your car will reach the same speeds, if not greater, and do it faster.

it would be nice to get some use out of it instead of just cruisin, how bad do they hurt highway milage?

 

[b-radfromtheva]

how bad do they hurt highway milage? or do they?

 

[Un4GivN]

how bad do they hurt highway milage? or do they?

My car was geared (3.73's) when I bought it, so I'm not sure on mileage with 3.27's... but I was getting around 23-24 highway with those gears. I swapped out to 4.10's when I did my solid axle and I gained 2-3 mpg. I think I get great gas mileage for having 4.10's. I will soon be going 4.30 or 4.56 (can't make up my mind) when I build my sra.

 

[Bmeagher]

Best gear calc!

MFactory Competition Products - Forged Transmission Components

 

[matt87]

4.30s 2800 rpm @ 70 mph.

 

[b-radfromtheva]

yall say it runs with no problem on highway with 4.30's? i was thinkin about 4.10's but everyone may have me sold on the 4.30's

 

[Kn38ms]

I am at 2000rpm with the stock gears.


and yes, they suck....:sleeping:

 

[99Snaker]

Not for the faint of heart, but I run 4.56 gears to the tune of 3,000rpms at 70mph. They work GREAT in a tuned, naturally aspired bolt-ons Cobra.

 

[noel]

i have 3 cars with 373s most all run about 2700-2800 at 80
noel