Carb heat shield

[tanny]

Will the stock heat shield for 3 screw SUs work with headers? If not, can the stock heat shield be easily modified to work, or is it easier to fashion one from scratch? Thanks, Victor.

[Sean240Z]

Victor,

I've also got a '73 240Z (though I have four-screw carbs). I installed a Motorsports 6-into-1 headers earlier this year and had to slightly bend the heatshield upwards to clear the rear pipe. After running with the headers, I realized that I had a fuel vapourization with the rear carb and made an extension for the heatshield under the rear carb (Pic of Heat Shield Extension). Not really pretty but effective. Since I added the extension, I've had no fuel vapourization problem.

The header installation was not wthout its problems. See the following thread for info on the Motorsport's header installation (MSA 6-into-1 Header Issues) .

Cheers,

[tanny]

Thanks for the reply. Then it looks like I can probably use the stock heat shield. All I have to do now is find one. I am taking off my triple weber set up and putting the round tops on instead. The problem is that I have been unable to get my webers to work really effectively below about 2500 rpm. At my altitude of 6500 feet the air is too thin for the venturi to work effectively at lower rpms, stumbling when accelerator is opened up quickly. The accelerator pumps are working fine and have messed with all kinds of jetting, but the bottom line is that I still have to open the butterflies slowly on takeoff so that it doesn't cough and sputter. So, since the rest of the engine is stock except for headers, the engine is not utilizing the potential of the webers(I am fairly certain I could solve most of my problems by installing a higher performance cam, but am not interested), and I would like to not have any more driveability problems and get better gas mileage, I will be installing the 3 screw round tops. Victor.