Re: [Amc-list] WHat year 258's get water intake? Real world advantage?

[Frank Swygert <farna@xxxxxxx>]

The Clifford intake was made for racing, not driving. If you want a great driver 4V intake get an Offy dual plane. Offy makes a single plane intake too, so make sure you're getting the dual plane. It has a divider visible in the end of each runner. This produces better low end torque as it creates a smaller runner for each half of the carb, keeping intake velocity up. The secondary runner plane is a bit larger than the primary. 

Luckily Mark told me about his problems! I don't have any cold weather issues now, not after the engine warms up anyway. I made a 1/2" copper tubing heater for the intake. All I did was run a piece of soft tubing along the bottom of the intake with 90s on each end going up to connect a heater hose to. I used straps and screwed them through the bottom of the intake to hold the tubing on. I drilled holes for the screws, put a dab of fuel resistant sealer in the hole (#2), then used a self tapping screw. No vacuum leaks! The thing is a bear for about 10 minutes in freezing/near freezing weather, but runs fine once warmed up. You just have to plan where the ends of the tube come up to miss any accessories. I had to 90 out then up on one end.

I also thought about making a shield to attach along the side of the intake. That could be zip tied, wired, or clamped on. Extend the metal shield the length of the intake and down over the exhaust manifold. That would hold and direct exhaust heat up to the manifold. Wouldn't be as even as water heating though, and might get too hot in summer. 

I use a 390 Holley 4V carb. If you want more power get a 450-500 cfm. The 390 is a good economy carb, but not much more power. The main problem, however, is the very conservative cam. Just a little more cam makes a HUGE difference! I also have a 4.0L head and exhaust. They didn't make much difference with the stock cam either. All in all I think I ended up with about 15-20 hp, all in the upper rpm band (at cruising speed). It holds speed and pulls hills a bit easier, but no improvement at take-off at all. 

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Date: Tue, 3 Mar 2009 00:33:53 +0000 (UTC)
From: Wrambler <wrambler242@xxxxxxxxxxx>

What I wrestled with was getting a good all around tune out of a Clifford mounted without heat!

They are free standing aluminum and they run COLD! In HOT and I'm talking true hot weather the intake is ok.
But anything below about 70-80 degrees and the aluminum intake dissipates heat so fast the fuel drops out of the mix in normal driving! Not something you will want in your J10. You can tune it to run WOT and drive hard, but off idle tip in and normal cruise SUCKS. I tried everything I can or could think of.  I had stumbles, poor idle etc, It royally P.O'd me big time.

  If you are running a clifford or any other open plenum I would recomend you install heated water to it and have it run through the intake. Should make it much easier to get a good tune and be much more fun to drive!  What I wish I would have realized or looked for is that you can get 4bbl carb spacers that are heated! My intake was ancient so it did not have water provisions. 
  Frank has it now. I don't think he is particulary in love with it either!

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
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