Hi,
Can anyone tell me when I should use Weber 40 and when to use Weber 45? I'm planning to replace the original carburator on my 2 liter Pinto-engine. The engine has only been cleaned up, painted and has had a new original camshaft fitted. Now I've been offered both a pair of used 40:s and a pair of used 45:s.
Are there any guidelines for when to use 40s and 45s?

/Johan

It's size of main venturi that counts - if you have a choke per cylinder there's a weber chart that tells you venturi size vs cylinder displacement & max power revs, I'll email you a copy if you want.
Cheers
Bob

If your going to go for big power latter, i.e. 150 bhp+ then probably best to go for 45, if not you can get the power out of the 40s. If you go 40 you will probably get more low end torque. I used 40's when i had my pinto and they were fine.