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305/350 jetting spec. for a q-jet

Justin Fleming

Justin Fleming

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I have an 86k5 (305) that I transplanted a 350 into this past month. Any how I have been sorting out this q-jet and I am getting closer and more efficenct with this carb. I was wondering if anyone has the baseline jet numbers that came in the 305 and base line jets that came in the 350.

Currently I am running the carb off my 305 on the 350 however i have added the G hanger and the DR rods wich did help but I am still getting the q-jet bog when going into passing gear. I have been through all the tuning from the q-jet books, tuneing threads etc. When I tighten the spring preload on the sec. air valve it gets better but the truck is more slugs, so I know that I am creating a lean condition when the air valve opens. I am thinking that the 350 carb has bigger mains and I need to go that direction....

From a dead stop there is next to no bog as I am getting that extra pump shot that helps with that lean condition and your not pulling as much air at that point....
 
"Just my opinion", Ditch that quad. and get a holley truck avenger or the new summit carb. Get vac. secondaries with elec. choke, let me know what your maximum rpm is going to be and I'll tell you what size of carb. to go with.
 
Disredgard post #2. The quad will be far superior offroad and when you get it tuned in, it will stay that way. Somone on here will point you in the right direction, as I'm about where you are when trying to get one of my Quads perfect.

Good Luck
 
iirc, there's a dozen jet sizes.... as to which is run in a 305 vs 350, not sure... I'm pretty sure I have one disassembled from a 350 somewhere... if i come across it this weekend, i'll check the jet size...
 
My Chiltons has every conceivable measurement - except jet size....:doah:

It's broke down by year and carb number, not by engine size...

I have taken my q-jet challenge personally also. There are too many running great for me not to be able to do it....
 
What gears/tire size are you running? You sure it's the carb?
 
Kenny78 said:
Disredgard post #2. The quad will be far superior offroad and when you get it tuned in, it will stay that way. Somone on here will point you in the right direction, as I'm about where you are when trying to get one of my Quads perfect.

Good Luck
Click to expand...

I concur. My experience is mostly with TPI (born in '88 doesn't give you a lot of carbs to grow up with). However, the dozen or so 40+ year old mechanics that have been teaching me since I was 3, have always agreed that q-jets were the best out there. They're the most efficient and handle off-camber the best by far. They're just more complicated to adjust properly and hence get a bad wrap due to many guys not understanding how to tune them properly.

I'm planning on smoking ribs and supplying beer while one of these old farts teaches me what they now as soon as I get the tank back in my truck.
 
yea pretty sure.....it just has standard tires on it for snow plowing, and 308 gears....
 
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