Dellorto 40 DRLA and manifold question

[Nikov]

I have a pair of 40's and manifolds, the query I have is; the carbs are 40mm where they meet the manifold but the manifold throat is 48mm which results in a sizeable step.

Do I need manifolds that flow smoothly from the carb or will these ones be ok? 

[nicolas]

matching manifolds would be best. these will create a pocket where the air/fuel mixture could stall.

[Nikov]

matching manifolds would be best. these will create a pocket where the air/fuel mixture could stall.

Yeah that's what concerns me Nicholas 

[Torben Alstrup]

The difference is very minor.
Some people claim the intake vacum at idle gets too low with the larger manifold. I use to say that if they have this problem something else is the matter. I have used these manifolds right down to 1200 cc. and have only noticed a slight hesitation off idle when large duratrion cams are used too.

T

[Nikov]

I'll give them a go and see what happens.

Cheers

[Zach Gomulka]

There were specific 40mm manifolds made back in the day. Hard to find, but they're out there...

[Jesse Wens]

you can get new ones at CSP
http://www.csp-shop.com/cgi-bin/cshop2/front/shop_main.cgi?func=det&wkid=77828856538&rub1=Engine&rub2=Fuel%20System%2CIntake%20Manifolds%2CIntake%20Manifolds%20Type%2D1&artnr=19845a&pn=0&sort=0&all=

I, ve used them also because the step seemed rediculous to me.

Jesse

[Garrick Clark]

I'm using some of the 40mm  CSP manifolds to match the 40mm dells.
They are worth buying.

[markvo]

You can use Gene Berg 40 idf manifolds