Well, I will be picking up a fresh reman/rebuilt carb tomorrow. I want to tear it down and make sure it has the proper size jets in it before I install and try to tune it.

I have a 79 F250 with a 400. All stock aside from a new timing set, advanced 4 degrees. EGR blocked off, and dual exhaust.

Not looking for the most HP, just the easiest to tune/drive, reliability, and MPG if possible.


Thanks!

 

TTT, anybody?

 

Rubenk, your 2150 carb should have a circle embossed on the
driver's side of the float bowl with the numbers '1.21' imprinted
inside the circle.

The stock jet size for this carb is #56.

You can check the jet size by pulling the top off the carb, and
looking inside with a flashlight and magnifying glass; no need to
remove the jets themselves, the number will be visible.

Good luck,
TLR

 

Thanks TLR!

 

Turns out the carb the guy had was different than the 2150 I already had on the truck. But it was in excellent shape so I went ahead and picked it up.

A little research shows it to be a autolite 2100 carb. It has 1.08 stamped on the side of it. Any reason this carb wouldnt work on my 400 when tuned correctly?

I didnt really want to try making this one work with no research so I pulled my current carb off the truck to determine its condition.

I looks to be in pretty good shape when I took it apart, i'd suspect a fairly recent rebuild(past year or 2). The jets in it had 56 stamped on them so I know those are correct, float level was correct based on a rebuild guide I previously read. Put it back together and went to start the truck to only have a nearly dead batter...will go back and jump-start it later to continue work.

I DID find a vacuum leak I was unaware of though. It looks like the stove-pipe choke was broken off and i'll need a new one. I'll make another thread on that though.

 

Hi Reubenk,
Youir 1.08 Autolite is a 287 cfm unit, compared to the
1.21 Motorcraft being 351 cfm. I wouldn't use it on
a 400; it's just too small.

Sounds like you've gotten the original working fine.....

Just a heads up on the gasket:
If you're re-using the carb gasket, watch out for vacuum
leaks around it. My experience has been that they tend to
leak after the carb has been off and on several times.

 

Thanks TLR, check my other thread on the vacuum leaks :P Ended up replacing both gaskets, and disassembly of my original carb revealed that the needle valve was not clipped onto the float so it was just doing whatever it wanted....def not good.

Good info on the specs for those carbs, I figured it was too small to really run right.