I consider myself to be one of the few 'lucky ones'.. Bought used Webers off ebay and they worked brilliantly.

I installed a hi performance (unknown specs, but definitely at or near race spec). I first installed a known good set of SUs, and the thing just wouldn't run. Oh, it'd go okay, but not great. And I couldn't get it to idle at less than about 1500rpm. Tried and tried, but there was simply nothing to be done with SUs on that motor.

So, got the cheap webers (DCOE 40s), bolted them on. Damned if it didn't just start brilliantly, and with a tad of adjustment, settle into a nice, smooth 800rpm idle, and on the road... Oh My... The difference was absolutely night and day. I never thought a pushrod Volvo could do that!

Mileage... yeah. Dreadful. If I drove it like I hated it, it'd get 8mpg. That said, it's also easily as good on gas than SUs, if I keep my foot off it. But that's not easy.

My recommendation, try SUs first. You didn't say what the cam specs are, and that's really what makes the difference. SU's and really big cams just don't get along.

And agreed, a properly tuned weber downdraft can work just fine too. Surprisingly well. Or surprisingly poorly, depending on condition and how they're set up.

Basically, I've had good luck with SUs, Strombergs, Weber downdrafts, and the DCOEs.

I've had bad luck with SUs, Strombergs, and Weber downdrafts.

I got lucky on my DCOEs.

Start simple. Work your way up.

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-Matt I ♥ my ♂