I've been wanting a chevelle for quite some time now, mostly as a weekend cruiser. I've finally decided on a getting a 1965 model and have some mods planned for it. As it is going to be a cruiser, I don't want to use extremely short gears as I don't want to be crusing down the highway at 4000 rpm doing 65 mph. With my tire size I think 3.31's would be a good compromise, as that's about 2800 rpm at 65 mph. I realized that using this tall of a gear will affect my 1/4 times as opposed to 4.10's and 3.73's and even 3.55's, but really, I just want to hit mid 12's.

Phew, I guess I'm being windy, so my real question is this, is anyone else using 3.31s? Anyone have any regrets about using them? Anyone have some real world experience with 3.31's?

If you want some more information, I'll probably be using an m-21 if I can get my hands on it, if not I'll be using an m-20. Most likely I'll be building up a budget 383(probably something from flatlander racing) with AFR 190s and a performer RPM intake. MY only concern is picking out a cam that will match up well with my gears, and deciding on wether I should go with a 650 or 750 cfm carb. Any advice is appreciated.

I'm sorry for such a long post, I know I'm asking a lot, but I think eventually, I will be able to return the favor by helping out in return smile.gif

That is kind of a loaded question. You can't compare car A and B when the only thing in common is the diff ratio.

If you want good ETs with a somewhat high gear, you need to build for torque. 383 would be OK, a 406 would be better. A big block would be much better (isn't it always?). Stick with a fairly mild cam, something that makes power to 5500-6000 or so.

If you want to solve the cruise RPM vs. ET problem, get yourself an OD trans. You can then have low RPMs on the free way, and great ETs. I hear there are some good kits out for this now.

I am running 3.31s in my GTO. I do have a Richmond 6spd with a 2.77 first gear, so that helps a bunch. I guess my responce is pretty worthless to you...LOL...Its not really apples to apples.

I did run low 12s with a little set of slicks and a 502.

So can you be quick with 3.31s? Sure, but you need to build torque with your engine or through transmission gearing.

Andrew

I've run a best of 12.99 with 2.73 gears and will be going to 3.31's over the winter.You might as well scrap the idea of an M21 with those 3.31's if mid 12's are your goal..maybe a T10 with a 2.88 1st would be a better choice IMHO
I think low 13's might be do-able with an M21/3.31's and a torquey 383 if you can get some stellar 60 ft times.Stick with a short tire too..no taller than 26" MAX or you'll "kill" the gear.

I am close with 3.42's

I'm sorry, I know the questions were jumbled all over the place, I was right on my way out to my last class so I was trying to fit everything into one post and it got a little confusing.

I guess I'll probably be using an m20, I believe they have a 2.5x first gear, and are built like rocks. With the 383, if I get my came right I should be making around 430 ft/lbs at 3600-3800 rpm and probably no less than 380 ft/lbs from 2300 rpm on up. I've had no problem getting sub 2.0 60 ft' times on street tires, usually in the 1.89-1.95 range, and I've done so on a number of different limp noodle chassis, so I think I could manage in the chevelle. I guess I will just have to experiment when the time comes, maybe email some camshaft manufacturuers for some cam recomendations.

Originally posted by mr 4 speed:
You might as well scrap the idea of an M21 with those 3.31's if mid 12's are your goal..maybe a T10 with a 2.88 1st would be a better choice IMHOditto
The M21 would give you 1st gear final drive of ~7.3:1, which is pretty tall. Even the M20 @ ~8.5:1 (assuming a 65 & earlier M20) is tall.

ST10 w/2.88 1st (I think there is even a ST10 with a 3.44 1st gear) or taller gear with an OD trans... my 2¢

If you (or anyone) have MS Office 2000 & would like a copy of the Excel spreadsheet I made for gears, tires, trans, and speed let me know (email).

Originally posted by backus101:
I've had no problem getting sub 2.0 60 ft' times on street tires, usually in the 1.89-1.95 range, and I've done so on a number of different limp noodle chassis, so I think I could manage in the chevelle.Cool,but with a manual trans in a 3500# +/- car making over 400 ft/lb torque?

Originally posted by mr 4 speed:
</font><blockquote>quote:</font><hr />Originally posted by backus101:
I've had no problem getting sub 2.0 60 ft' times on street tires, usually in the 1.89-1.95 range, and I've done so on a number of different limp noodle chassis, so I think I could manage in the chevelle.Cool,but with a manual trans in a 3500# +/- car making over 400 ft/lb torque? </font>[/QUOTE]Not quite 400 ft/lb, about 370 ft/lb with 3.73 gears, and a 3.36 1st gear, 3300 lb car weight and 190 lb driver; however, the car was equipped with a torque arm and drag race stabilizer bar. It may take some practice, but I think I can manage it. I would think taller gears and less torque multiplication would make lower 60 ft. times easier, but I might be wrong. I should specify most of the above runs were after a LOT of practice, usually 10+ runs. I may just end up going with a big block and an automatic, it looks like it'd probably be easier.

In my experience (which isn't too much with manual trans), more torque, higher gears and slicks = big load on the clutch. I've been in a similiar situation, and it was difficult to control the clutch for best 60' times. But again, I haven't had a whole lotta experience with this.

I am running mid 12's with 3.08's in my Nova with 1.85 60 ft's. I don't think a 65 chevelle will weigh that much more. I have a 383 thats probably making 460 hp at the moment and at least 400 torque (all a guess of course ;) ). I have a th-350 with a 3500 stall which probably also helps. I think its doable with 3.31's

We have 3.23`s
So far with drag radials.. 1.81 60Ft 11.67 @ 119

I used to have 3.36 gears in my car. Running on 215/70/15 Radials and a Super T10 4 speed my car went a best of 12.40 @ 116MPH.

While not 3.31, I ran a best of 11.87@116 with a hydraulic cammed 454 (461, Richmond ST-10 4 speed, 3.55 gears and 28x9 slicks. What a ride smile.gif

When I 1st ran the car I have( 64 Malibu ) It had 3.31 gears and 26" tall " Lee Manhandler " Radials Car ran 12.80's @ 110 in 2nd gear w/ T400. Had a real nice 355 in front of it. Car was a real Dawg off the line ( 2.10 - 2.20 60') but it just took off after about 100'. I had the car down to approx. 3200 lbs w/o me at that time.

I currently have the 3.31 gears. I ran a best of 12.81 with a 28in tall Drag Radial. As Mr. 4-Speed stated, kinda "killed" my gears. For cruising they are great. I have changed the goal for my car to be more strip oriented, so the 3.31's are coming out. It all depends on what you want out of your car.

Please remember that way back in the late '60's/early '70's, the REAL MOPAR big cars ran 727 torqueflites and 3.23's behind 383's and 440's and such AND RAN LIKE BAT'S!!!

Roadrunners and Satelites and GTX's and such cars..... My wife's girlfriends boyfriend, (later hubby), had a new '67/'68??, 440 tri-power GTX H/T that just sat back, raised up and took off like a shot when we double-dated way back then as kids!!

The motors made a bunch of midrange grunt to do it!!

pdq67

Think about a 3.42 low ST10. They are the most common and will make launching much easier than with an M20. the second to third spread is a little wide but no worse than third to fourth in an M20. With a mild torquey 383 it should work real nice.

even thou i cant compare my trial and errors to what you are about to do....there might be alittle info in my post that you might learn from....

i had this idea of running a 2.41 posi track in a 4000 lbs car with a bbc and have it run 13's as a daily driver........very low rpms on the highway but yet have topless top end mph...

let me say it has been a very long summer of trial and errors......i had to throw all the common knowledge of picking parts out the window..(build for torque)...match the cam to the gears and the stall and the intake and carb ...bla bla bla i couldnt go that route cause my car would have never ran better then a 16 sec. 1/4 lol...

it finally came down to build the motor like the car was geared with say some 3.73 and just leave the 2.41 in there

so here i am with a mod.750 holley single plane intake big o'l cam 233/239 10.2 to 1 comp. and now a 2800 stall and the car is running better then it has before with smaller cam and less stall and stock style intakes......i moved my shift point from idle to 5000 to 3000 to 6500 hadto i needed the rpms to get the car moving......

i know with my few changes ive made in the last month or so im in the higher 13's now....which is my goal for this project.....

my engine make about 300 hp to the ground based on the trap speed it(last run out) runs and my car is alittle lighter now too.it was 4060.....

im kinda walking away from this as if you want to run 12's build the motor like it would need to be to run 12's and just throw the gears in that you want......

ive ran low 12's in street trim with 3.70 gears and bf stock tires 275/60- 15 with some 1.70's 60 ft times.......but that was with an auto and 7000 rpms shift points......kill the torque so i could hook up on the line.....

Back again..

Try to get use of copies of both D2K and Drag b/c you can imput D2K's power numbers into the Drag program to tell how you will theoretically do!!

I know they are sim. programs so just look at the trends in changing parts and gears and tires and you will see a pattern that may help you..

My 550hp 496BB at 5500rpm per D2K in my '67 First Gen. car with and M-20, 3.31's and about 26.5" tall hi-po tires theoretically should go like 10.5 and right at 129mph if it can hook up!!

Again, I know both are just sim. programs so will be happy with say an 11 to to low 11's!!!

pdq67

PS., and the guy I bought my car back from had a warmed over .040" over 327 in it that he said with no more then a small set of real slicks got a 12.9 slip from a So. Cal. strip.... He said he could dig it up for me if I doubted him!!!

in my sig is my car a 1985 vette with a 307 gear on the motor through the exhaust 10.91 at 125 mph

With an open differential and a 3.36 gear, my car has run a best in 8th mile of 8.86 at 79mph .I have never run the 1/4 but I think it's high 13's. With more gear nand better heads it is going to run faster.

I have a 3.31 final and occasionally race on 25.375" BFG Drags. 3.04 1st gear though. Easy clutch let off, soft 2.05 60', 12.26, 118.75 mph. It has a bunch more in it once I decide to step off the clutch at 5000 ( ASSUMING the chassis holds).

One idea you can take away from that is the use of slightly smaller tires like the 275/50s I use or 235/60 for a slightly smaller foot print.

Do the math, 3.31s with a 25" tire = 3.73s with a 28" tire.

i'm close with 3.73's and i like em'

Originally posted by 427L88:
I have a 3.31 final and occasionally race on 25.375" BFG Drags. 3.04 1st gear though. Easy clutch let off, soft 2.05 60', 12.26, 118.75 mph. It has a bunch more in it once I decide to step off the clutch at 5000 ( ASSUMING the chassis holds).

One idea you can take away from that is the use of slightly smaller tires like the 275/50s I use or 235/60 for a slightly smaller foot print.

Do the math, 3.31s with a 25" tire = 3.73s with a 28" tire. Sounds like you need to put a small slick on it and drive it like you don't have a dime in it! That thing'll fly! Put a 7200 chip in it and mat it on the second yellow. That's GREAT fun in a stick car. :eek:

Randy

Randy, I'm gun-shy with this bastid. I fragged the 11" GM HD clutch and bent a frame brace when I first got the car , pounding the thing ( and since then have put a bunch of $$ and time into it).

You are absolutely correct Sir. The well-designed retro 435HP mill is really making steam, now I have to drive it like I stole it. A decent "metal bending" 60' will net it high 11s. And its pure street, 15 mpg, drive 1200 miles to Nashville, no problemo. Couldn't be happier with the ride.

Again, to stay on point. 3.31s with a deep 1st gear will get you way into the 13's/ OR the motor should be a very large ( 454+) STUMP PULLER! Then it's up to you to "tune" it to run low 13's or high 12's! :D OR TEN's if you go MEGA-RAT!, ala Tom Baird, whose ride is also very streetable.