'73 240z flat top carbs dilemma

[Dadsun]

On 5/9/2020 at 8:06 PM, Zup said:

 

I wouldn't be spending money on a header until I found a true need for it. The header is immaterial to vacuum leaks. It might help with engine compartment temperatures, but until you've driven the Z hard enough and long enough to reach those temperatures how do you know it needs that as a remedy?

It did exhibit a little bit of dieseling after I turned it off the other day, this was after about 25 minutes of spirited driving. 

I noticed the ZStore also sells heat shields (pic) and I'm curious if those are helpful. Also, what's the purpose of an insulation block between the carb and engine?

[jfa.series1]

The insulation blocks on the carbs and mechanical fuel pumps help prevent direct heat transfer from the head. The heat shield does a similar thing - a barrier between the exhaust and the carbs. If your car is relatively unmolested, you probably have a heat shield already in place.

BTW - if you ever decide to tart up your ride a bit, I have a replated fuel rail looking for a good flat tops project!

 

Edited May 11, 2020 by jfa.series1

[motorman7]

This company will actually rebuild your flat tops.  They do pretty nice work.

http://paltech1.com/pricing/

http://paltech1.com/

[Dadsun]

23 hours ago, jfa.series1 said:

The insulation blocks on the carbs and mechanical fuel pumps help prevent direct heat transfer from the head. The heat shield does a similar thing - a barrier between the exhaust and the carbs. If your car is relatively unmolested, you probably have a heat shield already in place.

BTW - if you ever decide to tart up your ride a bit, I have a replated fuel rail looking for a good flat tops project!

 

That's beautiful, JFA. If you've seen the earlier pics from under my hood, you know it needs some prettying up. I may take you up on that at some point this summer. 

No heat shield currently. See pic.

[w3wilkes]

18 hours ago, Dadsun said:

From this picture it looks like you already have headers and the air ports have bolts in them? If I remember correctly back in the mid 70's MSA had headers with the ports in addition to "comp" headers without the ports with a warning that they may not be legal in your state. If those are headers, are they 6 to 1 or 3 to 2 with a "Y" connector and do you have 2.5" exhaust?

As for heat shield it looks like ZCarDepot has them;

https://zcardepot.com/products/carburetor-manifold-heat-shield-stainless-240z

 

[Dadsun]

The headers appear to be 3 to 2. And then the two remaining send through the muffler and then two stacked tailpipes.