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Old 09-09-2011, 08:33 PM   #1
Breadman
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What do you think ?

I traded for a 73 chevy C-10 long bed. It HAD a 250- 6 cyl in but it has been replaced with a 1965 model 327. It still has the low gears in rear end and the 3 speed that was used with the 250. It sounds like riding around in 2nd and has
bad gas mileage. OK here is the question.For better gas mileage would you !!!
1. Leave the 327 in it and just change the gears to 308 or so.
2. Put a 250 back in it and leave the gears along.
3. Or do you have a better idea, If so tell me about it.

Truck will be used for daily driver and pull my boat

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Old 09-09-2011, 08:36 PM   #2
Clyde65
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Re: What do you think ?

I would put a 4speed auto in it, or a 5speed manual. That would make it easier on fuel...well a little easier.
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Old 09-09-2011, 08:38 PM   #3
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Re: What do you think ?

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Originally Posted by Clyde65 View Post
I would put a 4speed auto in it, or a 5speed manual. That would make it easier on fuel...well a little easier.
what he said, low gears for towing and an over drive for highway
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Old 09-10-2011, 10:02 PM   #4
Breadman
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Re: What do you think ?

That is all well and good and might do that if the funds were there.If I go the way of
just changing gears I'm sure someone around home would trade for the 411 or 373
that's in it.Have not checked to see what's in it yet. If I went the 250 way I know
somebody would give there 6 cyl for this very goon running 327 I have.
Thanks for the help.........Still looking for more
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Old 09-10-2011, 11:40 PM   #5
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Re: What do you think ?

gonna state the obvious. drive a honda. buttttt id reccomend a th350. u know itll fit. get it from a truck of similler year. a 5sp manual would b slick but ur lookn at alotbof custom fab
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Old 09-11-2011, 02:17 AM   #6
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Re: What do you think ?

Swaping from a three speed manual to a th350 will not improve your mileage enough to justify the cost or effort. First, determine what rear gear it has and go from there. 3.42-3.56 is a good all around ratio without OD, in my opinion. I wouldn't go less than 3.23.
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Old 09-11-2011, 05:36 AM   #7
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Re: What do you think ?

Congrats on the new truck and welcome to the forum. Pictures are always welcome.

What tranny do you have? What carb? The 250 is not that economical. What type of driving do you do? If your driving is relatively open areas, as opposed to congested city driving, a 700r4 would work well. That may be a cost that doesn't fit your budget at this time. If the 327 is well tuned, has a 4-barrel with small primaries and can breathe well it will do better. You might be able to make your mileage better. It will always be low.
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Old 09-11-2011, 07:04 AM   #8
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Re: What do you think ?

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Originally Posted by 67_SS396 View Post
Swaping from a three speed manual to a th350 will not improve your mileage enough to justify the cost or effort. First, determine what rear gear it has and go from there. 3.42-3.56 is a good all around ratio without OD, in my opinion. I wouldn't go less than 3.23.
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u can find a 1000doller parts truck. What rebult standard can u find for that? I have 311s and get 11mpg if i baby it. These trucks are square. To make it efficent is nearky impossible. Yes a 700r4 is the smartest thing. But forsomeone without a welder or oxysed torch installing a non factory transmisson is not is not cost effictive. If he.puts any taller gears in there all power is gone. Infact worse gpm is possibke due to more struggle to start after a stop. Sense the truck us a stock 6 shes got gears. To slam taller in there will indeed worsen the milage unless the car sees 75% highway. Cost effictive.
Posted via Mobile Device sorry for the spelling. On phone.

Last edited by cr34t3d_by_d4rkd3n; 09-11-2011 at 07:10 AM.
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Old 09-11-2011, 07:10 AM   #9
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Re: What do you think ?

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Old 09-11-2011, 09:18 AM   #10
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Re: What do you think ?

How heavy is the boat that you pull? Do you have to really slip the clutch when pulling it out of the water? If it is heavy, I think that you would have problems if you just went to a highway gear and didnt swap to a transmission with a low first gear. Also, the great thing about our trucks is that there is plenty of room to swap in whatever you want and it is not that difficult.
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Old 09-11-2011, 10:21 AM   #11
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Re: What do you think ?

The boat is just 2100 pounds (Bass Tracker 18.9 foot)
The carb. is a rodchester 2 barrel
mostly city driving
the only highway driving is to the lake
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Old 09-11-2011, 10:44 AM   #12
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Re: What do you think ?

swap in a 700r4...cheap, overdrive, low first gear, and other than driveshaft length, there shouldn't be any problems to installing it.
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Old 09-11-2011, 11:14 AM   #13
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Re: What do you think ?

I would go with a higher gear rear end - 2.73 or 3.23 if you are concerned about towing. I would have someone experienced in differential work install it if you are not familiar with them. 700R4 would be next if you can afford it, but if it costs more than $500 to get it installed I would pass on it - city driving won't give you much benefit of overdrive on a 700R4.
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Old 09-11-2011, 12:20 PM   #14
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Re: What do you think ?

If you put a better intake, a 4 barrel carb with small primaries, and a set of headers with dual exhaust, you would improve performance and mileage. That would set you back several hundred dollars. I agree that if all your driving is around town, the 700r4 would provide less benefit.

Assemble good used parts as you can and you will get there sooner than you might think.
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Old 09-11-2011, 01:12 PM   #15
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Re: What do you think ?

You say it has low rear gears, but you don't sound as if you have confirmed what they are. Before you take anyone's advice on what to do, determine what ger ratio you actually have. If its 3.73 or lower, a gear swap to 3.42 or higher will get you about 1-2 MPG. If you can find a cheap axle with the gears you need, thats a pretty good trade up. If you have to buy new gears and possibly a 3 series carrier, then your not gaining much.

There is no doubt that swapping to a 4 or 5 speed stick would help. A 700r4 would be a good choice too if you prefer an auto. All of these would make your truck more efficient to drive and quieter as well. The cost might be a bit excessive for the gains in MPG so it's up to you to decide.

Check your gear ratio and tell us what you have.
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Old 09-11-2011, 11:48 PM   #16
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Re: What do you think ?

Quote:
Originally Posted by cr34t3d_by_d4rkd3n View Post
u can find a 1000doller parts truck. What rebult standard can u find for that? I have 311s and get 11mpg if i baby it. These trucks are square. To make it efficent is nearky impossible. Yes a 700r4 is the smartest thing. But forsomeone without a welder or oxysed torch installing a non factory transmisson is not is not cost effictive. If he.puts any taller gears in there all power is gone. Infact worse gpm is possibke due to more struggle to start after a stop. Sense the truck us a stock 6 shes got gears. To slam taller in there will indeed worsen the milage unless the car sees 75% highway. Cost effictive.
Posted via Mobile Device sorry for the spelling. On phone.
If he has a grand to spend on a parts truck, he can pick up a rebuilt 700 and be on his way. Not sure where the rebuilt standard comes into play, but ok. Proper tuning and the right total package, decent mileage can be obtained fairly easily. If he has access to a salvage yard, he doesn't need a torch or welder to swap in a 700. That's pretty much a "bolt in" swap, as much as I hate that term.
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Old 09-12-2011, 12:13 AM   #17
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Re: What do you think ?

A daily driver would like a NV3500. OD and nice gearing for every day driving.

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