OK firstly
don't dispare you failed on the most fasionable things to fail on
secondly
remeber your car is basically an American 66-68 A body in all but body and trim so all of it can be fixed and usually with American parts
steering box.
what did it fail on
loose. it can be bodged to pass
ask and i'll explain
these parts from this page (not all just the relevant for how screwed ya box is, do you need seals pr seals and bearings)
http://www.jimsautoparts.com/steering_parts.htm
POWER STEERING BOX MAJOR REBUILDING SEAL KITS
Contains all seals needed to rebuild steering box; no bearings included.
SP-PS2078
62-72 All Make & Model
$ 149.95/kit
SP-PS2079
73-up All Make & Model
$ 79.95/kit
POWER STEERING BOX MAJOR REBUILDING SEAL & BEARING KIT
Contains all seals and needle bearings needed to rebuild steering box.
SP-PS2078B
62-72 All Make & Model
$ 219.95/kit
SP-PS2079B
73-Up All Make & Model
$ 139.95/kit
OTHER STEERING BOX COMPONENTS
SP-2325
O RING SEAL PKG (seals for valve where power steering hose hooks up to) 2 Piece kit
$ 34.95/pkg
SP-PS8553
Upper Power Steering Shaft SEAL (where steering shaft goes into steering box)
62-76 All Make & Model
$ 43.95 ea
now stuff in red is what i think......that probably has no real bearing on truth cos i don't know your box but point whoever is building it to that page and they can get stuff if they need to from any Mopar performance supplier..... not just Jims auto parts. In theory your local chrysler dealer should be able to order in.....

but you will need part numbers and the patients of a saint....or just give them ya chassis number and watch them get a bit confused
keep in mind we in the UK are pretty good at bearings and seals JCB and landrover and london taxis all use imperial sized gear so what mopar performance sell you for 200 bucks may well be available from your local engineering/bearing supplies for little cash (or a place close to the place that rebuild ya box.) your box rebuilders will know what can be made to fit.
Sills
luckily are not complicated shapes. lower edge is flat panel the section across the door is hidden by the alluminium trim (if you have none i have 2 you can have, i'll think of a mutually pleaseing price )
patches, even huge patches are probably your best bet, and a competant bodywork man can make them.....the new stuff you can buy is just patches anyway and probably thinner than the patches a body shop will use...so unless you are lucky enough to find a complete car ready for chopping up, patch it. but make sure you get a body shop that is'nt a bunch of cowboys you want rust chopped out and a patch let in not tacked over the top
the oil filter setup will be an odd aussie one. not the same as the US one
the filter is identical but its mounting postion is not
(Kev or James or minty might chime in they have/had a aussie 318 and i dare say had differing solutions to oil filter mounting oddness)
not an issue
but a picture is worth 1000 words here...punt one up so we can see what bit looks bust
you can get replacement oil filter threaded pipe that goes between block and oil filter if it screws onto the block or a short 1 for an oil take off block which allows you to pipe the oil to a filter mounted on a filter head remotely. Any US parts place does these. more on that later
you can get remote oil filter heads to fit any filter you like.... i.e the option is there to junk the aussie thing
bolt a takeoff head to the block run rubber oil pipe from it to a remote oil filter and back.
Think automotive can help on this front
you want a mocal remote filter head and take off plate without themostat controled oil cooler take off for a v8 that has about 4 1/2 liters of oil in the sump. you don't need an unbustable Hi Pressure filter find out OEM equivelent so you can get it at halfords later
however
if you can take off the pipe .
then speedflow or Think automotive can probably make you one.
or if its brass and its out in the open and visbile there ain't nothing wrong with a standard domestic plumbing fitting. i had a 10mm olive style fitting in my fuel pipe for years with no grief
if its a specific short run of brass pipe that just fits between two things.
then you can probably get one made. TrevD on here could possibly help.
Core plugs get a chrysler 318 set of brass plugs your 318 is a 70s 318
from
US automotive or
WASP or
real steel or
hauser racing
rodley motors
A-Z of USA spares in watford (bob harmann automotive) are good guys
its the same as a US chrysler small block 318 in most areas
its not the early boat anchor
oil filter i have found that from a 1976-1986 landcrusier to be a perfect mix of weight filtering and anti flow back but again all chrysler small blocks take a filter that is identical to the orginal ford AFL1 filter also known as a Z9. If stuck a filter off a 80s volvo 740 will fit.
but may as well just get a filter from the guys you get the core plugs off
or TrevD has a supply of WIX filters that will fit at reasonable cost
Halfords do a nice set of build your own leads
but again you are going to be ok getting a set off the above suppliers
Spark plugs dunno the above suppliers will though
what does it have now?
take one with you to a proper motor factors. slap it on the bench and say hit me with 8. please. they will have a well thumbed book in the office out the back with equivalents listed
NGK yup
bosch yup
champion mmmmmm... nought wrong but they are getting a rep for being a bit crap but will do the job
you do not need anything special No irridium 3 prong platinum buttplugs, bog standard simple 60s style plugs, just check thread length is the same before putting them in, you might have got the saturday div on the counter at the motor factors...don't bother with halfords they will just say anything to get the sale.
may as well get a distributor cap while you are at it
agian small block chrysler cap for 1972 318 will do the job
Dave