1958 348 tri power main jet size?

[slimpick]

I am restoring a 1958 348 tri power setup. Does anyone know what the stock jet sizes are for these three carbs? I was able to find the jet sizes for 59 to 61 tri power in my shop manual, but the sizes for 1958 were not listed and the carbs (more specifically the venturis) are different for 1958.

I did check in the technical section and found where it should be listed - but the picture is no longer available.

Thanks for your help!

 

[ozzie7]

Here ya go..... looks like the venturi's are the same as the others.

 

[oldskydog]

Here's an updated link for the tech section on 58 Tripower specs.

 

[wristpin]

I rebuilt a '62 348 tripower setup a few months ago. I used 60's on front and rear carbs and a 62 on the middle carb. It runs perfect. More by luck than design probably. If you need to buy jets and do get some...MAKE SURE they are not for Edelbrock or Holley. I bought several pairs from O'Reilly and they checked to make sure they were correct thread and size. They werent. My suggestion...look online....theres a business in Missouri, SE of KC that sells main jets...call them and order them unless you want to waste time like i did.

 

[Clint]

I have 61's in all three

 

[303Radar]

Am curious as to what elevation you're at/the car will be based? If it's over 5,000 ft, you'll want to make sure you don't run too rich.

 

[chuckl]

I live at sea level. I have 55's in all three carbs in my 61 348. Am running 91 non-ethanol with 10.5 CR. Seems to be a very good balance. All 8 plugs are correct color--no detonation/pinging. Runs good. I tried 61-63-61. Much too rich.

 

[slimpick]

Thanks for all the info! These data sheets are exactly what I was looking for. I also got a hold of Jon in Eldon, Missouri. He said a lot of people are running .059 in all three carbs. I will probably start with 60's in all three as a baseline.

 

[427John]

Anybody have insight to chevrolet's logic of staggered jets,when it appears that best results are obtained from same jets in all 3 carbs?Could they have been jetting for worst case scenario of car full of luggage and people going 75 mph across the arizona desert mid afternoon in august with poor quality gas?And what effect would that have on how it runs in best case scenario?

 

[rstreet]

Nah they were set up for the gas at the time
Robert

 

[MRHP]

You will likely have to use different jets due to today's fuel.