plumbing confirm...

[shaun]

I'm about to that point to plumb fuel and water and want to get some feed back as to what I'm thinking should be run...
The fuel tanks as well as my fuel pump (Mallory 110 marine) look to be setup to receive a -8 fitting, so I'm going to assume that running the hole fuel system in -8 up to the carbs (2 x Holley 660's) is what i should do.
As for water, I have a pressure reducing valve (3/4" Watts N55BUM1) then down to -10, then split into two -10's that will go into the block. Then -10 out of the manifold to the dump. For the headers I'm thinking -10 also, just because i think my Bassett T valve is -10 (need to check to be sure).
My understanding is -10 is 1/2" NPT and -8 is 3/8" NPT
This all sounds/look right?

[Taylorman]

T valve is -8 1/2. -10 is 5/8. You should use 1/2 for everything.

[superdave013]

T valve is -8 1/2. -10 is 5/8. You should use 1/2 for everything.
-10 is 5/8" O.D. and it is the closest to 1/2"NPT with an I.D. of 0.56".
-8 has a 0.43" I.D.
Some run 8 and some run 10. I run -8 to the headers if they are using the tee valve. If they are using a banderlog of some other type of window switch I'll use a -6 to the headers.

[502 JET]

-8 will supply you with more water and fuel than you can use. There is no reason to run -10 to the headers, you only need a trickle of water feeding them. Run -8 to your fuel regulator and -6 out to the carbs.

[396_WAYS_TO_SPIT]

I run -10 for water and -8 for fuel.

[jrork]

I run -10 for water and -8 for fuel.
Ditto for me. No problems whatsoever after 3 years

[zudnic]

T valve is -8 1/2. .
Learned that Sunday on Lake Shasta after getting a nice pin hole water leak. Holiday Harbor marina repair shop guys hooked me up with some hose for $3 bucks.... Ask for extra from what you need was pretty simple fast instal with water coming in from the transom. :D

[jbone]

I run -10 for water and -8 for fuel.
Ditto for me too. I have water jacketed headers though.
J

[shaun]

thanks for the replys... fuel will be -8 and my header lines and T valve look to be -10 so all water after the regulator will be -10.

[superdave013]

are your headers water jacketed or water injected? I've never seen a -10 tee valve from Bassett.

[VAMI]

The numbers -6 -8-10 etc are in 1/16's so 6/16 reduce to 3/8 and so on.

[superdave013]

The numbers -6 -8-10 etc are in 1/16's so 6/16 reduce to 3/8 and so on.
That gets you the o.d. of a tube. A 3/8" hardline is a -6. The inside of a -6 braided hose is .34", -8 is 0.43", -10 is 0.56", -12 is 0.69". Now the nipple of the hose end is even smaller so if it really matters use the -#/16 method and bump it up one size.