Need help on a new purchase

[Coleman]

Here's my ultimate goal, I want a (67-72) 4x4 that will be able to handle the occasional off road and the ablility to get there at reasonable speeds on the highway. Add in disk breaks, PS and possibly air conditioning as a bonus.
I currently have a 68 K20, SM465, Rockwell 221T. The SM465 is starting to go out, getting tight and tough to shift. I've run across a 72 K20, cheyenne super? with a 350/TH350 and np205 with PS, PB, air for 1000$. It runs but the TH350 is junk. It needs the usual rockers and one cab corner. Looks like someone puttied up the rain gutter over the windsheild but I can't really tell. It has the utility box instead of the regular long bed but I can swap that out. I can do all kinds of combinations between the two trucks to make up one decent truck except the tranny. I would really like an overdrive so I can get decent speeds on the hwy. I guess the question is, should I wait and find an 80's K20 to get my front disks and 700r4 for the 68, or do this 700r4 conversion on the 72 which has everything else, or just put in a rebuilt TH350 back in the 72 and put up with the high rpms on the hwy. My guess is the sm465 (4 speed granny) and the TH350 are going to be the same hwy rpms (sorry, haven't had time for pics)

[wanted]

If you go with 35 inch tires your truck will cruise down the highway nicely with the th350, assuming you have 4.10 ratio. I have 33 inch and its marginal. A friend has 35's and its noticeable better. I've heard the 700r4 is tricky to get correct gear and tire size combo to use the OD

['68OrangeSunshine]

Cole, I have heard the th200R4 is a beefier tranny than the 700R4. 700's are always in the shop. 200's are not as popular and can be had cheaper in the junkyards. I'm no expert on auto trannies, however.

[special-K]

When going to 35"tires on a 3/4t truck with 4.10s which would have had 7.50x16s(235/85s)from the factory,you will be right at 3.73s.I did this and run a 4L80E and the gearing is ideal.The results will be the same with a 700r4.If you want it to have the same pull as stock,you can go to 4.56s.This would be like 4.10s and you`ll have o/d.This is what I planned to do,but didn`t because I`m happy enough with the performance on/off road.I am running a NP241 with 4:1 low,also.

[1969 GMC]

Originally Posted by special-K

When going to 35"tires on a 3/4t truck with 4.10s which would have had 7.50x16s(235/85s)from the factory,you will be right at 3.73s.I did this and run a 4L80E and the gearing is ideal.The results will be the same with a 700r4.If you want it to have the same pull as stock,you can go to 4.56s.This would be like 4.10s and you`ll have o/d.This is what I planned to do,but didn`t because I`m happy enough with the performance on/off road.I am running a NP241 with 4:1 low,also.

o/t, where did you get a 4:1 kit for a 241?

[special-K]

Uhm,I dunno.What are they?I must have remembered wrong.I know they`re a much lower ratio.I stand corrected.

[1969 GMC]

ohh. they are 2.72:1 stock

there WAS a rumor about a 4:1 kit for them, though, thats why I asked.

[Coleman]

Well the purchase became reality. As I said, I "was" going to pull the front clip off the 68 and build everything on the 72 platform but the 68 is all original, numbers matching and such. Now I'm looking for a 67 front clip to match the box I have and end up with 2 projects. I will end up going to an OD trans for the 72 someday, probably a 200R4 since it is a straight swap for the TH350. Here are some pics so far..

[special-K]

Ohh,the`68 is a 4wd.Good move saving it.With your decision you have become a certified truck junky and there`s no going back.We are all here to help one another through.If I was closer(alot closer),I`d help take that utility body off you hands.I`m building a b/a work truck project.

[Coleman]

Yep, I'm getting close to peddling a 72 front clip and the Utility box. A member has a 67 front clip I'm picking up tomorrow so things are coming together. Anyone know if the rad support for the 72 will work for the 67 front clip. It wouldn't suprise me if they are different but I would like to just bolt the 67 clip on the existing 72 rad support. Any ideas?

['68OrangeSunshine]

Cole, I think the rad supports are the same. I have a disembodied '72 support in my parts pile for the " '72 phantom of the junkyard" project. You could take a look. Been too busy to copy the email lately, working on the gem show, but I'm off til Weds.

[gator2511]

I put a th400 in my 72 4x4 for strength. Then I added a G/V overdrive to bring down the highway rpms. Turn off the od in the woods and click it on for the highway. At 70mph it turns around 2200 rpms. Just another idea for you.