I was sitting around bored the other day. I have a couple extra Nikkis laying around. One is a 79 model and one is an 83 model. I noticed that the top section has a wider primary barrel porting around the choke plate than the 83 has. About 3/4 of an inch or so just from eye balling it.

Can I put the 79 top onto an 83 bottom? Do all the vacuum ports, fuel lines, and all that match up to the 83 float bowl section? Can I use an 83 gasket when doing this?

The whole idea here is that the 79 has a bigger port which SHOULD mean it flows more air correct? I'm just wondering if there is some sort of Nikki tuning trick here.

 

the 79-80 carbs are a little different, but some stuff still swaps over. 81-85 are mostly the same.

the 79-80 carb top is bigger, but does not flow as well. memo on that is really old (c1995), but still applies.

if you are not receiving memo's it might be your TPS cover sheet

 

There's a number of vacuum routing and porting differences thru the years on the Nikkis, most of which are primarily smog-related. They also are jetted differently by year, and by application (delivery location and trans type). Mixing and matching parts would be challenging unless you're really up on the variations. Also, design of the vacuum diaphrams, dashpots, etc exterior stuff changed over the years, too.

IIRC, Sterling has shown that the smaller air horn on the later Nikkis is actually preferable for reasons having to do with air velocity over the venturis.

Also, If you've got no use for the 79 carb, and it's in good shape, I might be willing to take it off your hands (if it's equipped with vac-operated power valves). I'm hunting a clean spare for my 80.

 

The larger primary mouth on pre 81 Nikkis doesn't help velocity. The smaller mouth on the later Nikkis already flows more than the 2 bored primaries of the 465 Sterling.

 

The extra carbs are both kind of in pieces. I was playing around with them... I would be willing to sell every carb part I have for a reasonable price. I just don't remember what came from what model as far as exterior pieces go. They should have every part except the fuel rail may be missing a piece if I remember right.

 

PM me some photos, especially of the inside of the bowl covers, and we'll see if we can reach an accord. Sorting out mixed parts might be pretty painful, but who knows? It keeps me out of the bars... (grin)