What year did the bypass hose size change?

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Krooser

Krooser

Building Chinese Free Engines since 1959...
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Working on my ' 74 318...the bypass hose I bought fits the '69 intake nipple but is too small for the water pump connection.

This is a mix and match engine using my available water pumps...all three pumps that I have feature the same larger water pump nipple.

So what year fixed this issue?
 
So my intake is a '69...water pumps are later.


Since there isn't any way to change the as-cast larger water pump fitting I have to figger out how to adapt/reduce/enlarge the intake to fit the later bypass hose fitting.

Maybe just fitting an early water pump to the engine would be simpler because the lower hose is a larger 1 3/4" too!

I was going to have the rad lower inlet moved to the passenger side to accommodate the newer pump...buying a an early pump would be so much easier...BUT

There's the other issue I may have screwed up... I think I bolted on a harmonic balancer for an internal balanced engine...this is a late '73 built engine with a cast crank. Timing cover is a later deal with the marks on the left. If I use an early water pump the cover is wrong...geez....
 
The pulleys are much different between the cast and aluminum water pump too. So is power steering pump.

The newer aluminum water pumps (70 up) are also about 3/4 inch longer than the cast pumps. This can cause radiator clearance issues. I swapped from the old water pump to the 70 up pump. Lots of collateral damage on everything else. Wish I had not done it.
 
Krooser said:
So my intake is a '69...water pumps are later.


Since there isn't any way to change the as-cast larger water pump fitting I have to figger out how to adapt/reduce/enlarge the intake to fit the later bypass hose fitting.

Maybe just fitting an early water pump to the engine would be simpler because the lower hose is a larger 1 3/4" too!

I was going to have the rad lower inlet moved to the passenger side to accommodate the newer pump...buying a an early pump would be so much easier...BUT

There's the other issue I may have screwed up... I think I bolted on a harmonic balancer for an internal balanced engine...this is a late '73 built engine with a cast crank. Timing cover is a later deal with the marks on the left. If I use an early water pump the cover is wrong...geez....
Click to expand...
www.forabodiesonly.com

1'' bypass hose issue

i picked up a weiand xcelerator sb intake, it has a 3/4'' bypass hose fitting.my water pump and intake have 1'', is there an adapter fitting for this, if i can even get the old fitting out of the weiand
www.forabodiesonly.com www.forabodiesonly.com
 
Yea all 318s are neutral balanced internally. At least you’re ok there.
 
If using the 70 up aluminum water pump with an intake that has the 69 and earlier smaller bypass hose fitting you have to use a 1" hose barb X 1/2" MPT fitting. You will have to use a brass fitting-the only thing that i have found. I like the clamp style that is smooth with a bead on the end. There is a place that used to have these but they have been discontinued. So the only ones that are available are the barbed type. When I use one of these I grind the end rib off to shorten the fitting, otherwise they are a little long. You can get them at fittingsandadapters.com, part number MPT-16-8 at 7.36 each. Home Depot says they have them, you can check and I found them on Ebay-auction number 185247657448 at 10.48 each. Again 1" hose barb X 1/2" MPT. I like using brass fittings on aluminum intakes-they don't rust and you can remove them easier if need be.
 
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