Relatively speaking, there's not going to be a huge difference in cost between rebuiding the 4 or 5 speed. the only way there's going to be a difference is if you only change the bearings that are completely past it, but left in a few that were showing some wear but would still last a good few years. Any box I've personally rebuilt, of any type, i've tended to go the other way - unles the bearing (or whatever item) is in absolutely tip top condition, I'd replace it, and I ended up getting longer life out of them vs just doing the 'bare minimum'

SO on that basis the rebuild costs won't be astronomically different - you then have to look at what is a better gearbox all things considered. And on that basis, even if the strength difference is negligible, that extra gear is a MASSIVE advantage. You can run 4.11 gears and in 5th it'd be like having approx 3.3:1 diff with a 4sp. Huge drop in freeway rpms. Alternately if you find em, you could run 4.375 diff gears and it'd be the equivalent of around 3.6:1 gears in 5th. Those 4.3s would be good with a 'bigger' cam spec. I suspect that 4.88s would be a litte lower than ideal for a mild cam (more suited to competition stuff) - but just for the hell of it - 4.88s in 5th gear would be similar to approx 4.00:1 gears. so they'd see very very very slightly lower freeway rpm than with a 4sp and 4.11 gears (which you almost certainly have now)

So basically you can tailor diff ratios to suit the fact you have an overdrive 5th gear and get the best of both worlds, improved acceleration with the lower geared (higher numerical ratio) diff but a bit lower freeway rpms, or alternately simmilar acceleration (keeping your current 4.11:1 diff gears) and a much low freeway rpm, or alternatively a BIG improvement in accelration, but little change in freeway rpms.

So that's the first 'big advantage' of the 5speed and why it would be of benefit to rebuild it rather than a 4 speed.

The other reason won't affect you straight away, but down the track - it costs similar amounts to reco either the 4 or 5 speed, BUT if you ever wanted to sell the box, you'll get a decent price for the 5 speed (still won't likely recover all costs of course) but you'd likely have real trouble selling a reco 4 speed for much money at all.

It's not the HP, it's the torque. Box will do just fine for mild engine

I thought the Dato box was strong enought to handle some extra HP...
Is the 60A a stronger box???

If these boxes don't handle the extra grunt..what do people use as replacment boxes??
I can't imagine this engine making more than 85HP ?? correct me if i'm wrong...
Balancing should allow it to spin faster, cam should give it a bit more low end grunt but Overall I think it's a fairly mild unit...

Does anyone have a similar build that has been on a dyno and got figures???

You could first finish the engine run it in the traditional
way with the 56a or use the 60 series for quick run in.
5 speed of 60 and up would be the go.

Unless the 56a is noisy don't touch it. You will most likely kill it within minutes anyway.

Any reputable gearbox place will do the job and all bearings and synchros are available still. But be warned, these gearboxes are not designed for burnouts or chirpies.

Anyone know someone in Toowoomba or Brisbane that could do a rebuild for the 60A 5 speed..

Is this a trick question.. Go the 5spd

Hi All,
I have just pulled an A14 out of my ute to reco...
Going back in:-
H89 Head - ports tidied up, larger valves, decked, double valve springs
Mild Cam
10:1 pistons
Fully balanced
Genie 4:1 Headers
32/36 weber

Gearbox - I have both an 56A 4speed and a 60A 5speed
56A out of the ute and running OK - I want to rebuild just to know what is in there - at a minimum needs rear seal.
60A - unknown conditon - seems to turn well in all gears but not sure - would want to rebuild to be sure.

Which one do I do ? can't afford both..
Where can I buy parts for these?
Does anyone do kits for them?
I'm in Toowoomba QLD , close to Brisbane so can go there also..

Any suggestions??

The more I read the more I think I should sell to 5 speed and rebuild the 4 speed..

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