NV4500 or 700R4

[57chevywagonman]

I have a 1965 GMC 3/4 ton camper special. The original V6 is long gone. I am using a 4 bolt main 350 from an 84 Corvette with a 4bbl carb and a comp cams camshaft upgrade. I have a 700R4 from the same corvette. Should I use this or hunt up a NV4500? I plan to use the truck as a shop truck and it will occasionally pull a trailer with a car on it.

Thanks!

All the best!

Mike

[ilvracn]

700R4 is a light duty trans, if you go this route, do not tow in overdrive. nv4500 is made to pull. i would put new synchros in before install. synchro gears have fiber facing not brass, tend to wear, grinds when shifting, especialy 2nd and 3rd gears

[POWERSTROKE]

I'm not a big fan of the NP4500, the Dodge diesel pickups had problems rattling off the over-drive driven gear I think it was, had a splined shaft they threaded and tightened the gear on the shaft with a thin jam nut. In a situation with a high rpm smooth running V-8 shouldn't be a problem. Don't lug the engine in over-drive.
Only NV4500 I ever drove was in a Cummins powered Ram 3500 duallie, synchros were totally out of 2 gears, very weak in a third gear, so I agree, unless you KNOW synchro's are good, replace them before installing trans.

I don't think there are different gear sets for the NV4500, like the wide ratio and close ratio gear sets for the ZF 5S-47 in my old '96 F-250, the diesel engine, 7.3L PSD got a close ratio, 460 gas got a wide ratio. For your Corvette repower I would think a close ratio would work best, less rpm drop with each shift, top gear cruising would be at 3000-3500 rpm.

[57chevywagonman]

OK! I have located an NV 4500 with the Chevrolet bell housing for a very reasonable price. I am aware that I may have to replace the synchronizers but that does not really scare me.

Can anyone help me out with what flywheel I need to mount on my '84 350 and what clutch I need for a heavy duty application? are there issues with pressure plates and flywheel compatibility on GM vehicles?

Thanks again for all the help so far.

Mike

[ilvracn]

The crankshaft you have has a 2 piece rear main seal. This means you need to order a flywheel for the older 350 engine, 86 and older. I would order a clutch and flywheel for an older c30 truck with a 350 engine, say around 1978. There are 2 types. I would get a diaphram style clutch, but i don't recomend the button style clutch, unless you are really going to work truck. Button clutch has a harsh engagement, tend to chatter. I would get a pilot bushing, most clutch kits come with a bearing. The bearings fail fairly quickly, because the don't hold enough grease. Do not put grease on the bushing, it works much better to soak brass bushing in atf for a couple days, if you have the time.

Oriely's has parts available
clutch # k1909-02- $110.00
flywheel # nfw1007 - $75.00
pilot bushing # pb656 - $3.00


rick

[57chevywagonman]

Thanks for the clutch advise! I am going to get the transmission on Thursday. Hope it all turns out OK.

All the best!

Mike