Holley 3 Barrels - Opinions wanted

[Drew Pojedinec]

For sure George, for sure.
Point was not to judge by cfm alone.

[1967 XR7 GT]

...once you figure that out they are a top notch carb for street/strip applications

I've never heard that. If the 3160 was the hot ticket, Holley would have made a bunch more and would still be making them.
I'll never build another carb'd motor, but based on input from others, a 3160 would not be on my list if I did. They were intended and used for big inch motors where finesse and driveability were of no concern. With poor secondary signal control, they were still outclassed by properly tuned 4150s and 4500s.
That said, I'm only repeating what I've been told by others. I've never played with one. That's how humans progress. Work with what has been proven to succeed and not replicate failure of others.

from what I heard (so take it FWIW), the 4500's replaced the 3 bbls because the 3bbls were more expensive to manufacture, not because of any shortcomings in the 3bbl. I have 2, so I may be biased. Then again, I also have a 4500, so....

Back in 1964 Chrysler had Holley make the 1st 950 cfm 3 barrel List #3085 for their Nascar Hemi, but it wasn't till around 67 that Holley released them for public consumption till around 69.

The only thing wrong with the 3 barrel are tunning issues, like any other carb out of the box, issues Holley never addresed, they just moved to the 4500.

[1967 XR7 GT]

Tuning tips I learned after I had picked up my 950 3 Barrel, as it turns out the correct front metering plate was swapped out, the correct ones are #5615. I tried finding one and couldn't, but I did find a metering plate from the 1964 Chrysler 950 list #4328.

The tuning issues of the 67 & later 950 & 1050 3 barrels, were not present in the 64 950. During my research It was mentioned why Holley just didn't copy the tuning of the earlier 950, something about meeting smog requirements in 67.

The 67 and later 3 Barrels issues were pig rich idle and a bad bog.  The fix is to open the PVCR's on the 5615 blocks from .040" to .070", as they are .093" on the 64 blocks because of the PVCR size is affected by the emulsion tube in the main well, where the later 5615 Blocks don't have the emulsion tubes.  For reference, the Holley 850 dbl pumper pri metering blocks PVCR's are .070", the differences between the 850 block and the 950 blocks are the 1964 950 blocks have E-Tubes in the channel and require a slightly larger PVCR to make up for the flow restriction caused by the E-Tubes. Primary tuning and jetting would be as you would any 850, secondary tuning and jetting would be as you would any vacuum secondary carb, like choosing the proper vacuum pod spring tension for opening the secondary then jetting as needed.

[frnkeore]

The mechanical secondary modification for the 3 barrel and the 3310, consisted of a tube, with a Y at the end. It pressed into the accelerator pump nozzle and extended across, to the back of the air horn. You drilled two holes, one on each side of the air cleaner stud boss, for the Y to feed the secondary's and you had to used the 50cc pump diaphragm. There were kits listed for them and I have seen quite a few 3310's, with those holes in the air horns, over the years but, the Y adapter missing.

When they came on the market, the 3 barrels where fairly cheap (at least in So Cal) and the 3310 was very affordable. I bought 2 of the 3310's for a MT, cross ram manifold, in '68 or '69.

Frank

[1967 XR7 GT]

The kits not only had the shooter that extended to the secondaries, there were 2 half gears that made the secondaries mechanically open 1 to 1 with the primary, with the vacuum canister removed.   I think the kits were a bandade because people couldn't properly tune them.

The mechanical secondary modification for the 3 barrel and the 3310, consisted of a tube, with a Y at the end. It pressed into the accelerator pump nozzle and extended across, to the back of the air horn. You drilled two holes, one on each side of the air cleaner stud boss, for the Y to feed the secondary's and you had to used the 50cc pump diaphragm. There were kits listed for them and I have seen quite a few 3310's, with those holes in the air horns, over the years but, the Y adapter missing.

When they came on the market, the 3 barrels where fairly cheap (at least in So Cal) and the 3310 was very affordable. I bought 2 of the 3310's for a MT, cross ram manifold, in '68 or '69.

Frank