fuel injection
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Senior User
Joined: Apr 2004
Posts: 119
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From: nj
fuel injection
hey wats up i have an 89 bronco with a mass airflow conversion. msd ignition. the block is a 74 302 bored out .030" over spec. also have a crane cam with .495" lift. i bought a 5.0 upper and lower manifolds from a junkyard for 90 bucks. because i dont want to keep the motor carburated i painted the manifolds up nice and cleaned them and installed them. turns out the passenger side of the manifold leaks antifreeze front and back while the driverside seals tight i beleive the lower manifold is warped. and was wondering what kind of intake manifold i can put on this motor. motor has stock heads and was blue printed 10k miles ago
Hotshot
Joined: Jul 2002
Posts: 14,285
Likes: 12
From: Bend,OR
when you bolted down the lower intake did you start in the middle and work your way out in a cross pattern. just like tightening your lug nuts on a wheel. also you need to put a light beed of silicon down at both ends of the intake to seal it properly. you might have also messed up the lower gasket during install. its also possible that your motor is to old for the efi intake due to the heads that are on there. might look for some E7's
Lead Driver
Joined: Sep 2002
Posts: 9,182
Likes: 12
From: Gateway to the West
I'm with Kem on the concern over the bolt tightening pattern and seal situation. The lower plenum should fit the '74 heads. My memory could be rusty here but 74 should be the absolute oldest you can go and still have the EGR and Thermactor air injection passages in the right place (inside the heads). But then there may be other differences that I am not recalling right now.
Check your tightening order and make sure the gasket(s) didn't slip during the install before assuming problem is the mate between the components.
Check your tightening order and make sure the gasket(s) didn't slip during the install before assuming problem is the mate between the components.
Lead Driver
Joined: Sep 2002
Posts: 9,182
Likes: 12
From: Gateway to the West
3/8" bolts are 22-30 ft-lbs.
5/16" bolts are 19-25 ft-lbs.
Remember to re check the torque after reaching the last bolt starting over at the first bolt. Once the outer bolts are tightened to the proper spec. the inner ones may need a tweak or two. I have never installed a cylinder head or manifold (intake or exhaust) wihtout running over every bolt at least three times (keeping the same tightening sequence each time) to be certain the torque spec. has been met.
5/16" bolts are 19-25 ft-lbs.
Remember to re check the torque after reaching the last bolt starting over at the first bolt. Once the outer bolts are tightened to the proper spec. the inner ones may need a tweak or two. I have never installed a cylinder head or manifold (intake or exhaust) wihtout running over every bolt at least three times (keeping the same tightening sequence each time) to be certain the torque spec. has been met.
Cargo Master
Joined: Dec 2003
Posts: 2,734
Likes: 38
From: Sunny Florida
The problem could be in the intake gasket. I'm not sure when ford changed the water passage shape but they did and I am pretty syre the 74 head will have a different shaped passage which should be shaped like and L and the later heads are more square shaped. If you used the gaskets for a 74 head then you will have mismatch in the gasket to sealing surface.
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