The Rochesters used on 308 past a certain point don't have the same linkage on the side for throttle attachment. The early LH and HJ ones do, ones with numbers: 7043283, 7043284 and 7045281 - these all have an adapter bolted to the side for the cable throttle if used in that application, but the plate is as per HT-HQ for rod style linkage. If you have a 17056280 or 17057294 (HX-HZ and LX) then you may have to convert it to a cable throttle or get another carby. You may also have a 253 rod and need a 308 one.

That is a blue 253 carby. What you are going to have to do is either make up a new rod or convert to a HJ cable throttle. Even if you make up a longer rod it may not have the right pull for that carb's arm above the pivot, the one off a HQ looks like the one in this ebay auction: http://www.ebay.com.au/i...e7adc1c79#ht_2355wt_1203

One of the later series after HQ (I think it was HJ) had a bolt on pedal which will bolt in where the HQ one is, just have to drill a round hole in the firewall in the right place and file it square, just copy off a HJ-WB for the location and size. Then use a HJ-WB Rochester cable, and you'll need the bracket for the manifold too, plus the one for the return spring.
As it is an auto, make sure you use the right vacuum port for vacuum advance, these carbs have both ported and full vacuum ports.

John is right, I have seen them done that way. I was thinking of a HT I did it to once. I have done a similar thing to a HJ with a HZ wiring harness where I made up a plate to bolt in where the HQ-HJ harness plug is, and put a hole in it for the HZ harness.

Yes. HQ pedal should unbolt, and from memory it was HJ that had the pedal bolted in, HX-WB are welded, but you can still use one of them, just have to grind it out and it has from memory the holes in it to bolt in. Just make sure you get the kickdown switch and bracket as well if it is different to your HQ one.