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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: lpapa15 on October 04, 2010, 01:02:41 pm

Title: 79 street - 79 highway?
Post by: lpapa15 on October 04, 2010, 01:02:41 pm: I am planning on making my 79 4x4 k10 manual more highway adapted. I am going to swap my manual for an automatic. I was planning on going with a 400 tranny. What else would any of you recommend i do with my truck to increase the speed and drive on the freeway? axles? let me know.
Title: Re: 79 street - 79 highway?
Post by: jaredts on October 04, 2010, 01:08:00 pm: I don't know what axles you have now, but if you go with a 700R4 the overdrive might get you by with your current axles. If you stick with the TH400 plan you might want to change axles.
Title: Re: 79 street - 79 highway?
Post by: Lt.Del on October 04, 2010, 01:18:34 pm: are you saying a manual trans is not good for the highway? I would think it is better for the highway versus stop and go city traffic--wearing out your clutch and stuff.
Title: Re: 79 street - 79 highway?
Post by: lpapa15 on October 04, 2010, 01:32:52 pm: I agree with in town and the manual would be better but i cant take the shifting all the time around town and on the free way i am going 60 max. I need to get up to at least 70 without risking damage.
Title: Re: 79 street - 79 highway?
Post by: Grim 82 on October 04, 2010, 01:49:04 pm: What are you concerned about damaging? What kind of rpm does it run at highway speeds? If you are worried about causing engine damage because of excessive rpm I would look at switching the gear ratio. You probably have an SM465 in the truck right now, so if you swap in a TH400 your final drive rpm will be the same, since they are both 1:1. A 700r4 will give you the overdrive gear to drop rpm.
Title: Re: 79 street - 79 highway?
Post by: Lt.Del on October 04, 2010, 02:59:45 pm: i think you want an axle ratio change. Some 38 wheels will lower the rpms too on the highway ;D
Title: Re: 79 street - 79 highway?
Post by: Captkaos on October 04, 2010, 03:40:20 pm: We need more information?
What size tires?
Which manual? Granny Low 4 speed, 3 speed with overdrive?
What axle ratio?

If you are wanting to go faster on the highway change the rear gears.
Title: Re: 79 street - 79 highway?
Post by: VileZambonie on October 04, 2010, 04:31:14 pm: 700R4
Title: Re: 79 street - 79 highway?
Post by: Layne on October 05, 2010, 11:37:28 pm: Quote from: VileZambonie on October 04, 2010, 04:31:14 pm
700R4
Ditto
Title: Re: 79 street - 79 highway?
Post by: Lucky Jeff on October 10, 2010, 10:15:06 pm: Don't 700r4's have a number of problems?

I'm looking to swap my manual for an auto as well in the next week or so. Seems a 350 or 400 would be a lot more reliable.. I'd steer more towards a gear change with a 400 then anything else...
Title: Re: 79 street - 79 highway?
Post by: Layne on October 10, 2010, 10:18:00 pm: The early 700's had some issues 86 and newer is the way to go.
Title: Re: 79 street - 79 highway?
Post by: Captkaos on October 11, 2010, 08:30:59 pm: 88-92 had all of the latest updates, but by now unless it was original I would believe they would have been fixed by now.
Title: Re: 79 street - 79 highway?
Post by: lpapa15 on October 17, 2010, 02:22:49 am: I have a sm465. 4 speed with 1st being granny. Everything is original on the truck. I just want to be able to enjoy cruising on road or freeway. I am not concerned with going 90 mph i just want more comfort. The easiest transition will be better. I already know i will have to switch out the steering wheel and all the stuff with that but what else should i look for or do if I wanted to go this way? What do people usually do with the clutch arm in the cab when they switch over?
Title: Re: 79 street - 79 highway?
Post by: Layne on October 17, 2010, 03:29:17 am: It comes out with two bolts so you'll be ok
Title: Re: 79 street - 79 highway?
Post by: Grim 82 on October 17, 2010, 12:38:20 pm: You can swap columns or set up a floor shifter. You will need to patch the holes in the cab floor and possibly get some additional brackets to hook the auto trans up to your carb. Like Layne said, I just removed the two bolts holding the clutch pedal.

+1 for 700r4.