Thanks in advance! I'll try and make this as short and complete as possible. 77 chev 3/4 ton lwb p/u, came stock w 400sb, turbo 350 tranny and NP 205 transfer case. Ordered a new GM crate motor HT383, seppentine belt kit etc and an Art Carr built 700r4 tranny, shipped to local GM dealer for install, having neither the time or equip necessary for good job and quick turn around. (big mistake) Anyhow 4-5 months later and many horror stories truck is returned to me at least mobile, running fair. Very poor gas mileage 5-6mpg usually best ever about 9-10, got better mileage and pulled better before the new motor and tranny; motor seems to run strong after I got a smaller carb on it and leaned it out somewhat, they spec'd a much to large carb for it; has always felt like the tranny has not been engaging properly felt slippy at some rpms or when pulling a load, have put about 2K miles on it mostly to work and back less than 3 miles a day, played with the cable adjustments for some improvement at times, never felt "right" though. Was definately clunky and then slippy under acceleration in reverse. Today out of the blue no reverse-slight pull at idle, any throttle =s no go. Art Cars shop in in CA and phone support has been minimal at best, I live out in the sticks of eastern UT. I don't know any good old fashioned mechanics or tranny guys here.

Two Questions.
1. Any ideas about the auto trans

2. How feasible and expensive would it be to dump the auto and put a 4 or 5 speed manual in it? As in what tranny should I consider, are the pedal assemblies readily available and installable without a lot of fabrication work.
I'll have many more questions about this option if this seems to be the way to go. Thanks again for your time.  

WOW, sounds like the mechanics at that dealer don't know how to truely tune an engine.

What carb did they put on it and what did you go with?

What is the gear ratio in your axles and what size tires do you have?

Do you have any idea what the ignition timing is at?  Did you have a new HEI distributor put in or did you have your old one installed?

Answer these and I will give you the best answers that I can.  

This is one example of how bad the mechs were at the dealership. The motor came with a h2o pump as did the serpantine belt kit as it turns in the opposite direction. We talked about this fact as the parts were all arriving. They left the motor h2o pump on and put the kit on and called and said it was ready I picked it up drove home opened the hood to check it all out and went dang thats hot! Looked at it, started it again and lo and behold the fan was pushing air out the front of the vehicle. I am no genius wrench but am not a complete idiot either. They were. And this was at a GM dealership. Initially they put a holley 850 in jetted for sea level, we are at 5600 ft. now a holley 650 supposedly jetted for our altitude is now residing in place, in the rear 4:11 with 35" 12.50 16.5  BFG mud terrains unsure about the front pumpkin what ever was stock with the truck it is a 3/4 ton camper special. 10 bolt front diff 14 bolt corporate rear w floating axles. As to the timing I got fed up with the dealer and took it to a different shop who said that the timing had been way off and the vacuum lines were not run properly. after I got it back from them it did run much better but they could not figure out the tranny. I do not know what degree advance etc that they set it at, the engine feels strong and does not appear to be running rich. Heat noise or knock has not been an issue so I do not think it is to lean. New Mallory HEI installed w new wires etc. A couple years prior to this I did a sheet metal off resto, had just the frame with drive train in one stall and the sheetmetal cab and bed in the other. New fuel lines, gas tanks, axle joints, u joints, brake lines, brakes, A/C stuff, etc etc. Motor only had about 102K miles on it before the drivetrain swap, ran well, a little tired. figured a new motor and 4 speed auto tran would bump up the juice and maybe give me better mpg or at least equivelant. Was originally full time fwd but had been converted with Warn Hubs and a Doug Nash tranny kit in the old turbo 350. So now the question becomes, go through the old 350 turbo reinstall and get new drive lines-(trannies were different length, had to move the crossmember and inch or so, got new one or ones then and they did not return the old ones); dealership has since changed hands as well. Or put a manual in which I would love to do but will come down to price and finding someone I feel confident enough in to allow them to do it. On top of which the wife need a new ride and am putting a new h20 pump, timing belt and stuff on the kids car. It is truly vehicle hell at the moment. Thanks for your response. Ray

edit: 4" all spring lift  

Unbelievable the lack of knowledge that some so called mechanics have.

It sounds like your engine is running fine now.  I hope you have changed to the reverse rotation water pump and fan.

For the transmission, it is possible that it is already toast.  The 700R4 has a .70 over drive and 4.11 gears (it should be 4.10 gears, isn't your ring and pinion 41/10 in the 14 bolt FF) with 35" tires is too tall a ratio.  The converter rides stall all the time and cooks the transmission in a short time.  With 35" tires and 4.10 or 4.11 gears your engine would be turning 1663 RPM at 60 MPH in over drive in converter lock up.  That is too low of RPM for converter lock up to hold.  You should be running 4.88 gears for the 700R4 with 35" tires; then in over drive the engine would be turning 1979 RPM at 60 MPH.  The TH350 is 1:1 in 3rd gear and was turning the engine at 2375 RPM at 60 MPH with the same gears and tires, the same as the 700R4 in 3rd gear except that the 700R4 would have a hard time holding converter lock up.  If you have a tach you can see the RPM difference from converter stall to lock up, or if the exhaust is loud enough you can hear it.

You could put the TH350 back in or have the 700R4 rebuilt or replaced and change to 4.88 gears.  Have the current 700R4 checked out before changing out.  

Thanks. Yes the proper pump and fan were installed. So ya think the TH 350 will be solid as is? I put a lot of miles on it with that wheel gearing combo prior to the motor/tranny swap. Seemed to have no problems. Yes, I would have it gone through and everything flushed prior to reinstall. I'll talk to a shop this week and see what they think. I will also try and find out what speed stall converter came with the 700r4 tranny, I suppose if it was a higher rpm than stock that would necessitate an even lower ratio ring and pinion correct? I'll try and get it in this week, have the r4 looked at get an estimate for going both ways and go from there. I'll keep ya updated as things progress. Thanks again and if ya have any more suggestions or thoughts send them my way. Thanks, Ray

It could be 4:10 I could'nt find the original window option sheet which I still have somewhere, it was one or the other.  

You should, DEFINITELY, consider a law-suit! Make them hire some good mechanics- from another shop- and fix their screw-ups.

I hate to say it but sounds like they murdered your (should have been) radically fantastic set-up.  

raebear:
Thanks. Yes the proper pump and fan were installed. So ya think the TH 350 will be solid as is? I put a lot of miles on it with that wheel gearing combo prior to the motor/tranny swap. Seemed to have no problems. Yes, I would have it gone through and everything flushed prior to reinstall. I'll talk to a shop this week and see what they think. I will also try and find out what speed stall converter came with the 700r4 tranny, I suppose if it was a higher rpm than stock that would necessitate an even lower ratio ring and pinion correct? I'll try and get it in this week, have the r4 looked at get an estimate for going both ways and go from there. I'll keep ya updated as things progress. Thanks again and if ya have any more suggestions or thoughts send them my way. Thanks, Ray

It could be 4:10 I could'nt find the original window option sheet which I still have somewhere, it was one or the other.

I think you are missing the point here. A 4.10 is way too tall for your setup and the OD tranny makes it worse. You wind up riding the torque converter stall a lot and slow bake the tranny and also get poor MPG too. If you simple drove with it in drive/3 you would basically have a THM350 with a deeper first and second gear. To put this into further perspective, even if you had 5.13 gears and a 700R4 you would have a lower cruise RPM at 65MPH than a THM 350 with 4.10's. (approx 2200 vs 2600 RPM) Furthermore, your overall effective gear ratio in first with a THM 350 and a4.10 is 10.3 to 1 vs 15.8 to one with 700R4 and 5.13's.When hooked up to properly geared axles, a 700R4 is a excellent tranny. One that fail is because axle ratios are too tall and they fry them using OD. The real beauty of a 700R4 is that it lets you run some serious gears like 4.88's and 5.13's for good power on and off road and yet cruise nicely too.