40mm is better for your setup as mentioned or smaller.

or ... ask PJZ for one of his race heads as you will otherwise need to upgrade to an oval port head or use bigger valves and ported normal round port head, springs, shaved for higher comp, good ignition, headers and a mild camshaft. to run the 45mm.

Peter has heads all ready done and way cheaper posted.

Most Datsun DCOE kits from Weber includes 30mm chokes I think. I would run those, as it will come jetted for it. It will run perfect on stock engine, with very very good throttle response.

If you decide to go with larger venturis for more top-end performance (which the A15 economy version may or may not need) then you size the main jets according to the venturi size. Venturis are chosen for desired airflow, and jets are chosen to maintain a 14:1 air-fuel ratio. Ask the vendor for assistance in choosing the appropriate jets for a stock engine. Besides the main jets you'll want all the other tuning bits (emulsion tubes, air correctors, idle jets, pump jets, etc).

For the 80HP A14/A15, the old weber 40 kit came with 33mm venturis for 6000 RPM performance. The base L16 (not the SSS) used the same.

For a stock A12, the weber 40 was recommended with 27mm venturis which apparently they don't sell anymore. So use the 29mm venturis.

OK, thanks. So 31mm chokes on a 40 DCOE. What about the jets? What number for main, idle, air, tubes, etc.??? And thanks again!

> would a single 45 DCOE Weber be a good choice for a bone-stock A15 economy version?

No. The round-port engines make max power at 5600 RPM, and to make a 45 work perfect it would need 31mm venturis -- but 45 venturis only go down to 32mm. 45 can work on an A15 bone stock economy version, but not perfectly.

40 DCOE by contrast can fit venturis (chokes) of 29mm to 36mm, so it is good for a mild or wild A15.

Remember, it's all in the tuning (starting with the venturies).

i run a 45 chocked right down on my mild a12. Goes good. But i would suggest a 40dcoe more than anything...

A 45 will be ok but 40 is more suited if you run small chokes in a 45 & jett it correctly it will be fine.

I would recommend exchanging the 45 DCOE for a smaller 38 or 40 DCOE. Peter

Hi guys! Happy New Year to everyone! This is my first post at Datsun 1200 Club! I was wondering, would a single 45 DCOE Weber be a good choice for a bone-stock A15 economy version? (Economy meaning engine with shrouded round port head and no mods whatsoever) Thanks for your advice