DGV or Holley 4B conversion

[Blue Meanie]

Looking for opinions here. Thinking about doing a carb conversion on my 72. I know the purists want me to stick with the sidedrafts, and that is still a possibility. But I would like to get your opinion as to these conversion.

Thanks for any and all info!

[Arne]

I guess my first question would be, "Why?" What are you hoping to gain? What other mods have you done to the engine?

[Blue Meanie]

Stayed pretty stock. Upgraded plugs, wires, points, rotor, distrib, dist cap, wiring harnesses, new alternator. I'd like to get a little more reliable performance out of the fuel system. The SU's and I don't seem to be getting along.

[Arne]

In that case I'd say that a conversion will be a lot of expense and headache for no gain. Not that there is anything wrong with the conversions, but both the Holley and the DGVs are far more complex than the SUs. Both will take some fiddling to get them dialed in on a stock L24. Of the two, the DGVs are probably going to be closer out of the box, but they still require syncing, which is one of the things that some people don't like about the SUs.

In my experience, the biggest problems with dual SUs is that people can't leave them alone. They are always the first thing that people start tinkering with if something doesn't seem right with how the engine is running. But 95% of the time, the carbs are not the problem. Once SUs have been properly set up, they don't change on their own, so they should not be re-adjusted unless something else that affects the engine's breathing (cam, header, displacement) has been changed.

[ncz]

Eric, have a friend who has the 4 barrel. Ran rich forever, until he got a smaller Holley than the one that came with the kit. Could never jet it correctly and the outlying cylinders seemed to run lean. I have the DGV's and they ran great when the car ran last, but the guy who installed them took the time to rejet. Whenever I get the old girl back together, I'm going with Z-Therapy SU's. Have the cores to send them in my cabinet. I think I tried to give an opinion in there somewhere??? Good luck, your motor looks great. I think the SU's polished with the euro balance tube and some cool air filters would make the motor look even better and run great. Maybe a mild cam also!!

[Blue Meanie]

I'd really like to find someone around Indianapolis who'd at least look at my SU's and tune them professionally. I guess that would make me feel better. Thanks for the advice guys. That's a quick $900 I don't need to spend. !

Oh, and thanks for the engine compliment! Spent a lot of time on that.

[Arne]

I'd really like to find someone around Indianapolis who'd at least look at my SU's and tune them professionally. I guess that would make me feel better.

They're not hard to tune yourself, just takes time and a bit of knowledge. The knowledge can be acquired by purchasing ZTherapy's video.

[Blue Meanie]

Thanks again Arne. I'll do that.

OT what size 14" are you running on your Z? I just finished cleaning up an old set of 14 x 7 aluminium slots and need to get some new shoes if you will. If I recall, aren't you an ole' tire guy? I was thinking about Sumitomo 195/60R14's all around.

[Arne]

Thanks again Arne. I'll do that.

OT what size 14" are you running on your Z? I just finished cleaning up an old set of 14 x 7 aluminium slots and need to get some new shoes if you will. If I recall, aren't you an ole' tire guy? I was thinking about Sumitomo 195/60R14's all around.

Way too short, and a bit narrow, assuming your wheels are truly 7" wide. I have 206/60-14 on mine, and hate them, as they are still too short as well. I'd recommend 215/60-14 to even get close to stock height.

But then again, some people like really short tires. I'm just not one of them. I want the tire to look proportionate in the wheel opening.

[Blue Meanie]

I don't really care for short myself. Thanks man! I actually asked about 215/60 R14's and the local guy at Tire Barn said "ah, no".

[Arne]

Be careful with the 215/60-14s though. Depending on the offset of your wheels and whether the car has been lowered (or even just 'settled' over the years) you could have clearance issues in the front while turning. I'd recommend test fitting one on the front before you go for this size.

While they don't look as wide, I plan to go with 195/70-14 on mine. Those are the same height as the original 175-14 (and came stock on the 280Z), and shouldn't cause clearance issues on any normal wheels.

[Bruce Palmer]

Back on the SU situation for a second. The biggest problem with tuning old SUs today generally has to do with the fact that most of them at this point in their life are worn out. Speaking for the ZTherapy built carbs (which is all I know or care about) once the 3 or 4 systems have been returned to square one (as new) they are a piece of cake to keep up with. I tweak mine once in the spring when the weather changes and once in the fall when the weather changes, add a little damper oil every once in awhile and that's it.

Worn out SUs don't tune for sour owl feathers even if a guy knows how to tune SUs. Our video and DVD is a heck of a coaching tool for dialing in your own.....