Offy 5970

Jegs sells the large log Offy setup for $336.

Will my Holley 1940 work for the center carb or is the orginial carb required?

Im just thinking about stuff.

8) it depends on what carb openings are used in the offy adapter. if they use the smaller 1.5" carb openings, then your holley will do fine. if they use the 1.75" openings, then you need a later carb.

A case where i forget that you dont know what I know.

My head is a 1970 casting.

I dont know if the carb is a 1.5 or 1.75 throat. I need to pull it and take a look.

The PO had a shop put the carb on.

I dont know if I have the LOM dizzy or not, I cant find any numbers on it.

That might have something to do with the car running like crap.

The Offy 5970 is for the large log.

HOwdy again bmc:

I just posted on your other query. FYI the Holley #1940 is a generic replacement carb designed to replace a variety of applications of the original Autolite 1100s as well as the later Carter YFs. It came in versions of 1.5" and 1.75" throttle bores, manual and auto choke, SCV and non-SCV. So, again, saying you have a Holley #1940 doesn't really tell us what is needed. Also know that the #1940s, in general were notorious for a rough idle, flat spots, hard starting hot and poor mileage. Most agree that they had a better choke system than the Autolites they replace.

The good news is that they were designed so that stock linkage, fuel lines and vacuum lines could be used, so that shouldn't be a problem for you.

For a 3 X 1 carb set up I'd recommend finding three carbs that are identical. The center card is the only one that will need a choke system. Also check with those who have gone this route for advice. Also, since three carbs will effect vacuum, make sure you consider the link between the main carb and the vacuum advance function of the distributor.

FYI- On the distributor, pop open the cap and look. IF you see two spring near the bottom, it is a Load-O-Matic, Spark Control Valve operated distributor. I'd sure recommend upgrading to a later system with centrifugal advance as well as vacuum.

Adios, David

hello i have used tree carter yf carbs. on a 70 head.




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greetzz JD

I just posted on your other query. FYI the Holley #1940 is a generic replacement carb designed to replace a variety of applications of the original Autolite 1100s as well as the later Carter YFs. It came in versions of 1.5" and 1.75" throttle bores, manual and auto choke, SCV and non-SCV. So, again, saying you have a Holley #1940 doesn't really tell us what is needed.

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David is correct. My car came with a 1940 carb. It was 1.5" with an SCV. I later bought another 1940 off of a member here and installed it after my 250 head swap. It was a 1.75" bore without the SCV. So post a picture and maybe we can help.