Hello and welcome Matt.
NoiseDepends what you mean by noisy. There's good noise and bad noise.
I think it is possible that what you are describing is an intended design feature.
Firstly, the transmission works from low to high gear mechanically by engine speed. As the primary unit speeds up, the pulley halves are pushed together at the front which in turn forces the rear halves apart. Secondly, on top of this basic mechanical action is added vacuum action. If engine vacuum is introduced to the outer primary chambers it works with mechanical action to increasing the gearing for a "overdrive" effect (engine revs go down) and if engine vacuum is introduced to the inner primary chambers it works against the mechanical action to give a "kickdown" effect (engine revs go up).
What happens when slowing down is that when the brake light switch is activated, vacuum is introduced to the inner primary chambers and drops the gearing down and the engine revs rise, the idea to give some engine braking coming to a stop.
So unless it is a bad noise were talking it about, we'll assume it is this (normal) behaviour.
Rear seatbeltsFrom a legal point of view (
www.gov.uk/seat-belts-law/if-your-vehicle-doesnt-have-seat-belts), you don't need to fit seat belts in the rear providing they are over 3 years old. If you want to fit seatbelts, then you might be able to fit something. I'm not sure if the D55 already has anchorages in place, but if not the location and reinforcement could be copied from the Volvo 66 which did have them. I would suggest you contact Quickfit Safety Belt Service of Stanmore, Middx for further advice (
www.quickfitsbs.com)
AlternatorYou can fit an alternator if you so wish. From memory the DAF 66 has an alternator with a separate voltage regulator.
Electronic IgnitionAs far as electronic ignition goes there is a wide choice. In its most basic form you have an electronic switch which is activated by the contact breaker, but because the electronic switch does all the work, the contact breaker set lasts considerably longer and you can say goodbye to dodge condensers.
Next up the price/tech scale is a magnetic switch, such as a Aldon/Petronix Ignitor. The contact break and condenser are ditched in favour of a magnetic trigger ring and a pick-up. Fits neatly inside the distributor, but you're still at the mercy of sloppy shafts and mechanical advance mechanism.
Following that, there is the well proven Lumenition Optronic, which uses a optical switch instead of a magnetic one.
Expensive but gets rid of condenser, contact breaker, mechanical advance and therefore eliminates the effects of a sloppy drive shaft is the 123ignition.
Fully mapped electronic ignition - Megajolt and the like.
Pays yer money and makes yer choice.
Unleaded petrolOn the subject of unleaded. Although these aluminium heads have hardened valve seat inserts, they are not well 'ard and you will see valve seat recession if you spend 24/7/365 revving the tits off it up and down the motorway. However if the vehicle is driven moderately, the seats will last quite well as they are.
If you choose to use an additive. Use an FBHVC recommended one and stick to it. Castrol Valvemaster or Millers VSP spring to mind.
If you want harder seats fitted, most competent engine shops should be able to oblige. If you want to do a straight swap of a weekend I don't think it would be too difficult to source a second-hand head to do the work on first to enable a swap-over job to occur.
Personally, I run them as they are until a problem occurs then deal with it.
Hopes this helps and if anyone else would like to chip in...
