670 Truck Avenger carbs jets

[Maherpmj]

I know there are dozens of treads on jetting these carbs, but I have never been able to get a good answer on why Holley put 89 jets in the rear on these stock? Typical rule of thumb is 8 sizes larger if no power valve, not a 21 size jump . That Holley tech on their tech support didn't have an answer.

[Ristow]

because of the check valves in the metering block that allow it to run at "extreme angle". it changes the typical jetting of a similar size Holley.



notice the lack of high speed air bleeds on the secondary circuit. theres a check valve in there instead. same on the primary side. thats why the truck avenger has annular boosters and the street avenger-with its standard metering blocks-does not.

[babywag]

The last guy I knew that had one hated it.
Very poor mpg even normal driving.
He traded it for a 470 and was happier.

[asphaltrockdweller]

I had one (670), and ended up selling it off.
They take a whole lot of tuning to get right, and even then it was not fun. Kevin (FSJ78 I think?) has had one on his Chero, but did a lot of tweeking to get it to run well.
If I ever get the Waggy back on the road??? I bought EFI for it. I will use a cheap Holley refurb to get the engine broken in, but change over to the EFI system after that.

[Maherpmj]

Actually I set mine up like Kevin recommended from all his testing and it runs well on and off-road. Zero bogging and seems to pull strong throughout the power band. Never actually ran the carb with the 89s in the rear

[rocklaurence]

I had a TA 470 on my CJ5 and it ran great Off Road--on Road wasnt a concern.

[Ristow]

i had a 670 on my 401. it ran decent. the only change i made was it came with a 2.5 PV and had a bog on transition to power.



so yeah they can run fine. but if you are not off roading more than half the time there are better carbs to run.


people buy these for their daily drivers because it has "Truck" in the name.


i bought mine because of the annular boosters,not looking at the rest of the specs which would have revealed the annular boosters benefits are wasted on the check valve'd metering block.




for a daily driver i wouldn't buy a carburetor that didn't have removable air bleeds and idle jets. i used to retune holley 4180's in that fashion. best street VS carb holley made.