My hubby and I just bought a 1981 with a 350 (after selling our 95 and 87 :sad: .) It is in desparate need of a carburetor and numerous other things. We are thinking of converting to fuel injection.
Has anyone else done that? Do you recommend it? If not, what's a good carb?

 

Zwede used the Holley fuel injection kit on his big block. He has a website about the setup and such. I really want to make this conversion as well eventually (fuel injection, not necessarily the holley setup) I'd probably go the TPI route myself.

 

You'll find quite a few folks here with fuel injected C3's. You will also find that there are as many opinions on which carb to get as there are carburetors :lol: . If you using the stock motor, I would recommend a stock replacement, since yours is computer controlled.

AC

 

Thanks, I'll take a look!

 

can also get an efi shop to convert a manifold for use with EFI.
like a victor junior.
this is what ill do when i do the conversion on mine.
Im going to go the whole way and do a sequential fire TPI with the ignition controlled by the computer aswell.
but this will be in a while when i have money :D

 

There is an article in Hemmings Rods and Performance that trys to answer the question of weather EFI makes more power than a carburetor. EFI is a dry flow system. The carburetor is a wet flow system because fuel and air run through the whole intake manifold. The computer controlof the EFI allows for better mileage and emmissions. The carbutetor enjoys the benefit of cooler charge air temperatures from the latent heat of vaporization, which consumes heat from the intake manifold during the gasolines phase change. For every ten degrees F the charge temperature is altered, power is impacted by one percent. Also stock EFI manifolds are not designed for high RPM power. If you have a stock engine and money is no object then fuel injection would be nice. If you are building the engine for power and or you don't have a lot of extra money I would go with a Carburetor.

 

Go with your heart :lol: There are many pros and cons. If you go with a stock conversion, it goes great, but if you modify it can be a PITA. I'm enjoying mine today, but tomorrow could be a whole new day.

 

You also need to consider whether or not this mod will be emission legal in your state (Washington?)

Fuel injection would be a nice mod, but I wouldn't do it just for the sake of replacing a sick carburetor.


[Modified by Neo Fender, 12:00 PM 9/28/2001]

 

Fuel Injection. If you've got the patience.

Vic

 

There is no question, EFI has more potential for power. Carburetor runner design is limited because of the need for (a) plenum(s). With EFI, the runners can be shaped any way your hearts desire, just look at how different TPI runners are from carb'd intake manifolds. If you want, you can retrofit injectors on an old style intake as well.

Also, the amount of control you have over the air/fuel ratio is much greater than that with a carb. I remember Monty mentioned when he was tuning his motor he adjusted his A/F ratio by something like .1 and picked up 20-40 ft/lbs (I forget exactly how much). At any rate, with a carb you don't have a lot of granularity to your adjustability.

With EFI you can also tie in electronic ignition controls, which could take the place of centrifugal and vacuum advance to have non-linear advance curves, and highly tuned advance scenarios.

The only problem with EFI is that a system that can handle real power is going to start at over $2000, and that is a low end one without many options. Also, a full out drag car which runs at only high rpms may not see any or little gain, because there is no need for low RPM drivability, and therefore no compromise.

EFI offers other benefits over carbs like smoothing out the torque curve (a carb that works well at low rpms will not work as well at high rpms and vice versa; it's always a compromise), cold engine drivability & warm up, gas mileage, longer plug life, better emissions, and a lighter wallet ;)

Carbs on the other hand are very easy to tune, very reliable, very easy to troubleshoot, replace, rebuild and otherwise work on. They are also cheap. I got my first Holley at a swap meet for $40, $20 (rebuild kit) later and some elbow grease - as good as new.

As far as a good carb, a lot of guys on the forums are happy with their stock Q-jets, or a Lars (tm) rebuilt Q-jet. You might also consider a Road Demon (625 cfm, good size for the street), they come with an electronic choke, holley compatible parts and they look very nice and are affordable ($300?).

Rob



[Modified by robzr, 8:13 PM 9/28/2001]