nonhog

So I'm tempted to install my 455 I'm putting together in my latest find, a 74 Omega.
Its a mild build with a JM 20-22 cam 496./512 lift. 226/230 @.050
The Omega has 2.73 gears and I'm wondering if I really need steeper gears? my thoughts are a fun drag car w/o getting too carried away with
low ET and it would be driven to the track. I'm at least 20 miles from the closest track.

Convertor stall speed thoughts? w/2.73
Probably would shy away from anything higher than 3.42 (if I change gears)

I'll need to add a posi. I understand wrecking yard trucks I could find a variety of gears. Low buck build here so new gears and posi are not really affordable.

Would the BBO torque and a bit looser than stock convertor be o.k. with 2.73?

ah64pilot

First thing is first...that cam is 226/230 at .050" duration.

I have built that exact combo before and I had 3.42 gears in it. It was mostly street-able and ran fairly well at the track. With a 3,000 flash stall, 2500 loaded stall it ran 13.001 on BFG 295/50/15's. With slicks it may have gone mid 12's. If you are looking for those times you will have to step up to at least a 3.42 gear. I would assume 3.23 gears would only slow you down to mid 13's, but anything less you should only expect 14 second times.

I would not put a higher stall in the car unless you change the gears. That is a quick way to blow a transmission or snap an axle. It wouldn't do you much good anyway

nonhog

Fixed the cam spec. Thanks, doing too many things at once. I'm thinking since the Omega weighs less than a Cutlass I could trade of the need of the same gears. Nice to hear others history with similar set ups.

nonhog

Just thinking about this. Why would that be? Never heard such a thing.
Would axles snapping and trans issues but more so hooking hard as opossed to a lazy start?
Are you thinking it would be stressfull on those items if it bogs?

ah64pilot

The idea behind lower gears (higher numerically) is that they reduce the load on the engine. Higher horsepower in combination with lower gears allow the car to get moving QUICKER without as much strain on the mechanical parts. Think of a series of pulleys...the more pulleys you add, the less weight each pulley carries and the lighter the load is on you, the "motor".

Broken axles are caused by the instant power demand put through them while running slicks with good traction. The weakest link in the drive train will break. If you run slicks, and they hook, the next thing in line is the axles, ring and pinion, driveshaft, and transmission. As I mentioned above, lower gears reduce the stress put on these parts by "absorbing" more of the inertial force produced on "launch". IE: your engine spinning at 3,000 RPM and SLAM! those 3,000 RPM's are put to the trans, driveshaft etc. With the lower gear, it takes MORE engine RPM to move the wheels 1 revolution, thus reducing the 'load' put on the moving parts.

The reason I say DO NOT put a stall in a 2.73 gear car is that you are increasing the inertial load output by the engine, but doing nothing to decrease the strain on the drive train. If you run slicks, you have a better chance of breaking something and what gains you COULD see from the higher stall would be negated because the higher gear would "bog" the engine back down to get the car moving.

This is all so technical, I hope I did a good job of putting it in writing. If not, I'm sure some of the other guys could help me explain it.

507OLDS

We ran that cam is a real basic +.030 455,in a 70 Cutlass Supreme,bench seat,column shift,and it ran consistent 12:50's. We swapped gears from 3:90's to 4:10's to 3:73's,and the ET's stayed the same.We swapped from a Performer to a Torker,and the ET's still stayed the same.
You could run a 3:23 or 3:42,to make it highway friendly,and run an 11" 2200 stall converter.