3.0 webers what size venturis

[Alan.UK]

What size venturis have people used with a standard 3.0 sc motor with webers. Will 32mm be ok ?

Thanks

Alan

[jgparker]

I think 32mm will be OK and the drivability will be good, but for peek HP bigger might be the way to go. I'm still learning too...

[Steve@Rennsport]

Alan:

32mm ones are too small for a 3.0 litre engine.

Use 34mm or 36mm ones depending on cams.

[Wayne 962]

Originally posted by Steve@Rennsport
Use 34mm or 36mm ones depending on cams.

Right, the stock cams are so mild that 32s will work semi-okay, but as soon as you go to something hotter, you need to rejet to something bigger...

-Wayne

[Alan.UK]

Thanks guys,
I think with the stock 3.0 with webers I will stay with the 32s. I don't suppose you can suggest what jets and emulsion tubes I should use in the webers (in the standard 3.0 motor).

Thanks in advance

[Henry Schmidt]

If you have a late small port 3.0 80-83 the 32 mm venturis will work to about 5900 rpm. If you have a big port engine 78-79 the 32 venturis will tend to be small though out the range. A good place to start is: 155 mains, 180 airs, 60 idle, f3 emulsion tubes.
Good luck

[Alan.UK]

Thanks Henry

I will try that set up in the 80-83 204 bhp (euro) SC motor that I am doing for a friend. In my own 3.0 conversion that I doing at the same time I will use 34mm venturis maybe even 35 as I have a large port 78-79 3.0 motor but mine is having S cams and 98mm P&P. Do you suggest I start with the same jets for my car? I only ask as I am about to order all the new jets and tubes.

Thanks

Alan.UK

[Henry Schmidt]

The euro engine really needs the bigger venturis. It is a simple job the bore the venturis to the size you need if larger ones are not available. Even a small hobby lathe will work.
The jetting on either will work for a starting point. It seems that jetting is mystical and there are no set rules went it come to final jetting of carbs in general.
Good luck

[Alan.UK]

Thanks Henry,

I think I will get them bored out to 34mm and use the jet set up you suggest. I will let you know how I get on.

Thanks

Alan.UK