Boring the block to 79mm is a common thing for racing, as this makes the engine 1608cc's, which is allowable with CAMS' +3% rule. For the street, It depends on how you want to use the car. If it's a daily driver with a little cam, in my opinion the difference is not worth the cost. If it's an all out street racing engine, every little bit counts. It also takes away a lot of engine life, if you rebuild every 5 years or so with a 1mm overbore each time, that's 2 engine lives you've bypassed. You can get good quality 77mm pistons for about $100 Australian. I don't know what a good quality set of 79mm pistons would cost, but probably a lot more than $100. So, what do you want to use the motor for? If for a daily driver, they're not worth it, again that's just my opinion. If for racing, street or track, go for all you can get.

With your combination, you definitely need the longest housing. You can remove the engine plate & use either the engine plate, or if you can find a B310 (210) auto half plate, this has the right size holes for the 60A. Leaving the plate off moves the transmission forward enough to use the standard length housing.
Using the thicker A14/15 flywheel will move the pressure plate back enough to use the standard length. I have done the a12 flywheel with plate & 5 speed, & did need the long one. I got so used to it that when I did an A15 flywheel with no plate, the clutch completely locked up because of the long housing. It took me 3 removals of the trans before I was told what was wrong by a friend.

Have recently found that R30 Skyline engine brackets are shorter than 200b/Stanza/Bluebird, by about 25mm/ 1 inch. I haven't tried them on a crossmember yet, but this should give me enough clearance on the bonnet with my Sunny. Pity it's from such an old/rare car. I hope the sump doesn't hit the crossmember, in fact. They look easier to duplicate in plate steel, as well. I've been told the 120Y has a taller nose than the Sunny, but it's always nice to get the engine down as low as possible.

With my Sunny wagon, it also sits up at the front, using gas inserts. I think I've put Stanza stock springs in, which aren't compressing enough with the lighter engine. Plus the barstools are worn out after less than 12 months use. I'm going to replace the front end soon, so my solution for more negative camber is to use Stanza ball joints instead of Sunny. They have a greater offset outwards. I'll just have to lengthen the tie rods by screwing them out. I've used 200B steering arms in the past, with 180B outer tie rod ends to match the taper, but you need a spacer under the nut to get it to tighten properly. I've also got some shorter front springs that I'll fit, & another pair of strut inserts. I'm only using stock strut tops. I'm also going to have to find some heavier rate rear springs, as it goes into 'wormy dog' mod as soon as you put half a decent load in it. My old Sunny panel van with leaf springs was much better for carrying a load.

Years ago, a friend used an auto floor pan from a 120Y in a 1200 ute so he could fit an auto for the owner, who only had 1 arm. he used a r31 pintara box with an A series bell housing, & somehow wired it up to lock up the torque convertor, or however else they get 4th gear. Both the friend & the ute are long gone, but they both lived around Ingleburn in Sydney's south west in the 1990's. The friends name was Ron Johnson, from Ingleburn Steering, the customer was simply known as Gadget. I have seen a column shift auto in a Datsun 1000, so I think you've got a bit of h(a)unting in wrecking yards ahead of you if you want to find one.

On a pad by the dizzy, a little engine number, said what it is. the first 3 digits will say either A12, A13, A14 or A15. It could also be an A12A. Is definitely a late style A series engine.

A really good rule I always seem to forget is - Use what you've got. So, use the ute, instead of wasting time looking for another car. I reckon with a sensible power to weight ratio, good tyres & suspension, plus appropriate brakes, it should be just as nimble as a sedan or coupe. Too much power in anything makes for a real 'pants stainer'. So go for a racey A15, a good/ racey L series, or a lightly boosted turbo motor, depending on your leanings. I assume the real reason people have traditionally used sedans or coupes is that utes & wagons were banned above a certain level of racing, but there has always been the odd example.

Try & find a crossmember for a Sunny(B310) auto, which is pretty much identical to the 5 speed cross member. I use the Auto crossmember to put the larger 63A & stumpy 5 speeds behind L series motors. If you can get the 60 series 4 speed crossmember, it can be used with spacers & longer bolts between the crossmember & the floor. I found some very interesting spacers in R31 Skylines & Pintaras , they are C shaped, & are used to space down the gearbox. This is exactly what you want. With these you can start the bolt in before slipping the spacer washers in. Please fill in the location part of your profile so we can be a bit more specific with advise.

I'd make sure the engine was as good as possible, by getting the head serviced, the valve seats checked, new single valve springs ($20 for a set of 1600 VW springs), plus the best carby you can find. The new repro carby's aren't much good, but there are plenty of cheap 32/36 DGV's on Ebay. 1200's & 120Y's aren't that slow with a good stock engine, it's just they're all worn out. As for the bottom end, if it's got even compression, I'd leave it be. It's all pretty tonka down there, but a new water pump, oil pump & a new electronic distributor would help it stay healthy. A new rocker cover gasket so it doesn't cover everything with oil would be good, too. The 'bomb' car bashes always seem to have things breaking down, but that's probably how they edit the show. Always need a bit of drama, & comedy, too. A 120Y is light enough to fly over most surfaces, also. Use a Japanese rear end, a H145 because the Borg Warner alternative has a reputation of being weak. Get the 13 inch wheels with larger tyres, make sure the brakes work (can't go without stopping), then get ready for Hero status as the guy in the 120Y.

I assume JDM, due to the mirrors. They should have used the log wheel base chassis, in my opinion. would be fun to rock up to a Datsun show with one worked over.