1975 1.8 on twin carbs running poorly Options

[dt4]

My car is now registered over in the UK so I can enjoy it at long last, I took it out today for the first time other than the short drive to the MOT centre last month

It drove OK to a point but I noticed it was very slow to respond once in 4th gear, it felt very flat and not at all keen to pick up speed
If I shifted from 3rd to 4th at around 30mph / 3500rpm it was sluggish and a just over 30mph in 4th it felt like it was in the wrong gear and needed to down shift back to 3rd

on the hills it soon ran out of grunt and I was having to down shift from 4th to 3rd and even 2nd to get it to rev again and build speed
Setting off on a hill I had to really increase revs in 1st before shifting into 2nd otherwise it would bog down and feel like it was stalling

thoughts:
fuel?
timing?
other?

thank you
David

[Gint]

Sounds retarded (timing) to me. That's easy to figure out. Put a timing light on it. Could be dwell also, especially if it's slipping due to worn parts like the points rubbing block. BTDT Dwell meter. Check the basics and report back.

Ed asked about the clutch slipping. It does sound low for 4th gear at that speed. Worth looking at.

[porschetub]

Sounds retarded (timing) to me. That's easy to figure out. Put a timing light on it. Could be dwell also, especially if it's slipping due to worn parts like the points rubbing block. BTDT Dwell meter. Check the basics and report back.

Ed asked about the clutch slipping. It does sound low for 4th gear at that speed. Worth looking at.

(IMG:style_emoticons/default/confused24.gif) thought he had electronic pickup so don't think that will work .
I did mention ignition and valve setting a wee while back so IMO worth asking as this motor has been sitting for sometime and in reality a carb/clean resto.