Th400 to 700r4 ????

[HotRodPC]

Hey HR, he said he was turning 3300 on 35's, not the factory size.

He must be running 4.56's then.

 

[HotRodPC]

Well the nv3500, nv4500(including bell and tcase adapter) and th400 are all extremely close in legnth if not the same so driveshafts should not be affected

Yep, if they're the same to that point, then they sure should all share the same driveshafts. That's one thiing I love about GM. They do make things universal. I bet someone could pick up an NV3500 pretty cheap. They are no slouch either. I'm not real fond of the internal slave cylinder, but they do work fairly well and not near as strong as an NV4500, but they'll get the job done. I woudln't be afraid of an NV3500 in a 3/4 ton if I wasn't doing any mega weight towing with it. They actually have close ratio's than the NVV4500 too since NV4500 has the compound granny low. There is a benefit to that in the NV3500 for wheeling. Close ratios are important in wheeling rigs.

 

[Driver4r]

He must be running 4.56's then.

Now we agree

 

[HotRodPC]

Now we agree

If he is, I like 4.56's even better with an OD trans. Even with 31 in tires. Got the good low end take off torque, plenty of towing power and taking strain off your drivetrain, including, trans, clutch, driveshafts, Tcase, U joints and all. 4.56 with an OD trans it best all around combo IMO. However, I do not think it's worth the cost of a gear change to go from 4.10's to 4.56's so that makes the 4.10's the more reasonable choice since they're much more common in the 3/4 and 1 tons.

 

[Driver4r]

If he is, I like 4.56's even better with an OD trans. Even with 31 in tires. Got the good low end take off torque, plenty of towing power and taking strain off your drivetrain, including, trans, clutch, driveshafts, Tcase, U joints and all. 4.56 with an OD trans it best all around combo IMO. However, I do not think it's worth the cost of a gear change to go from 4.10's to 4.56's so that makes the 4.10's the more reasonable choice since they're much more common in the 3/4 and 1 tons.

4.56's with 35's would be ok, but i wouldnt want to run 4.56's with my 32's. I dont know how well a stock 305/350 would do turning that fast going down the highway, especally if you kick it down into 2nd. Think of how fast that engine would have to rap up to roll the tires fast enough to pass a vehicle.

 

[HotRodPC]

4.56's with 35's would be ok, but i wouldnt want to run 4.56's with my 32's. I dont know how well a stock 305/350 would do turning that fast going down the highway, especally if you kick it down into 2nd. Think of how fast that engine would have to rap up to roll the tires fast enough to pass a vehicle.

No problem at all. You wouldn't need 2nd with 4.56's, you'd have plenty of torque in 3rd at 50mph or more, this is the whole reason you go lower gear and have OD to compensate it. And why worry about rpms on a Small Block Chevy? SBC's love rpm and beg for more. the only limiting factor up to about 6,000 rpm is your cam and valve springs or you'd be floating valves. The last good motor I built didn't float valves until 7800-7900 rpm, and that was a 2 bolt main cast iron crank 350. Very well balanced and put together I will add. Rods were worked over, tolerances were tight, chromolly ARP rod bolts, dual springs and dampners in the valves, guide plates and all that good ****. I'd rap it to 7800-7900, but It was shifted at 6800-7200 rpm, usually right around 7000. Yup it was a bigtime rough idler. I forget all the cam specs now but it was a .525 lift cam IIRC. That's pretty big for a SBC.

 

[Chaz]

Ive got the same problem,,,89 burb 350 th400 on 35's runnin bout 3000-3100 rmp at 65mph,,,,I've been strongly considering a 4L80E swap out of a 91,,,,,but I'd absolutely love to have a manual trans,,,,I thought a manual trans swap would be mor difficult than an automatic to automatic,,,,can you tell me would a NV3500 bolt right up to my NP241 transfer case without driveshaft mods,,,,,???? If thats the case im gonna start lookin for the manual I really dont want to screw around wit all the electronic garbage,,,what bout my speedo,,,,I shold be able to run the speedo cable from the manual trans rigth to my speedo too right,,,,??? Thats bitchn,,,im gonna start lookin into that manual swap,,,,

 

[Chaz]

Oh yeah and its my daily driver too,,,,,,got 4 kids thats how i got into burbans LOL,,,,

 

[Jims86]

Chaz, do you have an AIR pump on your Burb? Smog guys may be a little funny with an auto burb with a manual trans.

 

[adriner]

Ive got the same problem,,,89 burb 350 th400 on 35's runnin bout 3000-3100 rmp at 65mph,,,,I've been strongly considering a 4L80E swap out of a 91,,,,,but I'd absolutely love to have a manual trans,,,,I thought a manual trans swap would be mor difficult than an automatic to automatic,,,,can you tell me would a NV3500 bolt right up to my NP241 transfer case without driveshaft mods,,,,,???? If thats the case im gonna start lookin for the manual I really dont want to screw around wit all the electronic garbage,,,what bout my speedo,,,,I shold be able to run the speedo cable from the manual trans rigth to my speedo too right,,,,??? Thats bitchn,,,im gonna start lookin into that manual swap,,,,

Im not familliar with the np241 but It should bolt up if your 241 is a round pattern and a 32 spline output. NV3500s are cheap (my whole conversion cost me 150 bucks) they're a great road trans cuz the ratios are close. Mines holding up well so far and i beat the pis out of it, I do burnout's at 6-7grand all the time and she takes it and my 350 is rated 265hp, 320tq.. Just don't try to tow with it, the 4.-- first gear ratio sucks for pulling out.

 

[HotRodPC]

Im not familliar with the np241 but It should bolt up if your 241 is a round pattern and a 32 spline output. NV3500s are cheap (my whole conversion cost me 150 bucks) they're a great road trans cuz the ratios are close. Mines holding up well so far and i beat the pis out of it, I do burnout's at 6-7grand all the time and she takes it and my 350 is rated 265hp, 320tq.. Just don't try to tow with it, the 4.-- first gear ratio sucks for pulling out.

You must have a tall gear ratio too, I'd tow with a NV3500. Espeically the wide ratio version and a 4.02 first gerat which is full size Chevy trucks. S-10's get close ratio with a 3.49 first gear ratio. If a 700r4 at a 3.06 first gear, and Th350 and Th400 with 2.48 and 2.52 first gear ratio's can pull, a 4.02 1st gear ratio damn sure can. As said, NV3500 isn't as stout as the NV4500, but they are no slouch either. And if an NP241 will bolt up, then so should and NP208. It's a matter of getting a NV3500 out of a GMT400, but not the Tcase since it's driver side drop, them bolt on a passenger side drop NP208 or NP241C from a square and rock on with it. JUst be sure you're getting an NV3500 and Not a Get Rag or the Muncie version. To be on the safe side, I'd get one out of a 94 or later full size GM truck. That SHOULD ensure you're getting a true NV3500 and not an HM290 or 5LM60. They are all very similar and hard to tell apart, but the NV3500 has many changes and updates that makes it a better less problematic unit. So to be sure, just get it out of a 94 or later to avoid any transition years etc. Some will say 91 and later, some will say 93 and later, I say 94 and later to be sure.

 

[adriner]

Could be the fact that my trailer is a 26' deck over and It weighs quite a bit too haha

 

[HotRodPC]

Could be the fact that my trailer is a 26' deck over and It weighs quite a bit too haha

NV3500 is rated at 11,000lbs GCVWR (Gross COMBINATION Vehicle Weight Rating) That's pretty impressive really for a half ton transmission, and this for the Wide Ratio model, not the S-10 model. NV4500 is rated at 14,500lbs.

 

[Jims86]

NV3500 is rated at 11,000lbs GCVWR (Gross COMBINATION Vehicle Weight Rating) That's pretty impressive really for a half ton transmission, and this for the Close Ratio model, not the S-10 model. NV4500 is rated at 14,500lbs.

11,000 is the GCVWR on my Burb...I dont think I would ever exceed that. Hmmmm, this nv3500 very tempting.

 

[HotRodPC]

It's not bad. GM even used the NV3500 in light duty 6 lug 3/4 ton 2wd trucks.