Best way to eliminate manifold water passages.

[68Datsun510]

WHats the "preferred" way to eliminate the water flow from the head to the intake manifold on an L motor? Gasket without holes, or tap/thread the manifold and block it with a plug???

[Skib]

I plug the manifold

[banzai510(hainz)]

1/4 inch pipe plug.

1/4 inch is the allen size. go to a good hardware store and theyll gove you the correct tape for it.

If you have a stock head with the stock water passage hole all you need to do is run the tap. as the hole is already the correct size or close to it already so no need to hole size it for the tap.

 

 

my cheat sheet shows

1/4 plug NPT

1/4- 18 NPT

use a 7/16 drill bit if needed. If close to 7/16 just use the tap/

[datzenmike]

Keep it if possible. It warns up and drives better sooner with it. On really hot days with high under hood temps, or if you have a lot of radiant heat from a header, it actually 'cools' the intake. It keeps the intake air at a more constant temp over a wider range of applications.

[banzai510(hainz)]

I plugg them if using sidedraft carbs other wise I keep them stock(with a down draft for winter to heat the carb otherwise in cold claimates carb can freeze and ice up)

[68Datsun510]

It doesn't get particularly cold here, coldest we've EVER had was 16. Ave mid 30's for lows at worst. Im just wanting to avoid the whole, pull the intake, flood the garage with coolant crap. Thinking of just plugging the head holes and be done with it.

[docbainey]

Plugging the holes in the head is the way to go. If you plug the manifold you can still have water leaks and such.