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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.

Daylan C
Daylan C GRM+ Memberand 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.

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 GRM+ Memberand 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 GRM+ Memberand 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.

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

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.

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?

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
8/31/20 9:18 a.m.

I will also chime in.

I would never ever ever ever ever ever ever trade a Qjet for anything unless you wanted to go EFI.  The Quadrajet is hands down, bar none, the most accurately metering carburetor on the planet.  Ever.  Better than a predator, Carter, Holley, SU, Weber, any of them.  It is actually even better than the TBI that replaced it.  In fact, many TBI folks have swapped their TBI out for a Qjet and picked up power, torque, and MPG.

The man who was partly responsible for the Qjet is a fishing buddy of mine.  He is also partly responsible for the TBI but he's so embarrassed by that he doesn't tell anyone he had anything to do with it.  The Qjet was able to pass EPA standards with flying colors up through 1989, and could have been continued for several more years.  The push for the EFI was mostly because "everyone else is doing it."  

20 years ago, I would have considered myself a Qjet expert.  I have modified them extensively.  Sadly, that was 20 years ago and I haven't touched one in over a decade.  I can try to walk you through some simple stuff if you want to rebuild it.  They seem complex, but they really aren't.

As far as trans is concerned, the S6-650 is a sweet piece.  The granddaddy for the medium truck sector is the NV5600, but they tend to bring big bucks, and were primarily used in Dodge, so not an easy bolt-in swap.  If you want to go automatic, you're limited a bit.  The TH475 will take lots of abuse, but the ratios aren't something you'll be happy with.  4L80E will take the torque, but still not very good ratios, and tons of electronics to deal with.  I suppose some of the newer Allisons could be adapted, but again... electronics.

buzzboy Dork
8/31/20 2:26 p.m.

The national average miles driven is 13476. If you go from 9mpg to 10mpg, at today's national average gas price of $2.23 for regular, that would be a $334.50 savings annually. That's damn good.

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
10/5/20 11:04 p.m.

If it were a running engine i'd say you should play the lottery, since ring gaps move when running. Heck, i wonder if lining them all up makes for easier priming/cranking on initial startup before they gradually do whatever they wanna do anyway. smiley

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
10/19/20 2:49 p.m.

I throw the wristpins in the freezer too. Is that also against the rules? My first job was in an automotive machine shop when i was 15. The rod heater was an old gas stove!  Having said that, i understand pretty much any rod could be hurt by improper heating. They probably just said boiling water since it's basically impossible to heat something past 212* that way, which puts a hard limit on how much you're heating the thing. Heating it to 212 any other way would probably do the exact same thing. 

ShawnG UltimaDork
12/21/20 12:40 a.m.

NV4500, they're great. We're putting one in a '69 Suburban.

Keep the Q-jet. Stop thinking of it like a Holley, it's really an SU in a different package.

Cliff Ruggles literally wrote the book on tuning Q-jets, you can find everything you need on his website. Or give him a call and tell him what you're putting it on and he can set you up with the jets, needles and springs you need.


03Panther SuperDork
2/12/21 8:55 p.m.
ShawnG said:

NV4500, they're great. We're putting one in a '69 Suburban.

Keep the Q-jet. Stop thinking of it like a Holley, it's really an SU in a different package.

Cliff Ruggles literally wrote the book on tuning Q-jets, you can find everything you need on his website. Or give him a call and tell him what you're putting it on and he can set you up with the jets, needles and springs you need.


I don't know SU's well enough to compare, But the" Keep the Q-jet. Stop thinking of it like a Holley" part is as true as anything I've ever heard! Q-jets are one of the most "maligned due to not understanding" devices out there!

03Panther SuperDork
2/12/21 9:18 p.m.

Easy is not really the best way to describe a Q-jet... I don't know them well enough to tune one in right, and I can, on a Holly  or AFB; or most motorcycles (I'm a fan of the S&S E) But I know when they are right, they are my favorite street carb on a V8, at least.

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