90 YJ to SBC 350/T400

[YouCanDoIt]

:agree: ok...I can't take the 4banger any longer...BYE..BYE.. 170k miles..time to go...
I am going to install a SBC 350/T400 transmission.. :twisted:
I have done alot of research on this and have found this to be the best swap.
I am going to go with the fuel injected, so i don't have to screw with it later, and the guys in I am looking at motor from will only be a $100 difference. The wiring will cost a little more,,,NOT going to tackle that myself..A little out of my league. I am looking at a pair of DANA 60'z to replace the stock axles and considering dropping the axles under the springs to gain a few inchs...(any negatives to this) ..... so far with all my research I am looking at $1000..without the wiring, t-case, wheels/tires (from 5 to 6 lug), radiator, motor mounts........SO with all that said...LET the advice begin...any experience in this conversion WILL be greatly appericiated... along with anything I have over looked thus far.........

 

[Itchee96]

Good Luck?

 

[redrooster]

$1000 for what then? That can't include the axles you mentioned. A front 60 will be $1000 or more by itself. Buy your front 60 complete, because the brake parts and spindles and such will eat you alive if you have to replace them.
I wouldn't spend more than $500 on a complete throttle body 350, because around here you can get a more powerful, modern, port injected 5.3 for $700. Also, GM hasn't made the TBI 350 in over 10 years, so are you going to have to rebuild a high mileage engine? Furthermore, the salveage yard I bought my engine from offered a 90 day replacement warranty. Ask about that.
I would expect to pay $400 to $500 for a TH 400 bench build (meaning you pull it and merely drop off the transmission). I would not recommend installing a used automatic transmission without rebuilding it first. It's just not worth the headache you will encounter later.
You will also have to consider the following: wiring harness, ECM programming, gauges, conversion radiator, motor mounts, transmission/t-case mounts, which transfer case and any adapters and driveshafts. That's probably over $2000 all without doing the ton axles and a spring over lift.
I'm not trying to discourage you, but your budget is too low.

BTW... there are two words that don't belong in the same conversation...the words Jeep and Budget. You can quote me on that.

 

[redrooster]

If that's the way you want to go:
eBay Motors: Chevrolet : C/K Pickup 3500 (item 170208598260 end time Apr-13-08 17:32:28 PDT)

 

[jps4jeep]

question, why a TH400?

TH350 is smaller and can handle a build 350 ci just fine, or if you want the over drive, 700R4 or 4L60E (basically the same, latter is electronic controled)

 

[jps4jeep]

wait a tick.. under $1000 and 6 lug D60's. the dynatrac conversion hubs along const $1000



I agree with rooster, but will add, build it right the first time, cause the second and third just get more expensive.

 

[YouCanDoIt]

AWESOME!!!! I like all the info...YOU guys are great...
1st: I must be gettting the deal of a life time on the axles but YES I found them in a junk yard on a 88 wagoneer,, 6 lug complete... $100 each hub-hub...I have to pull them...I had a buddy check them out with me, and they look and turn good... going to pull them this next weekend.
2nd: I am not 100pct set on the T400 transmission, that is what a friend recommended.....the 700R4 I do not want though,,had one in a Suburban, dang thing gave me hell...I heard certain yrs of that transmission had some issues, i must have had one of those..
3rd: I have looked at a dozen engines and have found several in a few different junk yards, one in paticular offers the 90 warranty and is willing to start any of them on the spot.

Any opinions on the spring over change,, I know that will entail alot more work but, during the engine swap, wouldn't that be the best time to do it as well, since the axles will be out anyway.

 

[redrooster]

My friend, you have a lot of research to do before starting a project of this magnitude.
Dana 60's never came in wagoneers. They are likely Dana 44's or Dana 44 front with model 20 rear. Either way they are not a very popular swap.
The TH400 is a great transmission and I also run one, but unless you are going to flog it every weekend with a 300+ hp torque monster, you will likely be happy with a TH350. The TH350 will handle the hp, but need extra support at the tailhousing and a seperate transfer case mount to take some of the load off the tailhousing. I have seen several Th350 cases crack at the tailhousing due to improper support. I haven't seen many burn up. I have three friends who run them in LS1 powered buggies with no issues. Just add that extra mount and rock on.

 

[jfrabat]

Any opinions on the spring over change,, I know that will entail alot more work but, during the engine swap, wouldn't that be the best time to do it as well, since the axles will be out anyway.

I did A LOT of research for this, as I was gonna do it myself. There are MANY advantages of a SOA conversion, including:

The most flex for a lift this high
Stock ride is maintained
Perfect lift to clear 35"
You can do a over-the-top steering and get the steering out of harms way

However, to do it right, you will need to do some fabrication. You will need a SYE and new DS (you probably already got that, though). Then you will need the spring perches removed, and new ones installed in the right place (above). You will need to extend and/or re-route the brake lines, vacuum lines (if you are still using the axle disconnect) and vent lines (you also have to do this with a regular lift) to avoid them getting damage when at full flex. You will need to change your shocks, and probably will need to relocate the shock mount on the axle to a higher position (also good for avoiding damage!). It also involves loosing your track bar (or replace it with an adjustable one, but if you are going with the SOA, its because you want the most flex, so I am guessing you will ditch the bar) and using a dropped pitman (unless you use the JKS trackbar, which would then require you to use the stock pitman to keep the track bar and the link parallel).

But you will also need to use a trackbar to avoid axle warp, which is the biggest issue. I have heard that it is best to fabricate your own here, but there are some commercially available. I remember Rocky Road Outfitters made a pretty complete kit for a SOA conversion that I almost got, but went with the RE 4" lift instead because of budget restrictions (yeah, I know, BUdget and Jeep dont go well in the same sentence). Rocky Road also had the OTT steering package available.

Anyway, I still like the idea of a SOA, and if I could have afforded it, I would have gone in this direction...

Hope this helps!

 

[redrooster]

The engine swap would be a lot easier to do with the axles and tires on the Jeep. Do the axles after the engine and transmission conversion.