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Which auto/v8 combo for my D300?

664 views 16 replies 4 participants last post by  BigHG 
#1 ·
I am thinking ahead to the next phase of my rock crawler build up. I will be going with an injected V8 and an automatic. I want to keep my D300 as I have just installed the 4:1 kit and HD output shaft. I don't want to spend money on adapters if there is a way around it. I am really auto tranny ignorant.

I am looking at the 350 or the 302. My preference is for a 302HO. (I am a Ford guy) I like the lighter weight and (H8 being correct)easier to keep cool than the Chevy 350 (Arizona summers). it really depends on what will match up.


Which autos will bolt to my D300? What tranny is best for this application?

Thanks

Craig
84 CJ7
BRC Lifetime Member
 
#3 ·
The C6 tranny is very tough, and would be an easy bolt up to the 5.0, but I dont know what would be involved in adapting the D300.
The 727 as Brad mentioned is legendary in terms of strength and reliability. The 350 auto is also a great choice especialy if you use an FI SBC engine. The 350 auto, or 700R4 have probably the most options for electronic lock up and shift control.

Jeff
89 YJ
(sensibly altered for occasional off road use)
Vision without Action, is a Daydream. Action without Vision is a Nightmare.
 
#5 ·
(edit) this was my response to Brad, It didn't post the first time.

Ok, but then I need to inject it. It is not so much that I want to keep costs down, who doesn't, I just don't want to spend money on adapters. This is what I am thinking:

I have enough money into this D300 (which is still at Teraflex by the way) that spending money for an adapter would put me into the cost range of an Atlas. Rather than buy the adapter, I would just sell my D300 and purchase the atlas. Assuming of course that the auto of choice would bolt right up to an atlas.






Craig
84 CJ7
BRC Lifetime Member
 
#6 ·
The D300 and the Atlas II inputs are the same.
The advantage of the SBC or the 5.0 is the glut of aftermarket parts, and resulting affordability. Also the ease of locating low mileage, affordable engines, for the original swap or in the case of needing a replacement.

Jeff
89 YJ
(sensibly altered for occasional off road use)
Vision without Action, is a Daydream. Action without Vision is a Nightmare.
 
#7 ·
Is the electronic lockup that important. I would love it for those loose downhills. But can't I acomplish the same thing with with a low stall speed torque converter?

Actually, now that I have said that, I don't think I understand the concept of stall speed. /wwwthreads_images/icons/tongue.gif

Craig
84 CJ7
BRC Lifetime Member
 
#8 ·
A low stall speed will allow the torque converter, to lock up at low speeds. Being locked up means it wont be slipping causing excessive heating. Being locked up also means that trying to stop it at low speeds is nearly impossible. I wheeled with Troy Faber and his Sniper last weekend, he has to have additional brake boosters in the rear fender wells, just to try to stop that rig when its locked up at low speeds. By using an electronic lock up, you can run a higher stall speed, but lock up the converter electronicaly when you need to, and unlock it when you need more control on a slow climb.

Jeff
89 YJ
(sensibly altered for occasional off road use)
Vision without Action, is a Daydream. Action without Vision is a Nightmare.
 
#9 ·
I would`nt touch that 700R4 with a 10,000 foot pole . It`s a POS . I have had my dealings with that tranny in my Z71 , and I am one who actually changes my auto tranny oil as recommended .Just start asking questions about that tranny on the Chev boards , if they are honest they will tell you to avoid it to . Out of our small shift at work 4 guys run 90`s 4x4 Chevies , everyone of them has had auto transmission failure before thier 60,000 mile service . C6 all the way !!



Jeff /wwwthreads_images/icons/cool.gif
 
#10 ·
I agree the 700R4 is a total POS. I bought brand new blazers in 83 and 85, and ended having to sue GM because of the disposable trannies. I couldnt get through any summer of towing our race boats without replacing at least 2 trannies. But there are some good high dollar versions of the 700R4 nowadays. That gives you the electronic shifting, electronic lock up, and an overdrive. It wouldnt be my 1st choice, but it is a very good set up, in the right configuration.

Jeff
89 YJ
(sensibly altered for occasional off road use)
Vision without Action, is a Daydream. Action without Vision is a Nightmare.
 
#11 ·
So what are the options to electronically lock up the torque converter? Is this a function of the transmission or could I use a 727 or c6 with a different torque converter that I could switch?

Craig
84 CJ7
BRC Lifetime Member
 
#12 ·
Ive given ya about everything Ive got on autos.

Jeff
89 YJ
(sensibly altered for occasional off road use)
Vision without Action, is a Daydream. Action without Vision is a Nightmare.
 
G
#13 ·
My personal choice, and what I had is a 350/TH350. The only other choice I would seriously consider (unless I got a killer deal on something else) is a 350/TH400 combo. I like Fords too, but the Chevy 350 is just a beautifully simple, powerful, and reliable power plant.

 
#14 ·
LOL, it is appreciated H8. Now that your taking the rig full competition do you have any plans to changee to auto?


Craig
84 CJ7
BRC Lifetime Member
 
#15 ·
No slush box me. My 3rd gear low is just like an automatic, with the HP I have available. I can lope along at 500rpm(38:1= walking speed) or launch it up to 3700 rpm, in half a second, to reach escape velocities neccessary sometimes. I can shift through the gears nearly as quick as an auto. And I dont have to fight with low speed braking control. They both have their advantages, but I like my 4 speed.

Jeff
89 YJ
(sensibly altered for occasional off road use)
Vision without Action, is a Daydream. Action without Vision is a Nightmare.
 
#16 ·
Jeff

My record was 2 - 700R4`s in one week in my Z71 . Original blew while picking my daughter up right before our holidays(50,000 miles on it) . I got back with rental truck and picked up my truck at the end of the week and never even made it home with the rebuilt .
And those crooks at GM pulled off the wire under the 4x4 shifter(during 3rd tranny install) , the one that actuates the front diff. So after the 3rd tranny was installed I went to rescue my bud who is stuck up this Mtn. and no 4x4 . I took it back the next day and they TRIED to charge me $ 275.00 in labour for hooking up the wire they yanked off while re&reing the tranny .I`m usually as cool as ever but I really blew a fuse that day and the manager ended up tearing up the bill . Never again any GM products for me !! Sorry , it stills bugs me to this day .



Jeff /wwwthreads_images/icons/cool.gif
 
#17 ·
Ok, getting back to my subject. I always thought the Atlas was available with a few different input configurations. That not being the case my reason for not wanting an adaptor are moot.

What ford trannies are available that will fit the 302, have the tc lockup and be good swap candidates?

Craig
84 CJ7
BRC Lifetime Member
 
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