Chevy 350, Vortec vs TBI

[greenjeep]

I'm finally dumping my AMC 360/TH400 and want to do a 350/700R4 set up, but have several questions.

I know it will bolt up, but is it a good idea to run a Vortec w/a 700? My hesitation on a 4L60 is that I want to run a reverse manual valve body and as far as I know they don't have them for a 4L60, right?

I currently have a TBI setup and am ignorant of a Vortec, how are they for reliability/ease of working on/trail fixes? A TBI is cheaper, but is the Vortec worth it?

What are the concerns on buying a used 700, I know the later ones are better. Or, I have a 700 which lost reverse, should I just pay the extra and rebuild that one since I'll have to pay someone to get in it to do the manual valve body anyway?

Anything else I need to know?

P.S. This will all be attached to my Dana 300 if that matters.

 

[Tacoma]

TBI is about as simple as they come, and very easy to fix/diagnose trailside. Probably 98% of the time, you won't have any issues at all.

Vortecs are a little more involved but not awful, the power increase is mostly due to better heads.

If it was me, It would probably come down to a couple things:
1. was is the price differential, because the power differential isn't big enough for me to care in a trail rig
2. how much work do I already have to do for this swap? IE: if you have to replace all the wiring, then any extra for the Vortec swap (and it's not much more than the TBI, but TBI is totally standalone), then have at it.

700r4/4L60 are the same transmission, the 4L60E has computer control. Either of them are fine behind any GM smallblock-- since that's where they were designed to be. I would prefer the 700r4/4L60, because ECM's can be fickle.
Make sure and set the TV cable properly on any of those 3 transmissions.

87-up 700's have an auxiliary valve body. You can see this on.. the.. driver's side? I think? of the transmission, it will have a curved parting line where they modified the casting mold. It's kind of a bumpout on the side.

I would rebuild the one you have and know for sure what went into it.


My $0.02, YMMV ... and get some %$#@$ shoulder belts!

 

[4554x4]

In my opinion, for a trail rig only, I would stick with the beefy turbo 400. I doubt you will ever really need the overdrive that you will get with the 700/4l60 trans.
I would find a chev turbo 400, it will fit your dana 300 without modifications.

I like the simplicity of the tbi over the vortec setup. I agree with Tacoma, the power is in the heads. I would probably use the vortec motor with a tbi intake and throttle body.
You already have all of the electronics on your 360, why not keep it simple?

Either setup will be fine, but I like them simple.

 

[Tacoma]

Totally ignored the 400-- just assumed you had your mind made up about the 700r4.

If you haven't, definitely consider keeping a 400. If yours is in good shape, the guts will swap right into a GM case. If you aren't driving on the road w/your Jeep, the OD of the 700r4 won't do you any good... and I don't think the lockup converter or the .50-lower first gear are worth much either.

Good point, Wayne.

 

[greenjeep]

My big reason for the swap is that coming home from the trail last weekend I lost all the forward gears in my 400. This is the 3rd 400 I've gone through in 10 years. So no go on using my guts.

While in Moab I don't trailer my CJ, so there's a huge attraction to overdrive to get to places like BFE or Gemini Bridges Rd. Plus 4-lo and 3rd gear is often too low on many of the between the obstacle stretches of trail. And I can't think a lower first gear is ever bad.

All pluses for a 700 IMHO.

 

[4554x4]

My big reason for the swap is that coming home from the trail last weekend I lost all the forward gears in my 400. This is the 3rd 400 I've gone through in 10 years. So no go on using my guts.

While in Moab I don't trailer my CJ, so there's a huge attraction to overdrive to get to places like BFE or Gemini Bridges Rd. Plus 4-lo and 3rd gear is often too low on many of the between the obstacle stretches of trail. And I can't think a lower first gear is ever bad.

All pluses for a 700 IMHO.

Good points Dave. So if you will be seeing some on road, the overdrive trans is a good idea. Have you considered a 4l80e? It is simular to the turbo 400 but with an overdrive. It has the same size output shaft as the 400 although the shaft is a little too long to bolt directly to your existing transfercase without a spacer. This isthe trans I use in my 74 chev pickup, with a spacer built by Sixb. The trans is about three inches longer than the 400, so rear driveshaft legnth may be an issue.

 

[Tacoma]

what are you doing for the controller on that 4L80?? Rebuild kits are pretty pricey for those, too, but then, so are the 700 kits.

I'm going to run a full manual kit in mine if I can find one that's totally non-electronic.

 

[Bart]

If you have a 700r4, just have it rebuilt heavy duty with the reverse manual valve body. I loved that set up in the Willys buggy. Also, with a reverse manual valve body you don't have the TV cable. BTW, if you decide to go with the 5.3 generation Chevy's the 700r4 will work with them also and no need for VSS.

 

[greenjeep]

If you have a 700r4, just have it rebuilt heavy duty with the reverse manual valve body. I loved that set up in the Willys buggy. Also, with a reverse manual valve body you don't have the TV cable. BTW, if you decide to go with the 5.3 generation Chevy's the 700r4 will work with them also and no need for VSS.

What's a reasonable price on rebuilding a 700?

I know nothing about a 5.3, educate me!

 

[RockChucker]

5.3's are the next generation GM small block that replaced the 350's. with a tune on the the computer, in stock form they are good for around 350 hp or so. Not that economy is a factor for you so much, but I hear guys with them are getting around 25 mpg if they drive conservatively. And it is pretty easy to find them in junkyards for $500 with the wiring harness and computer. Plus it is all the new technology, not that a TBI is bad, this is just better.

 

[greenjeep]

5.3's are the next generation GM small block that replaced the 350's. with a tune on the the computer, in stock form they are good for around 350 hp or so. Not that economy is a factor for you so much, but I hear guys with them are getting around 25 mpg if they drive conservatively. And it is pretty easy to find them in junkyards for $500 with the wiring harness and computer. Plus it is all the new technology, not that a TBI is bad, this is just better.

Cool, thanks!

 

[Bart]

Rockchucker explained it perfectly. BTW, there is one mounting bolt that is different on the 5.3 and the 700r4. Guess they wanted to make sure you were running the E tranny. I just ran without it and didn't have a problem. Again, that combo ONLY works with a manual valve body.

 

[Gravy]

I would look into a 5.3 or 6.0 just for fuel mileage alone. I don't love the mileage of my TPI350/7004 combo

 

[abhaulr1]

Im running a 97' 4.3 w/th350. Dana 300 stock gears rite now, 4:88's with 38 tsl. I get 17 city, 19 hwy. They put out around 200 hp stock. The 5.3 or 6.0 would be a better upgrade for more horse power. Just depends on what you want. 700r4 is going to run ya around 150-200 just for a good core. The rebuild kits that i have looked into is called, monster in a box. It comes with all the upgrades with the sprauge, corvette servo and good clutches.
Hope this helps.
Dwayne