Does anyone have experience with this offenhauser 2x4 intake ?

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340dartsport73

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I just bought it this weekend at mopars in the park. Any experience with it good/bad or is it just a wall hanger.. Bottom # is 5488 and the runners are #5497

20230603_191939.jpg
 
The 5488 comes up as a '64/'65 only (different bolt size and angle than '66 and later smallblocks) 273 (small port) intake. Still available new.
The 5497s are just universal "cross ram" adapters that they sell to convert a standard inline dual quad into a quasi-crossram. Also still available new.
Ran a similar Offy inline for the '66 and up 273/318 years ago with dual Comp Series Carter 500s on it- performed okay, and street drivability was surprisingly good, but I wouldn't say better than a well sorted single four. Looks cool, though!
BTW, I didn't have the crossram adapters, just the manifold; so I can't comment on how it performs with those on it.
 
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Low end tq would be horrendous......
You are essentially adding two huge plenums under the carbs.
 
Best thing to do with that manifold is to mill of the tops and weld a 1/2” thick 671 blower adapter plate. Build yourself a nice early blown 273. It’d already have a forged crank, solid cam and adjustable rockers. Cool.
 
I have the same intake #5488 without the crossram. Its mounted on our 67 273. Heres a thread I started on it.
The carb linkage and throttle cable will be the hardest/priciest. I made my own linkage.

340dartsport73 said:
I just bought it this weekend at mopars in the park. Any experience with it good/bad or is it just a wall hanger.. Bottom # is 5488 and the runners are #5497

View attachment 1716098236
Click to expand...

20230506_202856.jpg
 
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I have one, got an aluminum bit for a dremel and hacked the bolt flanges, got me some spherical washers and will run it. Gonna compare to the eddy d66 which is a dual plane and an rpm airbag. I'm probably just going to run the weiand 1995 tunnel ram after all is said and done though.
 
The DQ I bought was close by and I thought it was cool, so I bought it. Initially I planned on using for 340, but nowhere near enough meat on flanges for the larger ports on 340 gaskets.
It will be more "impactful" once it goes on the Commando.
 
4spdragtop said:
The DQ I bought was close by and I thought it was cool, so I bought it. Initially I planned on using for 340, but nowhere near enough meat on flanges for the larger ports on 340 gaskets.
It will be more "impactful" once it goes on the Commando.
Click to expand...
I was thinking that I could build up the outsides of the runners and hog the insides out as needed.
 
340dartsport73 said:
I just bought it this weekend at mopars in the park. Any experience with it good/bad or is it just a wall hanger.. Bottom # is 5488 and the runners are #5497

View attachment 1716098236
Click to expand...
Looking at that set up I cannot help but think that the back left pair of cylinders and the front right pair will run richer than the others mainly due to the fuel that finds itself on the manifold floor as it leaves the carb. I personally would be more inclined to try standard spacers on each opening. Fuel doesn't like a complicated path into the cylinder.
 

4spdragtop and his pictures explain it all. Although places may claim that Offenhauser will work on the 340 360 the pictures show reality. The manifold was designed for the 273. Then the 318LA came out and it works fine with the 318 (Uses a variation of the 273 heads.) The 340 comes out in 68 and its ports are SIGNIFICANTLY larger than the 273/318. Thus the problem of insufficient sealing of the Offy on 340/360 heads.​

 
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