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#1 |
Account Suspended
Join Date: Mar 2014
Location: Aquashicola PA
Posts: 143
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'67 250 w/3 speed convert to auto trans...???
So at some point I'd like to swap in an automatic Behind my 250 C10. What transmission would be a good choice? What are some of the not so obvious things I need to know and/or buy? Thanks for any help.
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#2 |
Registered User
Join Date: Dec 2011
Location: winnipeg
Posts: 1,107
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Re: '67 250 w/3 speed convert to auto trans...???
Turbo 350 would be my choice.
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#3 |
Registered User
Join Date: Jun 2013
Location: Brant Lake New York
Posts: 224
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Re: '67 250 w/3 speed convert to auto trans...???
You will find that across the web on many diffrent sites that this debate of TH350 vs TH400 rages on.. from my research most people will say that the TH400 is heavier and bulletproof, that it is a better tranny to have if you have big block or plan on breaking 500hp.. with your 250CI the 350 would be perfect as it is said it should not take as much to turn it.
when I found my GMC I was a little disspointed that it did not have a V-8 but very happy that it had a TH400... I now love my 250CI and the improvments I have made to it and glad it is mated up to a bulletproof tranny. If I was you I would see what I can find locally and if you can grab a nice well taken care of tranny for a good price, thats the one I would take, whether it be a TH350 or a TH400
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68 GMC 2500 stepside LWB 250CI |
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#4 |
Registered User
![]() Join Date: Dec 2012
Location: Chandler AZ
Posts: 1,149
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Re: '67 250 w/3 speed convert to auto trans...???
200 4r would be my choice depending on tail gears. You'll get out of the hole better and cruise better as well.
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1970 Longhorn, Front Disc, 350/4 bolt, 882 heads, HEI, Edelbrock, 700R4, HO-52/4.11. 1996 Corvette, Collector Roadster, LT4, 396, 450RWHP, 6sp, 4.11/Dana44/posi 5 point roll bar And let us not grow weary of doing good, for in due season we will reap, if we do not give up. Gal 6:9 |
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#5 |
Registered User
Join Date: Dec 2011
Location: winnipeg
Posts: 1,107
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Re: '67 250 w/3 speed convert to auto trans...???
The only reason I did not recomend an od trans is that idk if there is a way to make the very important tv cable operate correctly with the inline 6. If there is I would use that for reasons you stated as well.
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#6 |
Account Suspended
Join Date: Mar 2014
Location: Aquashicola PA
Posts: 143
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Re: '67 250 w/3 speed convert to auto trans...???
So with a TH350 you don't need a kick down cable? What about crossmember and drive shaft length. I currently have an SM420.
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#7 |
Registered User
Join Date: Dec 2011
Location: winnipeg
Posts: 1,107
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Re: '67 250 w/3 speed convert to auto trans...???
Yes and no. You can run without one but you have to shift down for passing etc. also the turbo 350 was used behind inline sixes so they have the correct bracket for the cable. A 700r has a tv cable that is very sensitive to adjust and controls the way the trans shifts by altering line pressure.
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#8 |
Account Suspended
Join Date: Mar 2014
Location: Aquashicola PA
Posts: 143
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Re: '67 250 w/3 speed convert to auto trans...???
Ok I got ya. I'd put a lokar or similar floor shifter on it anyway so I could live with knocking it down to pass. Or if that didn't go well I could hook up the cable. I dealt with a TV cable on a jeep so I know how sensitive they are.
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#9 |
Registered User
Join Date: Feb 2007
Location: west coast
Posts: 3,374
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Re: '67 250 w/3 speed convert to auto trans...???
More than likely, you have the standard 3.73 ratio, so an overdriveauto is probably most desireable trans in todays world of higher speed limits. Unfortunately, there is no TV kit for auto overdrives engineered precisely for the 6 cyl. available. When will the aftermarket suppliers help us out on this? As far as I know, you have to fab one up on your own. Its possible someone on a NOVA site came up with a system, the majority of early Novas were built with 6 cyl engines.
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#10 |
Account Suspended
Join Date: Mar 2014
Location: Aquashicola PA
Posts: 143
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Re: '67 250 w/3 speed convert to auto trans...???
I don't think over drive is a necessity for me. What am I looking at otherwise? Crossmember, driveshaft etc if I go with a turbo 350?
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#11 |
Senior Member
![]() Join Date: Sep 2007
Location: Albuquerque NM
Posts: 7,848
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Re: '67 250 w/3 speed convert to auto trans...???
Youre going to need a good grinder and cut off wheel and a bfh to take out the manual tranny crossmember. Thats where im at now on my 67
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1967custom |
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#12 |
Account Suspended
Join Date: Mar 2014
Location: Aquashicola PA
Posts: 143
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Re: '67 250 w/3 speed convert to auto trans...???
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