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RichardSIA Reader
12/26/19 2:24 p.m.

Bad starter ate the ring gear in my 81 C-30.

So the engine or trans has to come out for the repair.

I would like to increase mileage a bit which pretty much means overdrive.

But I do not want to give up my "Granny gear" low ratio first gear as I sometimes carry or tow heavy loads.

Can anyone suggest a strong and reliable used transmission that provides both at a decent price?

If I pull the engine I may do a cam and intake swap as well as installing the headers I already have.

Not sure about keeping the Q-Jet or putting a smaller Holley/Weber on it.

I know how to tune a Holley/Weber, but not the ^%$! Q-Jet.



A 401 CJ
A 401 CJ Dork
12/26/19 2:41 p.m.

I don’t know about the transmission but I would never give up a Q-jet for a Holley.  Especially in a truck.

pres589 (djronnebaum)
pres589 (djronnebaum) PowerDork
12/26/19 2:42 p.m.

MY6?  Chevy's flavor of the A-833OD.  Was in a number of their trucks from that era.  Wide ratios.

RichardSIA Reader
12/26/19 3:33 p.m.

Well, that had poor first gear but led me to the NV4500.

Which looks good in some ways but seems to be a bit of an issue to fit with it's hydraulic clutch.

Also uses funny trans fluid and is a bit weaker than my SM465.

Close enough I will talk to my transmission guy about it.

Daylan C
Daylan C PowerDork
12/26/19 3:38 p.m.

ZF S6-650? 6 speed from newer GM and Ford HD trucks. Not nearly as common or cheap as the NV4500.

81cpcamaro Dork
12/26/19 5:02 p.m.

I have a NV4500 in my 93 Silverado 6.5L, pretty good transmission IMHO. I have owned a couple trucks with the SM465 and the NV shifts a bit better than them. Hydraulics aren't too bad (external slave cylinder on mine), clutch action is a bit lighter than the older trucks with SM465. It may be possible to use it with a mechanical linkage, should be info on the web about that.

RichardSIA Reader
12/26/19 5:24 p.m.

May have found an NV4500 locally at $600.

Have to research how hard to fit.

No Time
No Time Dork
12/26/19 5:28 p.m.

I'm not sure which year GM made the change to Hydraulic clutches, but they did make the move to hydraulic clutch somewhere between '83 and '87 on the square bodies.

I do know in 87 the K2500 used a hydraulic clutch with the SM465 and  6.2L diesel. That might be a starting point for finding a suitable donor for a pedal assembly (also bell housing and clutch fork) if you need to move to a hydraulic clutch. 

ebonyandivory PowerDork
12/26/19 6:10 p.m.

Too bad the bolt on overdrive units are so much $$$

Recon1342 HalfDork
12/27/19 6:21 a.m.
RichardSIA said:

May have found an NV4500 locally at $600.

Have to research how hard to fit.

Good luck on the trans hunt. Popped in to say this-

Keep the Quadrajet!!! If you take your time and learn how to properly tune it, it will pay dividends. Q-jets are probably the best street carburetor out there. I rebuilt dozens of them when I worked on boats for a living, as they are the standard carb for Mercruiser stern-drives. I would take a Q-jet over a Holley or Edelbrock any day if the application was street driven and needed to be reliable. 


93gsxturbo SuperDork
12/27/19 8:11 a.m.

Good news is the Chevy bellhousing pattern is common with everything made in that era, so finding an NV4500 and making it work is just a matter of getting all the correct bits.  A hydraulic clutch wouldn't scare me at all, worst case you need a Tilton master and some bracket work.  Would also be an excellent chance to upgrade to a hydroboost.  

I think I would skip on the 6 speed versions, not a whole lot more gain for a lot of spend.  Plus they are HUUUUGGGEE.


Patrick MegaDork
12/27/19 8:47 a.m.

The hydro clutch pushes a normal clutch fork so it should be a matter of stabbing the nv4500 on the existing bellhousing with the mechanical linkage, no?  I've had plenty of sm465's and never enjoyed them.  Overdrive doesn't do much when you're carting around a c30, would you drive it enough beyond 4th gear to justify the cost for a small gain?  

RossD MegaDork
12/27/19 8:55 a.m.

Didnt Curtis just write up something about how awesome Quadrajets are?

Gearheadotaku GRM+ Memberand UltimaDork
12/27/19 10:06 a.m.

The SM465 is my favorite heavy duty manual. Yes, the lack of O/D is a pain. Gear Vendors overdrive is my first answer, but they are pricey.

 Curious the hear more about a NV4500 retrofit.

What rear gear do you have? What engine? If you're running around empty on 4.11's all the time, a 3.08 swap may be cheaper than a trans change. Granny low will still get you rolling with a taller rear gear.

Tk8398 Reader
12/27/19 7:49 p.m.

The only reason to get rid of the quadrajet would be if you were going to 5.3 or 6.0 swap it with EFI, otherwise definitely keep it.

81cpcamaro Dork
12/27/19 8:14 p.m.

In reply to Gearheadotaku :

If it is a dually, then it probably has the Dana 70 rear. There aren't any tall gears available for it. Pretty much the same for the 14-bolt GM rear. Both seem to be limited to 3.73 or lower. Dodge did have a 3.08 geared Dana for the early Cummings, but it is not real common.

The early NV4500s like my 1993 have the granny low like the SM465, later ones have a taller granny gear (not as steep).

Daylan C
Daylan C PowerDork
12/27/19 8:24 p.m.

In reply to 81cpcamaro :

My 1989 D350 had that 3.07 gear Dana 70. Carrier and case are slightly different so the ring and pinion don't interchange. I found out when I wanted to go to a a 3.54 LSD setup after destroying a diff.

RichardSIA Reader
2/8/20 2:46 a.m.

Supposed to get an early low gear NV4500 on Monday.

I do spend too much time driving around empty, hopefully the OD will help a bit.

Also found that the engine has massive ring leakage, which may explain the lack of power and horrible mileage, so a rebuild has begun.

Too much work to do twice, so doing the engine and trans at the same time.

Heck, even fixing the body and bumper.

Will be a fairly nice truck when done,  I will have to drive it for the rest of my life to get my money back.

81cpcamaro Dork
2/8/20 10:21 a.m.

It will help out. I have had both (in different trucks) with 3.73 gears and the NV OD is nice. I can cruise on the interstate at 75 mph without the engine screaming its guts out.

Vigo MegaDork
2/9/20 12:08 a.m.

Well, sounds like this is settled and the truck is going to be awesome. I probably would have done a gear swap if possible. My thinking is you're going to end up with .7 or .8 to 1 if you get an overdrive. Would your granny gear all of a sudden be useless if it was 20% taller? If the answer is no, gear swap. Maybe i'm goofy but I see the granny gear as being especially forgiving of a taller rear end ratio, more so than a lack of granny gear is forgiving of heavy loaded starts.  Anyway, post pics. smiley

RichardSIA Reader
2/9/20 12:18 a.m.

Got my new camera so pics are back on the agenda.

Once it's all sorted I will probably sell the old trans as surplus to my needs.

I had not planned on an engine rebuild or trans swap so this will take longer than I will be happy about.

In the end the truck will be strait again and running as well as possible without adding the complications of fuel-infection and computers.

RichardSIA Reader
2/14/20 10:28 p.m.

Two steps forward, and a step back.

Got a good deal  on an NV4500 with granny low.

The necessary adapter bell-housing was in stock at Summit Racing, except that what came in the box is not what I ordered. sad

So on Tuesday I will exchange it.

03Panther Reader
2/14/20 11:48 p.m.

I'm glad you got the trans. figured out. On the "Quadra-Bog" thoughts, its well worth the effort to get it dialed in right! The joke name and rep came from people that didn't get 'em right. A AFB/Edl/Weber is more forgiving right out the box. Holley, well, everyone know's why their name is huge. But the small primary / huge secondary are great at managing street mileage, reliability and power.

RichardSIA Reader
8/31/20 12:38 a.m.

After far too long I am to get my block from the machine shop late this week. 

Been painting/detailing what I could while waiting. So the new heads are now Chevy orange, along with the pan and TC cover. New aluminum water pump as the iron one had a crack in the casting, chrome Moroso valve covers because they were laying around and I despised the black "Mr. Goodwrench" set.

Bell housing is on the trans and will use the original mechanical clutch system.

Bummer is that it looks like I need to drop about $100 to sleeve the end of the input shaft.

This is the problem with roller pilot bearings, when they fail they are steel on steel and gouge the input shaft. I may just run an old fashioned bronze bushing as I have never seen one of those chew up an input shaft. 

Plan is to run-in the engine on my test stand, pics when that happens.

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) GRM+ Memberand UberDork
8/31/20 7:28 a.m.

In reply to RichardSIA :

I re-read this thread from when you first posted. I don't think I saw what engine? I assume a 454.

My neighbor has a 350 in his C30.

Curious about the build, aka project creep (don't feel bad, you're here among friends).

What heads?

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