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I am about to install a pair of 72' su's into my 74.5 260. Can anyone give me a run down on what is involved as far as removing, replacing and blocking off of the exisisting equipment goes. Any help at all would be greatly appreciated.
Thanks,
Adrian
 

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Adrian , Need more info. My 73 is running with all emission stuff removed. It was this way when I bought it .The car was running like crap, because the young man that diddent know a wrench from a screwdriver , t hought he was the great tuner. I now have a 240 that runs like a watch , after valve adjustment , '79 elect. ignition , set of NGKs . She had SUs but grossly out of tune. If I were to do what you are doing I would keep the airpump if it is in good cond. if not pull it. You need a vacume line from the manifold to the dist. [provided by the minifold and the SU] I would find a early type aircleaner for the carbs [according to the performance guys the best way to go is with the stock type air cleaner with a K&N filter] If you do pull the air pump you must plug the holes in the exhost manifold. Thats all that the engine needs . for spicific questions send me a e-mail and I help you with what I can . Gary Portland Ore. P.S. If you have the intake from your 260 and it is marked 36 keep it and use it ,supossidly, that one will yeald an aditional 10 hp.
 

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Here's some help...

1. Scott the former owner of ZTherapy has had flow tests done on the N36-there is no reasonable HP gain for a street driven vehicle. I had the N36, but didn't have anything to compare it to.
2. The '74 air cleaner will not work unless you buy adapters. If you use the '74 air cleaner half of the venturi will be exposed to the elements. Get a cold air induction set-up or a 71-72 air cleaner.
3. Depending on how environmentally friendly you want to be, you can eliminate almost everything. I would however, leave the PVC valve-it helps keep your oil cleaner.
4. I had an early '74 which has the same setup and put SUs on mine. The pic below will hopefully help you out. I had nearly 9000 miles on this setup and had no problems.
5. Your balance tube will work if you plug things off-if you want a cleaner appearance you can get the balance tube from a 71-72...just make sure you also get the linkage back to the firewall as it is a different length.
6. Make sure you get the linkage between the carbs-the flattops are different than the SUs.
7. You can use either the 260 spacer blocks or the 240 spacer blocks. The 240s are thicker and provide more insulation, but if you go with a cold air set-up you will need the thin ones.

 

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Some small things....

If you do get rid of the smog (AIR) pump, and remove the air pump injector gallery lines, make sure that you remove the injector TUBES that are buried down in the exhaust manifold. They stick down in the manifold maybe 1 1/2" or so and create a swirl/flow reduction. As written up in a Motor Trend article back in the 70's the tubes cause more restriction than the pump causes drag. You may have to pull the ex manifold to get them out since they are usually covered with crud. Leave the throttle closer attached, it will help prevent backfire a bit on decel and is no restriction to performance. I was looking over the old flow diagrams the other day and considering reinstalling the 'anti-backfire valve' also. It may correct the pop,pop,pop on decel by adding a bit of air to the intake. I have to look at it again to see if my theory is right, but it is something to consider.
 

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Re: oops..

Hey ZZZZZ.....

Sweet dude just the man I need some input from!!!

Have you experienced any problems with your SU's using the cold air intake set-up???
I am going for a cowl induction but someone before (here like last year...) said the SU's dont do well under pressure...Have you noticed any? Did you add weights to your SU's to keep them from rising prematurely (geez ya read that sentance and it sounds like the Z is impotent!! hehehe maybe some Viagra in the gas tank will boost performance!!!)

Anyway's if you have any input or suggestions let me know.....


Z ya later
Mike K
 
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