Drivetrain swap HELP

[NewType72]

Alright I'll get right into it I need some advice on my current daily driver/long haul road trip vehicle (currently short trip)

First off I'll give the run down of what I currently have

72 C/10 2WD SWB

1: 350 SBC motor old block 60 over on it's last leg only produces maybe 280 HP
2: 350 Turbo Tranny freshly rebuilt with a shift kit very solid
3: 12 bolt short dog leggin rear end with ring and pinion howlin like a banshee

Secondly What I forsee in my final buildof this truck

1: 350/350HP ZZ4 or built long block I have (not concerned until next spring on swapping my old motor for this idea

2: 700R4 overdrive tranny with shift kit and high end innards (I will find a shell from a local auto parts graveyard from a late 80's-90's truck and have my shop completely gut it and rebuild it with new parts

3: Ford 9" rear end with posi and disc brakes (I have my eyes on a complete housing with axles and gearing and disc for about 200$ from a friend of mine have also heard that they may have made extr short versions of these and that they were 5x5 bolt pattern and this is supposedly it) If so I would swap out my old 12 bolt for this and get the correct freeway gearing and be on my way

4: Salvage my 12 bolt and put in a Eaton or Powertrax Posi with correct highway gearing and freshen up the whole setup and save the disc brake conversion for a later date

NOW here's the big question what am I better off doing ((money not an issue just time to make it I wanna do this right the first time)) and what is the better setup for what I want to have?? also what will I need to change to accomodate for the longer 700r4 moving the old crossmember out and replacing it with a tubular one from a company and also buying a new driveshaft to fit the setup? I plan to do just the tranny and rear end at this point so I can have those dialed in before a put in a fresh motor..

would be very appreciative of ANY helpful advice or pointing in a direction of a build on doing this swap thank you all

[Captainfab]

I would judt rebuilt the 12 bolt, and install the 700R4. You can also use your original trans crossmember with the 700R4. You'll just have to move it back and drill some holes. Unless of course you just want a tubular crossmember, but you'll have to drill holes for that as well..

[NewType72]

Originally Posted by Captainfab

I would judt rebuilt the 12 bolt, and install the 700R4. You can also use your original trans crossmember with the 700R4. You'll just have to move it back and drill some holes. Unless of course you just want a tubular crossmember, but you'll have to drill holes for that as well..

Well if I move the original trans crossmember back to drill holes will I run into a problem having the cab on? I plan on keeping the cab on as much as possible the bed I wouldnt mind lifting if needed but the cab would make things difficult. now I know the new 700R4 would be longer so would cutting my current driveline and re balancing it be the best option? or would ordering a new one to length be best? I just had my driveline blanced with new ends installed last year

[Captainfab]

Drilling the top holes for the crossmember with the cab on can be a challenge, but it is doable. One way is to drill the bottom holes first and then install the bolts. Then drill the top holes the best you can at a little bit of an angle. This is not the best way, but it will work. Another way is to drill the bottom holes first, and install just 3 bolts. Then with an extra long drill bit drill the upper holes, going thru the open hole on the bottom flange. Then alternately move the 3 bolts, so you can drill all 4 top holes.

Yes I would just have your current driveshafy shortened, once you get the trans installed and get an accurate length figured out. It is much less money to get a driveshaft shortened, than having a complete new one made.

Originally Posted by NewType72

Well if I move the original trans crossmember back to drill holes will I run into a problem having the cab on? I plan on keeping the cab on as much as possible the bed I wouldnt mind lifting if needed but the cab would make things difficult. now I know the new 700R4 would be longer so would cutting my current driveline and re balancing it be the best option? or would ordering a new one to length be best? I just had my driveline blanced with new ends installed last year

[NewType72]

Originally Posted by Captainfab

Drilling the top holes for the crossmember with the cab on can be a challenge, but it is doable. One way is to drill the bottom holes first and then install the bolts. Then drill the top holes the best you can at a little bit of an angle. This is not the best way, but it will work. Another way is to drill the bottom holes first, and install just 3 bolts. Then with an extra long drill bit drill the upper holes, going thru the open hole on the bottom flange. Then alternately move the 3 bolts, so you can drill all 4 top holes.

Yes I would just have your current driveshafy shortened, once you get the trans installed and get an accurate length figured out. It is much less money to get a driveshaft shortened, than having a complete new one made.

Sounds easy enough to do whats the best way to measure out where the new tranny will sit on the moved crossmember? and as for the 12 bolt I'm looking to do a posi in it but unsure of who to go with and would my 3:73's work better once i have the overdrive for highway drives? (everyone here does 75+ and I love my truck but she wont keep up with that all day long) Thanks for the info very helpful

[NewType72]

Thanks a ton for the help Cap'n I'm almost 90% sure on keeping the 12 bolt in and currently am shopping around for makin her a posi as well as the same gearing as I have now just need to make the money to afford the habit now

[NewType72]

also have you heard of any reviews on this supposedly they keep the original holes but the bar is arched back to catch the tranny mount in the correct spot??

http://bowlertransmissions.com/p/97/...r4-crossmember