trans swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevy283 · 12-23-2004, 03:25 PM

a have a 1965 c10 283' a it has a stock manuel 3 speed i was wondering if a th350 auto would give me better mpg i have a 3.73 rear in it

60-66 Nut · 12-23-2004, 04:05 PM

Not likely, since the high gear in the 350 is 1:1 just like the 3spd, plus the convertor slippage could make it worse. You'd probably have to go to an overdrive to really help. A 700R4 would be just as easy to install as the TH350, you just need to run a hot wire for the lockup. Hope that helps.

60-66 Nut

zenish · 12-23-2004, 10:25 PM

the manual will give better mileage.you should change your rear gear,get a t5,get a three speed with overdrive if you can find one,or change to an overdrive automatic.

chevy283 · 12-23-2004, 07:04 PM

700r4 would give better mpg would a t5

chevy283 · 12-23-2004, 07:09 PM

there is a 1988 od 700re for sale for $250 is that a good price

60-66 Nut · 12-23-2004, 08:17 PM

A T5 would do OK also, but I think the 700 would be an easier install. Maybe someone who has done the T5 swap could tell you for sure. If that 700 is in good condition, that's a very good price, at least around here anyway. The 83-84 700's are not supposed to be quite as tough as the later ones, or so I have read.

60-66 Nut

Ed Cardinal · 01-02-2005, 09:07 AM

The 3.73 rear was the most comon in these trucks but I do not think you can just switch out the gears in that rear unless you plan on going the other way and making them steeper like a 4.11 rear or something. Otherwise I believe the pumpkin will not fit the milder gears in it. You would have to get another rear to do it. And then you would probably want to go around a 3.36 or 3.08 otherwise you will sacrifice too much power / torque.
Remember the 283 is a very high reving motor and will tolerate the steeper gears much better. Also if you are running a stock 2-barrel carb you will want to change it out for a small 4 barrel with vacuum secondaries. If you pick the right carb and set it up right it will give you better mpg and more power when you need it. Just don't STOMP on it all the time or it will defeat the purpose. And a 3.73 is actually a good configuration for that truck. I would probably just drop in a 700R4 trans if you want it to purrrr on the HWY in overdrive and give you better mpg. That would be the easiest swap..........Ed.

chevy283 · 01-02-2005, 01:27 PM

so i should replace the cab with a 4 barrel and trans with a 700r4 and i should get 17mgp?

zenish · 01-02-2005, 08:29 PM

a quadrajet four barrel will get better mileage than an aftermarket carb.

Ed Cardinal · 01-03-2005, 08:01 PM

I would probably swap out the carb first and see how that works. The quadrajet is a great carb and would work nicely if you get the smaller CFM one. Edelbrock makes new versions of them for a decent price. If they are set-up right and not over jetted they are truly the best for these trucks.
And if you can't find a stock manifold you can go with an Edlebrock performer (not the RPM model). Even if you have to paint it to make it look more stock. Then after all that see how it goes. Unless you are doing a lot of long trips that set-up should be fine. And if you decide to sell the old auto trans let me know..........Ed.

chevy283 · 01-03-2005, 10:36 PM

i don't have a auto its a manuel 3 on the tree

qksilver · 01-03-2005, 11:38 PM

a 200 overdrive would mean not having to cut the drive shaft and the trans yoke might even be the same. Plus they have better gearing for a smaller motor and don't use as much power either. You would still have to reposition the crossmember, add TV linkage and shift linkage

chevy283 · 01-03-2005, 11:55 PM

200r4? im new

chevy283 · 01-04-2005, 09:58 PM

is the 200 overdrive from a chevy?

zenish · 01-04-2005, 10:02 PM

some 200r4s only fit buicks,olds, and pontiacs.some are also drilled for chevs.

Blue Beard · 01-04-2005, 10:04 PM

Does the Trans mount have to be changed as well?

chevy283 · 01-04-2005, 10:59 PM

so it would be easer to just go with the 700r4

12-23-2004, 03:25 PM	#1
chevy283 Registered User Join Date: Dec 2004 Location: wilson oklahoma Posts: 367	trans swap a have a 1965 c10 283' a it has a stock manuel 3 speed i was wondering if a th350 auto would give me better mpg i have a 3.73 rear in it

12-23-2004, 04:05 PM	#2
60-66 Nut Professional Beer Tester Join Date: Aug 2004 Location: Louisiana Posts: 453	Not likely, since the high gear in the 350 is 1:1 just like the 3spd, plus the convertor slippage could make it worse. You'd probably have to go to an overdrive to really help. A 700R4 would be just as easy to install as the TH350, you just need to run a hot wire for the lockup. Hope that helps. 60-66 Nut __________________ 60 Ford F100 Custom Cab 61 Apache Short Fleetside 64 C10 Short Stepside 65 C80 409 V8 5spd(X-Firetruck) 83 GMC 350 Olds Diesel 85 GMC Short Bed 86 GMC Short Bed 90 GMC R3500 Crew Cab 92 GMC 1500

12-23-2004, 10:25 PM	#3
zenish Registered User Join Date: Aug 2003 Location: stallings,nc Posts: 401	the manual will give better mileage.you should change your rear gear,get a t5,get a three speed with overdrive if you can find one,or change to an overdrive automatic. __________________ 1964 c10 short step 1962 econoline van 1989 rs camaro 2006 yamaha vino 125 1975 goldwing

12-23-2004, 08:17 PM	#6
60-66 Nut Professional Beer Tester Join Date: Aug 2004 Location: Louisiana Posts: 453	A T5 would do OK also, but I think the 700 would be an easier install. Maybe someone who has done the T5 swap could tell you for sure. If that 700 is in good condition, that's a very good price, at least around here anyway. The 83-84 700's are not supposed to be quite as tough as the later ones, or so I have read. 60-66 Nut __________________ 60 Ford F100 Custom Cab 61 Apache Short Fleetside 64 C10 Short Stepside 65 C80 409 V8 5spd(X-Firetruck) 83 GMC 350 Olds Diesel 85 GMC Short Bed 86 GMC Short Bed 90 GMC R3500 Crew Cab 92 GMC 1500

01-02-2005, 08:29 PM	#9
zenish Registered User Join Date: Aug 2003 Location: stallings,nc Posts: 401	a quadrajet four barrel will get better mileage than an aftermarket carb. __________________ 1964 c10 short step 1962 econoline van 1989 rs camaro 2006 yamaha vino 125 1975 goldwing

12-23-2004, 07:04 PM	#4
chevy283 Registered User Join Date: Dec 2004 Location: wilson oklahoma Posts: 367	700r4 would give better mpg would a t5

12-23-2004, 07:09 PM	#5
chevy283 Registered User Join Date: Dec 2004 Location: wilson oklahoma Posts: 367	there is a 1988 od 700re for sale for $250 is that a good price

01-02-2005, 09:07 AM	#7
Ed Cardinal Registered User Join Date: Dec 2004 Posts: 8	The 3.73 rear was the most comon in these trucks but I do not think you can just switch out the gears in that rear unless you plan on going the other way and making them steeper like a 4.11 rear or something. Otherwise I believe the pumpkin will not fit the milder gears in it. You would have to get another rear to do it. And then you would probably want to go around a 3.36 or 3.08 otherwise you will sacrifice too much power / torque. Remember the 283 is a very high reving motor and will tolerate the steeper gears much better. Also if you are running a stock 2-barrel carb you will want to change it out for a small 4 barrel with vacuum secondaries. If you pick the right carb and set it up right it will give you better mpg and more power when you need it. Just don't STOMP on it all the time or it will defeat the purpose. And a 3.73 is actually a good configuration for that truck. I would probably just drop in a 700R4 trans if you want it to purrrr on the HWY in overdrive and give you better mpg. That would be the easiest swap..........Ed.

01-02-2005, 01:27 PM	#8
chevy283 Registered User Join Date: Dec 2004 Location: wilson oklahoma Posts: 367	so i should replace the cab with a 4 barrel and trans with a 700r4 and i should get 17mgp?

01-03-2005, 08:01 PM	#10
Ed Cardinal Registered User Join Date: Dec 2004 Posts: 8	MPG ques I would probably swap out the carb first and see how that works. The quadrajet is a great carb and would work nicely if you get the smaller CFM one. Edelbrock makes new versions of them for a decent price. If they are set-up right and not over jetted they are truly the best for these trucks. And if you can't find a stock manifold you can go with an Edlebrock performer (not the RPM model). Even if you have to paint it to make it look more stock. Then after all that see how it goes. Unless you are doing a lot of long trips that set-up should be fine. And if you decide to sell the old auto trans let me know..........Ed.

01-03-2005, 10:36 PM	#11
chevy283 Registered User Join Date: Dec 2004 Location: wilson oklahoma Posts: 367	i don't have a auto its a manuel 3 on the tree

01-03-2005, 11:38 PM	#12
qksilver Senior Member Join Date: Dec 2004 Location: Southern Pines NC Posts: 3,853	a 200 overdrive would mean not having to cut the drive shaft and the trans yoke might even be the same. Plus they have better gearing for a smaller motor and don't use as much power either. You would still have to reposition the crossmember, add TV linkage and shift linkage

01-03-2005, 11:55 PM	#13
chevy283 Registered User Join Date: Dec 2004 Location: wilson oklahoma Posts: 367	200r4? im new

01-04-2005, 09:58 PM	#14
chevy283 Registered User Join Date: Dec 2004 Location: wilson oklahoma Posts: 367	is the 200 overdrive from a chevy?

01-04-2005, 10:02 PM	#15
zenish Registered User Join Date: Aug 2003 Location: stallings,nc Posts: 401	some 200r4s only fit buicks,olds, and pontiacs.some are also drilled for chevs. __________________ 1964 c10 short step 1962 econoline van 1989 rs camaro 2006 yamaha vino 125 1975 goldwing



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01-04-2005, 10:04 PM	#16
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	Does the Trans mount have to be changed as well? __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

01-04-2005, 10:59 PM	#17
chevy283 Registered User Join Date: Dec 2004 Location: wilson oklahoma Posts: 367	so it would be easer to just go with the 700r4

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