what is best or better opinions please

Is the engine worked or stock ? what do you want it for street/race/daily driving ? Su's are a good option if you want to do sumtin cheap and effective, where webbers are alot better and alot more expensive .
Tye

go the SU's cheap and effective power. i have them on my A15 and she runs very well.
cheers ty

Define 'better' in your application.

SU's, or even better, a stock Hitachi GX induction will start easily, run smoothly, pull well, get reasonable, even good fuel consumption, & all at a reasonable price. They are better suited to engines in a relatively mild state of tune & you will love them if they are in good condition & correctly tuned.

Webber/ DeLorto/ Solex carbs tend to be more expensive, more difficult to tune, & because of their larger throttle bores, at one per cylinder, they are frequently more suited to the larger engine capacities &/or engines in a higher state of tune.

They produce very little manifold vacuum, so the vacuum advance would have trouble kicking in, even if they had provision for ported vacuum, which they don't, so fuel consumption at highway cruise is higher than for the Hitachis or SU's on that basis alone.

So the decision is simplified a little if you remember that Hitachi/ SU's would provide more joy on an engine in a milder state of tune or a regular driver.

The Webers etc would be better suited to a higher performance engie & an owner with more disposable income.

Me? I used a GX instalation for over 15 years & still swear by it.

dont you have to tune the su's to the weather tho?

Quote:And SU's are different from other carbs in this regard because, .............?

A carburettor is just a mechanical device to mix fuel with air in the correct proportions. Some carbs are more complex than others & do a better job, but the one thing that most carbs can't compensate for is atmospheric pressure & humidity. [The weather]
Really cold days at low altitude will have higher atmospheric pressure, & when you are hot & high, the perssure will be less.

A variable venturi carb, like SU's & the similar looking Hitachi's, control the size of the venturi according to the relative vacuum in the manifold & this in turn controls the gas velocity across the jet. In effect, it more or less stabilises the gas velocity, allowing a more stable mixture control when compared to fixed jet type carbs. [at least, that's the theory]
My Hitachi's had a jet adjustment under the carbs which was both easy to reach & easy to adjust without any tools, so if your exhaust gas analyser says that you're running a bit rich when you are at high altitude during a heat wave, then leaning it out on the side of the road will be a lot easier than with any fixed jet type of carb.

Conversely, next time you are in Death Valley [below sea level] during a snow storm, you can richen up your SU's or Hitachi's a little without any real drama.

Generally speaking, once your carbs [any carbs] are correctly set for the area where you do most of your driving, you will be fine.