Ratio

[satanherself]

K,all you smart types,,This question has several involved. 350 HP motor,3 speed manual trans with a rear ratio of 4.27. Now,,is this a quick off the line but not alot of top end ? Is it hiway freindly ? Is it practical ?

 

[Tripper]

Low gears!

K,all you smart types,,This question has several involved. 350 HP motor,3 speed manual trans with a rear ratio of 4.27. Now,,is this a quick off the line but not alot of top end ? Is it hiway freindly ? Is it practical ?

Ms Herself,
Depends on that 3rd gear ratio but cruisin' the freeway would b hell in my opinion. I had a 4.11 & I was doin' 3400 rpm's @ 70 mph... made long cruises tedious & sucked gas. I switched to a 3.73 & now do 2500 @ 70 & get about 1.5 mpg's better. Also, I found it hard gettin' traction in 1st with a low gear like that but that also depends on how much HP u're runnin'. With a 3 speed I've found 3.50 to be a hiway friendly gear but as far a off the line... that depends on u're 1st gear.

BoB

 

[Gastrick]

Satanherself, I'm not very smart, but I will give it a try. That 4:27 rear is pretty deep for practical street use, especially with a three speed. There are more variables such as rear tire height and the actual ratio of the trans gears. But as a general rule, that rear ratio would make highway driving pretty miserable. I personally don't use anything lower than 3:50 in a car that I intend to drive at highway speeds for any length of time. Some will say that the popular 4:11 ratio is fine for highway use but my experience is that's a little to steep for an enjoyable highway cruise. Yes, the car wouls pull pretty hard off of the line with your ratio, but my guess is that it would flatten out pretty quickly.

 

[satanherself]

Well im trying to find a balance,,it's the 49 Caddy,,and the options I have are 3.77 3.36 and 4.27,,want something that could at least try and street race but also cruise at say 65-70 ,,yes I live in a dream world

 

[Tripper]

OK

So how much HP do u think u'll have?

 

[satanherself]

So how much HP do u think u'll have?

Shooting for 300-350,figure thats not asking to much,,Putting 365 heads on the 331,,med. cam
nothing over the top,,kinda just enough ya know

 

[Tripper]

Well im trying to find a balance,,it's the 49 Caddy,,and the options I have are 3.77 3.36 and 4.27,,want something that could at least try and street race but also cruise at say 65-70 ,,yes I live in a dream world

Ms Herself,
I would say 3.36 is pretty high. I like 3.77 as I find it to b a pretty good compromise but if changing them out is no prob for ya... it's always fun to at least drive around for a while with a real low one!!! Might take a little tread off u're tires like that though! ; - >

BoB

 

[Tripper]

Roller cams!

Shooting for 300-350,figure thats not asking to much,,Putting 365 heads on the 331,,med. cam
nothing over the top,,kinda just enough ya know

Ms Herself,
I like roller cams in 350's now. I flattened 2 Lunati's last year that weren't rollers. That SUCKS!!! After my experience... I always run a rev limiter now... especially if u're gonna street race! I use a 6000 rpm pill.

BoB

 

[satanherself]

well when I say street race I mean old fashion street drag racing ,,do they make a roller set up for 331 caddy ? also I'm old school,,none of those gadgets and such on my car,,hell I don't even like a Tach,,I figure if you can't feel and know then ,well

 

[Tripper]

My bad!

well when I say street race I mean old fashion street drag racing ,,do they make a roller set up for 331 caddy ? also I'm old school,,none of those gadgets and such on my car,,hell I don't even like a Tach,,I figure if you can't feel and know then ,well

Sorry... disregard! I thought u said u were gonna use a 350 motor. Doubt they make a roller for that Caddy but I could b wrong. I will say... redline comes up very fast with a 4.27 rear!!!

BoB

 

[satanherself]

Sorry... disregard! I thought u said u were gonna use a 350 motor. Doubt they make a roller for that Caddy but I could b wrong. I will say... redline comes up very fast with a 4.27 rear!!!

BoB

Yeah I would suspect so,,same theydon't make a 2 speed GM rear

 

[gassersgarage]

A good compromise is the 3:50 gear. I run a 3:50 gear in my 51' Ford but I also have a super T-10 4 spd with a 2:88 first gear. I had 3:42's in my Biscayne but it had a Richmond 6 spd with a 3:27 first gear. In my opinion, anything under 3:73 is not practical for highway cruising. Buzz of the engine, wear and tear, gas mileage and your friends will leave you behind. There's a winter cruise out here, put on by "Early Times", called the Early Times Winter Rod Run. Unofficially, it's called the "Great Race". Those guys go about 90 down the freeway. Most are pre-40's rods.

 

[joehalford01]

i think the 3.7 is going to be your best choice as a compromise

 

[oldschoolhotrods]

3.77 best bet for the 3 options you posted and for what you are wanting to achieve

 

[Lakota]

Herself,
I run a 327 Chevy with moderate HP. I did some research for a rear end and discovered that GM tends to use gears like 3:73/3:90/4:11 when using transmissions with overdrive. It gives a neck snapping take-off and low RPM's at highway speeds. If you're running a 3 speed trans with a 1:1 output in 3rd gear, then you might want to consider a 3:42 rear. It'll give a moderate take-off and low RPM's at highway speeds. We did this swap in a friends Camaro. He had a 3 speed trans with 4:11 gears. He was constantly winding the heck out of his engine between shifts, and it would scream at 3400 RPM's@60MPH. We swapped the rearend to a 3:42, now it cruises at 2100 RPM's@70MPH. The fuel consumption has dropped drastically.