48 replies to this topic

[dattoman]

Hypothetical question

 

Imagine if you will a stout V8 in an LH-X 

We'll call it a 383 Chev small block for argument's sake - 480 wheel HP

3.55 rear axle ratio

Available tyres around the 265 size likely in 17" diam

 

Box options at reasonable prices and somewhat sensible

Here's the readily available options... most avail brand new still... but the 5 and 6 speeds are very pricey

Even to buy a T56 or TR6060 second hand and refresh are getting up there in $$

 

Super T10 

M20 Muncie

 

TKO500 + 600

Doug Nash 4+1

T5 ? .. .are these even strong enough ?

 

 

T56

T56 Magnum (long convo with Mal Wood yesterday... no change from 12k+)

TR6060

 

Any other suggestions ?

Things you have used ?

Easy conversion kit avail helps

 

No Autos... must be manual

 

[N/A-PWR]

Super T 10

[yel327]

Muncie, better box for a big torque engine. Pretty sure you can get M20 gearing with M22 rock crusher gear pitch and the boxes aren’t too badly priced brand new from the US. Fitment is basically the same as T10. You can buy them to use TH350/‘glide yoke or TH400 yoke too.
What clutch arrangement? I’d be using a 308TH to GM manual bellhousing with cable clutch and bugger around with a UC clutch pedal. Will it be an internal or external balance stroker? Reason I ask is I’m not sure if you can run an 11” external balance flywheel in a Dellow or CRS bellhousing.
HQ Muncie speedo cable should fit. Gearbox crossmembers are available cheap and Engineered on EBay. Pretty sure if you use HQ 350 engine mount adapters the T10 or Muncie sits in the same place as they do behind a Holden V8 so just copy an A9X shifter setup. If you use HK-HG mounts the engine moves back about 3/4” so the box does too. It also sits lower a bit.

When you say 3.55 gears, do you mean a 10-bolt? A 377+ci SBC with 4spd will eat it for lunch! Especially if an LSD and 265 tyres.

If you aren’t in a hurry I can get you a photo of a setup exactly what you’d want, I just can’t get to it easily. It is an M21 Muncie that was in a Commodore behind a 308TH pattern 350 stroker. Shifter is setup to come out in a VK Aussie 4spd console. Photo will show you what it all looks like when setup to go so might help you envisage the setup. I kept this to put behind a 427 in my GTS327, plan to use it until the big block eats it and then buy a new M22.

Have a read here about new Muncie. $1895 will become something like $3000+GST though.
https://www.5speeds.com/newm22.html

[dattoman]

If you can get some pics that would be nice

 

It's actually a BW with 28 spline axles going in the rear

I was thinking of going hydraulic clutch with internal throwout in the box

 

Mal didn't mention Supra boxes at all ... though neither did I

Actually I did...I mentioned the W58 I have in passing but we didn't discuss it... .certainly not up to the task

[yel327]

Will try and get a picture or two. It is at the back of a pallet under pallet racking with a pile of HK 10 bolt and 9”
diffs in front of it blocked by a HK coupe body.

A stroked 350 manual might lunch that too. My mate’s 350 with 4spd used to tear the guts out of 9” centres with 265 tyres. Had to go to a full spool and 31 spline axles to stop it. Then had to refit a Muncie as it started eating Top Loaders.

Edited by yel327, 19 June 2020 - 10:47 PM.

[76lxhatch]

Unfortunately good manual gearbox options are not as simple as automatic and much more expensive, but its worth it :-)

 

I had a Muncie that I made fit in the standard tunnel using modified Hurst shifter and custom linkages (necessary if you want a console), I reckon its not a bad option to go with one of those new heavy-duty boxes if you don't mind a four speed. They can be made to shift very nicely and a lot of fun to drive.

http://www.gmh-toran...e-8#entry725344

 

I don't see how the Supra box would fit properly without at least a little cutting, even the W58 needed a bit of extra around the shifter and forward a little if you want decent driveline angles. To me trying to fit anything bigger without cutting is just shooting yourself in the foot as you're trading one problem for another, I'd rather have it done right (watch out for bolt-in 'kits' that don't require cutting). You also need to allow for bigger driveshaft yoke even with the 32 spline Muncie, the five and six speeds are worse as they are longer and move it further rearward.

 

Some people get away with T5s but I wouldn't spend money on one as its lifespan is more likely to be short, little better than the W58.

 

Hydraulic clutch release works great with the throwout bearing type. The clutch itself depends on how you drive the car and how often. I had a few different heavy duty single plate setups and the only one that lasted long was ceramic button on the pressure plate side but it was worn out in under 24 months which apparently is normal. Now have a twin plate full organic setup which seems to work well and should last longer but price is not "reasonable".

Ceramic clutch damage, hydraulic throwout, also scroll down to see tunnel cutting for TKO:

http://www.gmh-toran...-11#entry900805

Twin plate clutch:

http://www.gmh-toran...15#entry1027214

 

I'm reasonably happy with the TKO600 now things are pretty sorted but it didn't fit easily, in hindsight I'd probably just take the simpler route and go T56/6060.

 

Also have the 28 spline Borg Warner with factory R31 axles and Tru-trac. Only behind a mild 355 but they survive this sort of thing:

Well, sort-of. Both axles are showing a bit of twist at the spline end so no more of that for now. Kind of invested in the 28 spline now since the centre was so pricey, in hindsight I'd go straight to 31 spline but I'm thinking some decent custom axles in 28 should be enough to solve the problem.

[yel327]

I just remembered the UC I had with 302 and Muncie. I didn’t actually buy the car but the driveline. What they had done was turn the gearbox 1/2 and 3/4 selectors 180deg so the shift rods were underneath and cleared the floor. It meant the shift pattern was still a H but with 2 and 4 at the top. I drove the car before it was wrecked and was OK once you got used to it.. Good anti theft feature too as anyone stealing it would try to takeoff in 2nd and then struggle to drive it initially. I only just remembered it when I was looking a picture of one of those modified Muncies where they turn 3rd into an overdrive and turn the 3/4 selector 180deg.

[yel327]

There has been a few Muncies and T10 on Gumtree lately, but sometimes I wonder if they are worth it. Although the freight cost of parts would be cheaper you’d probably end up spending the same or more. Also the shifters may be worn out. Examples:

https://www.gumtree....rbox/1250298456

https://www.gumtree....sing/1248639805

[yel327]

Also remembered Datto, when putting the SBC into LH-UC that HQ engine mount adapters as well as moving the engine forward 3/4” compared to HK-HG they also tilt the engine just like they do in HK-HG. I’m squaring the engine up in my HK by using two short spacers and it also moves the gearbox closer to centre, meaning the gearbox crossmember I bought was made with the gearbox mount centred rather than off to one side. So watch for that when setting up. The problem with HQ adapters is you can’t use two the same as the mount is offset, although if you used two short ones you’d just need to drill 2 holes in one side for the mount as a mirror of the other side. You could try using HK-HG mounts and two short or two long spacers and see how it fits, pushes the engine back 3/4” though but gives you more sump clearance. Might cause yoke area to floor issues though.

[rexy]

The beauty of the R154 is that not only are they super strong but they have beautiful shift quality, unlike many of the others mentioned. Clutches are cheap. I have run HD Holden pressure plates with standard organic lining Toyota driven plates. Behaviour is excellent and they last well.

i have one setup with cable in the hatch and one setup with hydraulic in the LJ. Both are fine but the commodore style cable in the hatch does seem to need adjustment often.

[yel327]

Will it handle the torque of a 377 odd cube SBC? GM specced transmissions based upon torque not hp. Big cube V8’s were why the Muncie was built and they stopped using them once engines dropped in torque and hp.

[neglectedtorana]

I have a T56 and it is great but I would prefer the overdrive ratios were closer which can be had with a Magnum box however these guys have some Commodore T56 boxes at reasonable prices. Still require a shifter relocation or different extension housing

 

https://www.holmart....mission-clutch/

[rodomo]

202 and Aussie

[gtrboyy]

Don't they all require some sort of tunnel mods or cutting?

 

ford 6cyl t5 conversions drive nice + cheap & reasonably common although with 500hp you either want to treat nice or keep a spare for when 3rd gear exits

 

 

t56 cheapest of the six speeds to buy,probably want to go shorter 3.9-4.11 gearing

 

 

Do like idea of ol skool t10/muncie 4 speed for a street car though.

[Oversteer]

How did you get to 12K for the magnum ? when i bought mine the box itself was $3.5K, add bellhousing clutch and tailshaft ~$2.5K

 

Would use the R154 all day long if I was you, no comparison in shift quality to the others, they are All non syncro truck boxes compared to a beautiful precision instrument, and they'll take well over 1000nm

Edited by Oversteer, 21 June 2020 - 05:07 AM.

[dattoman]

How did you get to 12K for the magnum ? when i bought mine the box itself was $3.5K, add bellhousing clutch and tailshaft ~$2.5K

 

Would use the R154 all day long if I was you, no comparison in shift quality to the others, they are All non syncro truck boxes compared to a beautiful precision instrument, and they'll take well over 1000nm

 

Mal Wood prices

He was talking 6k for the box and about 6k worth of supporting parts... bellhousing ,clutch underdash master etc

 

I have access to Toyota parts thru work

So going to look into the R154

[Toranamat69]

I would be using a twin or triple plate clutch for this performance level.

Heavy single plate is not nice to live with and was very tough on my clutch pivot point and twisted the pedal assy.

[Toranamat69]

I noticed these new boxes on Ebay recently.

https://www.ebay.com...xjSoBFH9a9qXwtQ

https://www.ebay.com...xT8_KHDITHN0_cw

Shifter look wrong for Torana though.

There was a third type listed with a better looking shifter but the first gear was crap from memory.

[Toranamat69]

https://m.facebook.c...dtekAutoRacing/

These guys do a HD close ratio gear set which would be perfect. I haven't coughed the cash for that yet.

[Toranamat69]

https://www.ebay.com...T8AAOSwNKVXMakI

[Shiney005]

I have access to Toyota parts thru work

So going to look into the R154

With the latest Landcruiser 5 speed manual @ $3,500 with all accessories, it might be cheaper than you think Neil.

[unclefestal34s]

Gearboxes choices are quite easy for me to make from my own driving and drag racing experience,..muncie fine 26 spline 2.52 first gear ratio 32 rear same as turbo 400,...super T10 second design 2.43 or 2.64 first again 32 rear ,..Doug nash 4+1 street box stronger than tremec...and bang for buck Top loader gearbox you can't go wrong with,...Muncie rockcrusher with its 2.20 first gear isn't very user friendly behind a small block when driven aggressively as they were design for a big block with more torque..i'm currently running a rockcrusher box in my 69 Camaro 350 SS with a 12 bolt diff and 4.10 gears,..great to drive and cruise,.but when leaving the line you have drop it big to respond its making 480hp @ flywheel..all these gearboxes require some sort of tunnel work for a comfortable fit,.you can get away with minor massaging of the tunnel if your anal and have a hoist... my personal opinion, i've driven cars with 6 speed gearboxes in them and don't like one bit including the excessive tunnel modifications etc..Just my thoughts and opinion..

[yel327]

You can buy M22 wide ratio gears sets now too not just the M21 ratios. Look at the link I put further up this page. These are what they list (original M22 first):

M22 2.20 1.64 1.28 1.00
M22W - DS 2.56 1.88 1.37 1.00
M22W - DS STD 2.56 1.75 1.37 1.00
M22W 2.56 1.75 1.37 1.00
M22X 2.20 1.51 1.17 1.00
M22Z 2.98 2.04 1.47 1.00

The DS is a drag special unit with a special thrust button case. They also use needle rollers on the selector shafts to improve the shift feel.

Remember though that a 3.75” stroke 4” bore 377ci SBC with modern heads and roller cam is going to be getting similar torque to the smaller BBC’s the M22 was designed for, like 396 and 402. I have heard what UncleFestas says though from people having that box behind 302ci engines in Z28 Camaros, and from others that have had the M21 ratio boxes and replaced them with an M20 to make them more suitable for daily use.

When you read about the improvements on modern ST10 they do very similar strength and improvements mods to what these modern Muncies have. Either would probably do the job with no compromise either way especially in a light car like an LH. I’d avoid old stuff, but if you find one of either use it as you plan to sell the car.

Edited by yel327, 21 June 2020 - 10:02 PM.