Rank: Member
Groups: Registered
Joined: 28/04/2012(UTC)
Posts: 420
Thanks: 3 times
Was thanked: 10 time(s) in 9 post(s)
|
Question for the carb guys.
I have a pre pollution 308 early HQ quadrajet on my 253 HG.
I want to change primary jets from 76 to 70’s to suit the 253’s smaller capacity.
Question is, Do I also have to change the 308 45B metering rods or will they be ok to stay?
Any help appreciated
|
j.williams |
|
|
|
|
|
Rank: Veteran
Groups: Moderator, Registered, Veteran
Joined: 1/03/2005(UTC)
Posts: 14,717
Thanks: 1 times
Was thanked: 512 time(s) in 488 post(s)
|
Just copy what is in a WB or VC-VK. Or buy a rebuilt carby off one of them.
From memory on an XT5 engine has the same secondaries for 4.2 and 5.0 but primaries are different. Look in WB parts book. |
_______________________________________________________
If we all had the same (good) taste, who would buy all the Fords? |
|
|
|
|
|
Rank: Member
Groups: Registered
Joined: 28/04/2012(UTC)
Posts: 420
Thanks: 3 times
Was thanked: 10 time(s) in 9 post(s)
|
Already has the correct CX secondary’s. A lot of confusing info out there but have sort of established that the blue 253 used 70 jet’s but can’t find any info on the correct primary metering rod’s. Edited by user Monday, 18 November 2019 9:06:07 AM(UTC)
| Reason: Not specified |
j.williams |
|
|
|
|
|
Rank: Member
Groups: Registered
Joined: 30/04/2005(UTC) Posts: 470  ![New Zealand]( "New Zealand") Was thanked: 15 time(s) in 14 post(s)
|
Hi HGV8 , 49-P is the metering rod you need. Thanks Mark. |
life is good in "Wine & Holden Marlborough " |
 1 user thanked justgm for this useful post.
|
|
|
|
Rank: Member
Groups: Registered
Joined: 16/04/2014(UTC) Posts: 768 Location: Victoria Thanks: 1 times
Was thanked: 49 time(s) in 47 post(s)
|
I suggest you talk to Mick at MLP Carburettors. You will get the right answer.
|
|
|
|
|
|
Rank: Member
Groups: Registered
Joined: 6/07/2019(UTC) Posts: 379 ![Australia]( "Australia") Location: bayside Melbourne Thanks: 237 times
Was thanked: 28 time(s) in 28 post(s)
|
Originally Posted by: justgm  Hi HGV8 , 49-P is the metering rod you need. Thanks Mark. correcto... the 'blue' 2fiddy3s with Quaddies used these don't use the 45s, a .045" rod has a rod diameter of .045" (and a small diameter "power tip" of .026") The larger (.045" or .049") section of the rod is positioned in the metering jet during light throttle operation and needs to be matched to the primary jetting used on whatever engine. A 45 rod is wrong size hth |
Club circuit racing...the best fun you can have with your pants on |
1 user thanked Smitty2 for this useful post.
|
|
|
|
Rank: Member
Groups: Registered
Joined: 6/07/2019(UTC) Posts: 379 ![Australia]( "Australia") Location: bayside Melbourne Thanks: 237 times
Was thanked: 28 time(s) in 28 post(s)
|
Originally Posted by: HK1837 Just copy what is in a WB or VC-VK. Or buy a rebuilt carby off one of them.
From memory on an XT5 engine has the same secondaries for 4.2 and 5.0 but primaries are different. Look in WB parts book. HK... the secondarys use a different coded rod .. CX (4.2) v DP (5.0) on blue/silver/black XT5 Improved Performance engines but actually, a CX rod is the better of the 2 GMH used. I use them in 308 Quaddies I build as they have a better 'power transition' to WOT (aka less bog) |
Club circuit racing...the best fun you can have with your pants on |
|
|
|
|
|
Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.
