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San Diego Car Guy

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Discussion starter · #1 ·
Dave,
How do you like your 3.42's? I have 4.11's and they are too high for much freeway use and was thinking about going with 3.55's.
Paul
 
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#2 ·
Re: Black CA license plate process?

I like the 3.42's. I have an Autogear M22W which has a 2.54 1st gear. I'm glad I have the torque of the 383 for 1st gear take off. Anything with less torque would be like taking off in 2nd gear all the time. 1st gear is real long legged but 4th gear cruzin' @ 70 is 2800 rpm with 255/60r15 on the rear.

If I fatten up the primary jets I get better 1st gear take off. I have leaned the primarys down to 67's with a 650cfm vac. sec Holley to get better mileage around town.
 
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Discussion starter · #3 ·
Re: Black CA license plate process?

Unreal said:
How are transmissions and California black plates related? :)
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Simple. I am the OP and I chose to take the thread to another topic. LOL
 
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Discussion starter · #4 ·
Re: Black CA license plate process?

Fred Mertz said:
I like the 3.42's. I have an Autogear M22W which has a 2.54 1st gear. I'm glad I have the torque of the 383 for 1st gear take off. Anything with less torque would be like taking off in 2nd gear all the time. 1st gear is real long legged but 4th gear cruzin' @ 70 is 2800 rpm with 255/60r15 on the rear.

If I fatten up the primary jets I get better 1st gear take off. I have leaned the primarys down to 67's with a 650cfm vac. sec Holley to get better mileage around town.
Click to expand...
I have a 700R4 with a 3.something 1st and a 383 but a little taller tire, so I should be fine starting off with 3.55's. But I am surprised you still turn 2800 at 70 with 3.42's. Is your 4th a .7OD and does the Autogear lock at speed like the 700R4?

Thanks,
Paul
 
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#5 ·
His Autogear is 1:1 in 4th and 2800@70 is about correct as 3.73:1 would be 3200 rpm.
I know, I have two vehicles w/3.73 and stock size tires and both show the same.
 
Discussion starter · #7 ·
JodysTransmissions said:
Autogear M22W is an aftermarket manual 4 speed transmission and 4th gear is 1:1. You can't compare your 700r4 to this but, the 2800 rpm x .70 would be 1960 rpm.
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Thank you. 1960 rpm sounds a bit low for 70mph with a SB. Wouldn't you agree? I better go with 3.55 like I thought.
 
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#8 ·
My '68 Camaro has a 350/325 hp, 200-4R BTO Level 2 with 2200 stall, '74 Nova 8.5" Tru Trac 3.42:1, 225/60 x 15 BFG's. On country roads the tranny likes to shift into OD around 42 mph. So if not on the fwy I keep the tranny in third. On the fwy in overdrive 70 mph is 2030 rpm. Wish the rearend had 3.73 gears as BTO suggested/recommended. I got a good deal on the freshly built 8.5" and couldn't turn it down. Very happy with the close gear spacing of the 200-4R. Big improvement over a TH350.
 
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#9 ·
San Diego Car Guy said:
Thank you. 1960 rpm sounds a bit low for 70mph with a SB. Wouldn't you agree? I better go with 3.55 like I thought.
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not really - depends on your cam. my LS1 runs about 1600rpm at 70 and it drives great - stock cammed but add a lumpy cam and I'd need to be in 5th gear - and it has 3.42's in it - God I love O/D trans!
 
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#10 ·
Save the money from the gear change and put it towards an OD trans. Just as a general statement, the primary job of gearing is to multiply torque and put it to the ground. The unfortunate side effect when you limit yourself to a 1:1 top gear is high engine speed if you want to use the car on the highway. Changing the rear gear to compromise can result in the regret of losing some acceleration. Something like a TKO-600 would drop your cruising RPM to 64% of current in top gear but not let you lose that "finger on the trigger" feeling around town that you get with that steep gear. Even better would be a six speed with that 4.11. The extra ratios also usually give you more opportunities to put the car in the sweet spot when you need it or want it from cruising speed, depending on your power curve of course.

Besides the car in my signature, I have another one with a hot little solid lifter 327 with Muncie and a 4.10 geared Moser. I haven't even attempted to drive it on the highway. I was trying to explain gearing to my wife a few weeks ago. We were driving the 4.10 car down the road by our house doing around 60mph and I said, "Put it this way....in the other car at this engine speed in top gear we'd be doing over 100mph right now." Of course, I built that car from the rear forward so I set my engine up to work with the rear gear and trans. I still wish I had put in just a little more gear.
 
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#12 ·
BPOS said:
Steiner, you fuel, he has a 700R4 :) Nice post, though.

I think a 3.73 would be perfect.
Click to expand...

Oops. I kaynt reed.

God. How is first gear even usable? With 2.87 first and 3.42 rear it seems like I'm at redline before my foot hits the carpet.
 
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#14 ·
THM700-R4 has a 3.06:1 first gear. Remember, when these trans were designed and built, rear axle ratios were less than 3.2:1 and the theory was to reduce highway rpm as much as possible. So, 1600-2000 is norm.

Now, couple 3.06:1 to a 3.73 or higher ratio, redline is reached in 20 foot, maybe 25 feet if 2-bbl equipped.
 
#16 ·
The 700r4 was put in a lot of large cars and trucks, an 80something suburban with a pathetic 350 needed every bit of that super low 1st to get going.

I had a 700 and 3.55 and I was glad it was an auto because shifting before you get to the other side of the crosswalk from a stop would get really annoying.
 
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