1970 z28 correct fuel lines

maguyvr

Member
Feb 25, 2015
59
Woodland,ca
I'm trying to install the correct fuel lines back onto my 1970 LT1 350. The carb has been changed from the original 780 Holley to a 750 and has 3/8" outlet fittings on it. I ordered the OEM style 3 piece lines and block fitting from Camaro Central. The line from the pump to manifold isn't even close to fitting. Maybe it's bent? And then the lines that go from the block to the carb are 5/16" and the carb inlet is 3/8". I'm assuming that they were originally 5/16". Besides getting either a straight (or correct) line from the pump to fuel block, do they make a fitting for the Holley that is for 5/16" line? Thanks for any help you can provide!
 

Zspoiler

Veteran Member
May 6, 2012
4,365
Federal Way, Washington
You are going to starve your engine if you run a 5/16 line from the fuel pump to the carb.5/16 lines are generally return lines. .I would run a 3/8 line from your fuel pump to your carb, I believe that there are prebent lines out there.If not you can always make your own.
 

70 SS/L78

Veteran Member
Lifetime Gold Member
May 5, 2005
2,971
Rockford, MN
maguyvr said:
I'm trying to install the correct fuel lines back onto my 1970 LT1 350. The carb has been changed from the original 780 Holley to a 750 and has 3/8" outlet fittings on it. I ordered the OEM style 3 piece lines and block fitting from Camaro Central. The line from the pump to manifold isn't even close to fitting. Maybe it's bent? And then the lines that go from the block to the carb are 5/16" and the carb inlet is 3/8". I'm assuming that they were originally 5/16". Besides getting either a straight (or correct) line from the pump to fuel block, do they make a fitting for the Holley that is for 5/16" line? Thanks for any help you can provide!

All pre-bent fuel lines will still need tweaking & bending to make them work. I purchased 2 different line kits on my L78 and neither one of them worked without more bending.
As far as your fuel bowl fittings you should be able to get the 5/16 bowl fittings you need to work with your reproduction fuel line kit.

Contact Eric at Vintage Muscle car parts... [email protected]
He will have the correct black zinc bowl fittings.
 

giggity

Veteran Member
Mar 18, 2013
1,728
Pearland, texas
Ive recently been reading about 70 fuel lines, and apparently 70s came with 2 different sized fuel lines. 5/16 and 3/8. the routing for each should be the same , our cars did not have a return line, as far as I can tell they didnt have a coal filter, but ive read some posts that said some California cars came with them.

I wish you lived closer Id make you a deal on my factory line, Im putting in an electric pump, and using braided line, adding a return. I really have no need for the factory line, even though im using it for a return.
 

COPO

Veteran Member
Lifetime Gold Member
Sep 15, 1999
21,996
Ontario, Canada
Stock 70 Z28 uses 3/8 from the pump to the brass block in then the 2 outs into the carb are 5/16. If someone in the past used the Holley chrome straight line with the 2 fittings then this will all be 3/8 and you will have the larger fittings in the front and rear bowls.

Check out my website.
 

Matt69406

Member
Mar 19, 2017
34
All pre-bent fuel lines will still need tweaking & bending to make them work. I purchased 2 different line kits on my L78 and neither one of them worked without more bending.
As far as your fuel bowl fittings you should be able to get the 5/16 bowl fittings you need to work with your reproduction fuel line kit.

Contact Eric at Vintage Muscle car parts... [email protected]
He will have the correct black zinc bowl fittings.

I know this is an old post, but I have ran into this issue. Are the 5/16 inlet fittings supposed to be black? Fuel line kit I purchased has 5/16 male fittings, but my 1970 Z28 carb (list 4555) has 3/8 female. I'm guessing the fittings in the carb have been changed at some point. I am going to get fittings and just wanted to make sure the 5/16 was correct and also should they be black? Any input would be appreciated!
 

COPO

Veteran Member
Lifetime Gold Member
Sep 15, 1999
21,996
Ontario, Canada
Black inlets for the 2 5/16 lines. The rest was a 3/8 line.
82291E61-194A-403F-8E8F-5AA1E753E8A0.jpeg


DC1CBFE0-BE7D-4361-9C1B-C82D6BB68054.jpeg
 
Last edited:

l16pilot

Veteran Member
Lifetime Gold Member
Dec 13, 2004
2,264
Hurlock, MD, USA
1100 original mile 70Z, Van Nuys, 03C TH400 car....but I do not see why the fuel inlet fittings would be any different than other Holley versions on the 70Z. Look closely and you can clearly see the black finish. Could this have been a running change in production?
0.jpg
 




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