[JACK_BURTON55]

Is this even possible? i mean calculating in out, i could do 75mph at only 5477 rpm. This is insane, could the the TH350 even take it? the manual says to not go above 40mph in first gear.

http://www.chevellecd.com/66cd/tech/calc_rpm.htm

[BVR421]

yes it is possible, no dont do it
the trans will take it but your 350 probably would do it one time only

[69Customs]

I run a 350 with 2800 summit cam and she runs up to 5640 all the time and there aint no more! Just flat lines.
Go for it!

[JSchmitz]

My first GTO had 2.72:1 gears in it. I think I used to shift out of first at about 55mph. It would bark the tires too. That car would scream on the highway. You can't be scared!

[pontiac6269]

All my cars have had 2.73 gears. When I raced I would shift first to second at 6000 rpm and go through the lights at 6000 rpm in second gear.

[Half-Inch Stud]

I can only imagine the 2.41 (or sicker) Pinion head dancing around inside the housing, with the instant "seize the moment" lockup jam between the diff & case floor.

[Ben M.]

Don't do it. There's really no need to, even if you just want to see if it can be done.

Not to mention you do have losses not being factored in, which may make the RPMs higher at 75MPH than the calculated values.

[Skip Fix]

FWIW my TA with 2.56 rear gears and a TH 350 could do most of the Texas World Speedway road course in second- close to 90 mph. Did need third for the last curve onto the ovla's long straight. It also was barely in 3rd in the 1/4 with a fairly stock motor.

[JACK_BURTON55]

lol this is interesting. I think its kinda funny, talk about tall gears, i dont think i would ever do it though because id like my cars engine to last me through college, well the whole car actually. I do get on the car sometimes and that 2.41 feels best at 85-90 on the interstate going through Atlanta manuvering through traffic.

[rtanner]

it would be better get going about 65mph in 3rd and then snatch it down to 1st while simultaneasly flooring the throttle! then it wont take so long to get 75 mph, once you get use to driving your car like that then you can graduate up, running up it to 50 mph or so in reverse and spinnig it around and going forward with out loosing any speed, and snatch it back to low and run it up to 76mph again, your car will love it you will love it, if you film it we will love it! happy thanksgiving

[Thumpin455_GTO]

Why wouldnt it run 5500rpm? A 350 could turn that no problem provided the valves dont float. The pistons are lighter so the rods are stressed less at higher rpm than a 400 or 455 and they will pull 5500 no problem.

When I was still driving the 10th TA it had 2.73 gears and would shift out of first around 62 mph, the 403 would float the valves over 5200 so it never went over that. That car has a stupid high top end for only a 403. It pulled 5000 in 3rd without any effort, but I wouldnt suggest our friend Jack attempt that because with 2.41 gears that is really moving. Just enjoy the low revs on the highway and better mileage when you are cruising 70mph on I-75. Just drive intelligently, not like you have a Civic with three wings, neon lights, and a fart can under the bumper.

[Skip Fix]

My TA with the stock 180 hp 400 would only pull 4000 in high gear, 130+ though.

[Danimal]

I had a '79 malibu Landau in high school that had a 2.29:1 gears. That's right. 2.29:1. When I bought it, the 267 v-8 was dying so I dropped the 283 in it from my '64 Impala that was very well built (forged pistons, shotpeened rods w/ARP bolts, balanced, better springs, ect) and with a 3" stroke it would turn 6,500 rpm easy. While it wouldn't drop any jaws when launched, that thing would absolutely fly in first gear--75 MPH easy. :-)

It's a different feeling in my '69 with the 3.23's, as I keep waiting for another upshift to occur. :-)

Happy thanksgiving, guys!

[PITTSBURGH 64]

I love having a 2.56 with my RA-4 cammed 462. However I have a 4 speed hydro...
http://www.youtube.com/watch?v=jH95PE4P-Ow

http://www.youtube.com/watch?v=H0CCMnOu97U

[Overkillphil]

Originally Posted by rtanner

running up it to 50 mph or so in reverse and spinnig it around and going forward with out loosing any speed...

J-turn. Jim Rockford!

[dmac]

There's nothing like idling in drive at about 80 mph, cruisin down the freeway, with all that power available just by dropping into 2nd. Exhaust just at that vibration stage, engine running at 180 degrees. That has got to be easy on the engine, and doesn't feel like it burns much gas, even though you can see the needle moving.

[Region Warrior]

Not apples to apples, but my st300 shifted on its own at 70-75 mph with 3.23 gears.
Didnt have a tach, so no idea what the rpm was.
Never did find out how fast it would go cause at 145 mph the car(68 FB) would start to float.

[Thumpin455_GTO]

Low gear in the ST300 is pretty close to 2nd in a Th350/400, so you will be able to go a bit faster in low than you can in 2st with the 3 speeds. The 700R4 and 2004R have even lower 1st gear ratios, the 700 has a 3.06 where the 350/400 have 2.52/2.48 first gears respectively.

High gear in the two speeds and 3 speeds is always 1:1, in the 4 speed autos 3rd is 1:1 so mph will be pretty much the same in those gears provided the converter isnt locked or slipping excessively.

Fun with numbers. a 2.41 gear with a .62 OD in the 2004R, a set of 28" tall tires, and 5000 rpm = 278 mph.. Stupid fast huh? At 1500 rpm you are traveling around 83mph with the same setup.

You would need at least 5700 rpm and 28" tires to go 145 mph with 3.23 gears, provided there is no slip.

[gunmetalgray67]

My 76 TA had 2.41s, TH350, and a very mild 400 (headers, Performer, .450 lift cam) and ran 14.97 @ 100. I did not shift out of 1st until the 1000' mark. It would do over 80 in 1st. I outran several Ducatis on the highway. I outran a 95 Stang on the highway and never took it out of second gear. When I stayed out of the throttle I got 18 mpg.

[Pontiacman469]

Ditto:I Had a 78 Olds cutlass w/a 260 oldsulled it and put in a 307 w/turbo 350 I think it had 2.14 or 2.41 gears.I could "chirp" the tires when i shifted into second around 70mph..slower than hell out of the hole tho.