75 replies to this topic

[yel327]

Muncie is good, heaps stronger than a Saginaw. M22 Rockcrusher Muncie is the big gun box. M21 is just a normal road box. There are a few different types too with big input and ouput shafts. The Muncie in a HQ GTS350 and XW8 Kingswood is a fine spline input and big output shaft box but it is an M20 (wider ratio) originally destined for a still born Pontiac GTO of some description. In any case any Muncie will handle a 350ci engine no sweat. Saginaws are marginal even in 300hp or thereabouts HT-HG GTS350.

[76lxhatch]

Score! The M20 Muncie is still relatively close ratio for a 'wide ratio' box, it has similar ratios to the M21 Aussie 4 speed, the M21 Muncie is even closer. The number you want is the one stamped sideways on the rear edge of the main case, starts with a P: http://www.chevelles...m/qd/muncie.htm

[yel327]

Be careful with it, they smash easily. Marginally stronger than an aussie 4spd but not a huge amount. A brand new M20 or M21 Muncie is about $1600 US and it'll basically fit where the Saginaw does. Shifter is slightly different, speedo cable is on a different side. rear mount is close.

[myss427]

Easy way to tell Muncie from Saginaw is the muncies reverse shift lever is in the extension housing. Saginaws is on the side with the other shift linkages, also have only ever seen alloy case muncies but have herd of very early cast ones. All saginaws are cast steel.

[yel327]

Doesn't include postage or GST. Look here:

http://fourgeartrans.com/id5.html

Either will do the same job. M20 iis 2.52:1 1st, M21 is 2.20:1.

Just use a HQ 350 manual speedo cable. Should operate the Torana speedo OK. Muncie is RH exit speedo cable. You could simply reroute the Saginaw one but it'll be about 1/2 metre too long.

Tailshaft will be the same if you get a 27 spline output shaft. 32 spline uses a TH400 yoke and would need an adapter uni (1" on tailshaft axis, 1.125" on yoke). If you get a 10 spline input shaft t'll use the same clutch as the Saginaw. 26 spline will need a new clutch plate. Bellhousing will be the same.
I'm pretty sure the rear mount is in the same spot.

Shifter should be in the identical spot but you have to shorten the reverse shift rod as the Muncie reverse is in the extension housing like an aussie 4spd. I have an M21 Muncie here that was in a VK Commodore and the Hurst shifter has been modded to bring it over to the factory Aussie 4spd hole so it can be done. You'll probably need a small hump on the side of the tunnel like a HQ GTS350 manual or an A9X (for the T10 which is an earlier muncie type design and has a very simlar shifter location).

[76lxhatch]

Those brand new M22s with the wide(ish) ratios, super case etc look awesome, and for US$1775 you can't really go wrong!

As for the shifter Speco still list a centre shift, or you can just modify the usual Hurst offering - this is what I'm about to put in:

[76lxhatch]

Bugger, I assumed they were still available because their web site lists them:
http://www.speco.com.au/accshifts.html
They do have different part numbers for the different boxes but external linkage shifters are pretty simple to adapt to most boxes, its generally only a different linkage and/or a few tweaks.

I didn't investigate the centreshift any further because the box came with a perfectly good Hurst Indy and I reckon its a better design anyway - I just started cutting and welding to tuck it out the way...!

[76lxhatch]

Out of interest I installed the box today with the modified shifter and linkages as shown and it fits in the standard tunnel... just!

[yel327]

Not as good as a Muncie! Different bellhosuing too. Different tailshaft, clutch, rear mount etc.

[greens nice]

they are called a poxloader for a reason.

[yel327]

A Top Loader isn't as good as a Muncie? The shifting is smoother too isn't it? I thought he'd have to get all of that minus the tailshaft anyway?

Toploaders are good strong boxes, but Muncies were fitted to GM vehicles for use behind big blocks and factory race cars like Z28's. As soon as they stopped building high performance big blocks and hi-po Z28's they stopped using them and replaced them with the Borg Warner T10 which was an older design and less heavy duty box. If the car has a Saginaw in it now, a Muncie is basically a bolt in replacement. A Toploader is a full conversion from scratch, plus a brand new Muncie would be close in cost to a rebuilt old Toploader.

[76lxhatch]

Yeah all the GM boxes have good interchangeability so not much point in wasting money on something different when its already set up for this and there are good options available. GM T5 (not from a Commodore unless early VN V8 I think) is also interchangeable, although its no Muncie!

As I understand it the T10 was the old box before the Muncie, Super T10 was what superseded it - seems to depend on who you ask as to whether these are on par with a Muncie or not, but I think if you were to look at buying a new box both have their improvements and would be much the same. The biggest advantage the Super T10 offers these days is the bigger range of ratios available. Some of the earlier Muncies had a smaller layshaft and aren't up to big power either.

[myss427]

The Super T10's are newer, most Muncies have been arround for years and would have been thrashed most of the time by now. So unless it has been fully rebuilt with new bits I would go T10, similar stength except rock crusher, but finding a mint one of those for a reasonable price, good luck! And you can buy brand new Super T10's for $1550 from Summit and Jegs.

[76lxhatch]

Price was up around US$1650 for the Richmond Super T10 when I checked recently, and as above you can get a new and improved M22 for US$1775 (a bit less for M20 or M21) so they are all much the same in terms of price and probably quality so it really comes down to ratio preference as the shifters are all basically the same too. The noise of an M22 would be cool though...

I took a gamble on a second hand box that had supposedly been recond and it actually looks and feels pretty good inside so I'm happy, but its nice knowing there is an option to upgrade later.

I find it interesting that the guys talking about limitations of the Muncies either have problems with cases stretching or breaking shifter linkages/levers/forks. Obviously the gear sets aren't really a problem and they really don't have any mechanical sympathy when shifting gears!

[yel327]

The Super T10's are newer, most Muncies have been arround for years and would have been thrashed most of the time by now. So unless it has been fully rebuilt with new bits I would go T10, similar stength except rock crusher, but finding a mint one of those for a reasonable price, good luck! And you can buy brand new Super T10's for $1550 from Summit and Jegs.

No-one would buy an old Muncie nowadays when you can buy a band new box in large ouput shaft, fine spline, M22, with steel sandwich plate for less than $2000!
Remember GM stopped using Muncies and went back to the T10 once the high horsepower factory cars were done and dusted. If you have big block torque a Muncie M22 is the go. Small block, Muncie M20 or M21 or Borg Warner T10. Old GM T10's and Muncies, leave them for the resto boys!