flywheel

iTrader: (2)

Got the combo set up in my 66 chevelle sedan, it has currently 2.73 gears. Im running a 3200 stall revmax convertor, 6.10" lift cam 2.23/2.39 duration on it....Will it really hurt anything to use the 2.73 gears? It should have great top end for sure....! opinions welcome...
Rick

Jimbo1367

It will work obviously, and give better milage. Many people on here suggest no higher (numerically) than 3:42 rear with a 4l6o as they simply useless in first gear.

ART T

I had a 1970 Chevelle with an LT1, 4L60e and 3.42's. It was a very nice driver.

flywheel

iTrader: (2)

anyone else?

aknovaman

iTrader: (7)

The 2.73gears will make just about any vehicle a slug to drive in town with horrible aceleration even with the added low end tq of the 60L.I have driven several 273 gear cars and they stink.

1989GTA

I would go with the 3.42s from my experience. 2.73s is way to tall for any kind of performance.

oldgoat69

Tire size will influence the choice, but I agree with the 3.42 or even 3.23. Since you need to change gears, you might want to consider a swap to the 8.5 axle. 3.50 is the closest to 3.42 for the 8.2 that would be stock in the 66.

lemons12

iTrader: (71)

Since when?

Grab some stock 3.42s or 3.23s if you have the option.

1967BuickGS400

Performance wise I dont think it will make alot of difference. I have a 71 skylark with a 455 and th400 that had 2.73s and I ran 14.01 at 97 mph. I change to 3.42s and ran 14.01 at 95mph. The car feels like it pulls alot harder with the 3.42s but I guess not. I would say with an overdrive go ahead an change them it will feel better for cruising.

aknovaman

iTrader: (7)

Your 455 has significantly different tq curve than a lsx engine that affects how it will accelerate. Apples and orange comparison.

mantycarguy

I run a 3.73 gear with 26 inch tall tires, 327cid small block with fuel injection in my 68 nova and still only see 2450 rpm at 70 mph.As far as 1st gear being useless, I can tell you that
this is a perfect compromise between great acceleration and reasonable fuel economy. I average approx. 17 mpg on the highway with this setup.

flywheel

iTrader: (2)

Ive had 3.55's in several of my other cars, included my 71 w/6.0/4l80e in it now. So, I know it would be better with something like that, but was wondering if there was any real down side to the 2.73's. Ive just got it up and running and tuned but the 4l60e is now slipping so it's out and at the rebuilders now..But what few miles I did get to put on it it seemed to do fine. Didn't have any trouble breaking the tires loose even at 65mph..Course, the streets and tires are real cold now. Guess I'll just wait till I get it painted and back together to decide...
Tuner said it was doing about 170mph in 3rd on the dyno...yikessss
Rick