After experiencing many problems with the fuel injection set up on my 2.8 I have manage to purchase a good 3.4 from a Firebird, no easy feat here in the UK as they aint that common. I have decided I am going for a rebuild aswell as carbing it over the summer then swap the engine out over the winter.
Reading numerous threads I can see for the most part what I need, the intake manifold, adaptor and 390 cfm 4 barrel carb I can get off the shelf from summit (easy option as they ship to the UK at a reasonable cost) although I may be able to get a used carb here in the UK from ebay as they do come up quite regularly.
I can either swap the current V6 fuel pump to the I4 version or purchase the Mallory pressure regulator, again I think summit sell these.
My main concern is the ignition system, what distributor should I be on the look out for. I could go used from ebay.com if the seller is willing to post to the UK or the expense of new again from summit. I have read about vacuum advance, mechanical advance, contact breaker points, electronic modules, coils and aftermarket electronic ignition sytem but not sure which way to go. I dont want to purchase the wrong distributor as there would be very little chance of me reselling here. I understand early 80's S10 2.8 are the most likely doner.
Any info on the distributor would be appreciated.
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06:07 AM
PFF
System Bot
lateFormula Member
Posts: 1048 From: Detroit Rock City Registered: Jul 2002
I recently parted out my 2.8 carb'd setup. The 3.4 is pretty much the same. If you look up threads by Oreif, he had a really nice carb'd 3.4 setup dyno'd out at, if I recall correctly, 234 hp.
To answer your question on the dizzy, you are looking for an early 80's S10/Blazer distributor with the vacuum advance module on it.
If you can find one, get an Offenhauser intake manifold. They are dual plane, and lower profile than the Edelbrock.
If you use an Edelbrock, you'll need a scoop for clearance purposes.
While you are at it, have a look at the 500cfm Holley 2300. You don't have to play around with the secondaries with that and they flow really well.
You can get a rebuild from National Carburetor cheaper than the 4 barrel, and the center hung float does not react to hard right corners like the side hung float.
Good luck with the build
Arn
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[This message has been edited by Arns85GT (edited 06-05-2013).]
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08:07 AM
woodyhere Member
Posts: 399 From: prior lake, MN USA Registered: Aug 2011
One thing easily overlooked when changing to a carb and using an off the shelf manifold is the angle of the carb flange surface. Aftermarket manifolds are made for front wheel drive cars. Motors in front wheel cars are angled back and sit lower in the back than front. Fieros motors (any swap or stock) sit dead level. It is easy to make a wedge to correct this "out of level" carb mount. It may not seem like much but the carb flange on an Edelbrock manifold is about 3/16s higher on the bell housing side on a 4 bbl flange. Float level changes of 1/16th make a big difference on A/F ratios. If you need some help on making a wedge for making the carb sit level, send me a PM and I'll be glad to help. The aforementioned distributor is a good choice.
------------------ woodys 427
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09:38 AM
stewnew Member
Posts: 118 From: United Kingdom Registered: Oct 2006
Checking the link to Rock Auto brings me to Fiero distributors, I assume these are for the standard electronic ignition used in the Fiero rather than the basic vacuum advance one I am looking for from the early 80's 2.8 engines.
Is the S10/Blazer distributor a straightforward contact breaker points unit with condensor, that just requires a coil and a vacuum connection for advance/retarding. If so is it wise to change this to an aftermarket electronic module and coil set up. I read in one post about using a Crane Fireball unit.
It's not just Edelbrock manifolds that have the flange made for rear wheel drive, it's any brand made for rear wheel drive. To ignore good advice because you didn't notice any ill affects isn't very scientific. Any carb is designed to sit level. The wider the carb the more the out of level effects performance. I would suggest that you have no basis for your opinion. You haven't corrected your flange tilt to see if there is a difference. I have. Holley 4bbls aren't as sensitive as the Edelbrock 4 bbls but still need to be level. The small Holley 4 bbl is a better choice than the 2 bbl. Small primarys make for great throttle response and good mileage. Secondary opening rates are easy to set with such a small 4 bbl carb. A non-computer controlled dist will be realible, simple and run like a thief in the night.
I have noticed a difference. If a car was constantly climbing a hill you can bet there would be a problem. Why not do the right thing and have this fellow mill the flange flat before it goes on the engine. It is simple to do. If the engine is together, make a wedge. I don't like 390 either. I'm not wild about Holleys in general but have used them a lot in the last 40 years. Whenyou need a 1050 no one else makes one. I like the (AFB) Edelbrock, especially the redisgned new series. I can easily get a 16 or 17 to 1 F/A for cruise and, depending on the motors likes, a 12.5 for performance. The holley is much better at accepting a slant due to it's narrow fuel bowls. The Edelbrock and other similar layout fuel bowls really hunt around on the A/F meter. If you have one handy take a look at the fuel bowl. The floor slants up to the secondary jets. It was made that way to have an even fuel level and not flood on excelleration. My 800 Edelbrock avs varied several ratios when it sat at an angle. Leveling it made a surprising change. The F/A ratio now only varies by tenths. It would stumble on hard lefthand corners and doesn't do that anymore It's not like it costs a bunch or is difficult to do.
------------------ woodys 427
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06:26 PM
Jun 6th, 2013
stewnew Member
Posts: 118 From: United Kingdom Registered: Oct 2006
I am going to try and keep it simple as that was the purpose of moving away from the FI system.
Based on the recommendations
I will start my search for the offenhauser intake (is there a part number) as this sounds like its going to be tough to track down. Where should I be looking, please bear in mind I am in the UK, not everyone is willing to ship overseas. I can try the Mall here, ebay.com, plus I read about people using craigslist although I have no experience of this as it does not exist here. If no luck the edelbrock one is off the shelf but this may cause clearance issues.
A choice of a 500 cfm 2 barrel or 390 cfm 4 barrel (vacuum secondaries). The manufacturer appears to be important as the design of each has potential flaws with float and bowl positions.
The use of wedged spacer to ensure the carb is level if max carb performance is critical, will work without.
The Mallory pressure reducing regulator.
An early 80's S10/Blazer distributor, found one on ebay.com in Florida but its in poor condition and missing parts, no others listed from my search criteria.
A suitable ignition coil, either a replacement or OEM performance unit.
I am looking at a camshaft and roller tip rockers upgrade but will not cover that in this post as I just want to get these fuel and ignition items correct.
Its going to cost me a fair sum and I only want to do it once, so its got to be right. A measurable improvement in performance along with increased simplicity is key, fuel consumption is not. This will not be my daily drive as with most American cars owned in the UK, with fuel at the equivalent of around US$8 per gallon taking in exchange rate and litres to gallon conversion a mortgage is required to run one on a daily basis.
Although you still need that same distributor... have you considered going with an aftermarket fuel injection system? They have self-tuning systems from Holley and others. You sort of get the benefit of a carburetor, but also the benefit of fuel injection, spark, and timing advance (you replace the points in the distributor).
The Rockauto site looks good, its clever enough to pick up my UK IP address and price everything in sterling. Are they competitive for most items, gaskets, filters. Do they sell perfomance items such as camshafts rockers etc?
I will commence my purchases in the next month or so once I have got my workspace sorted and start tearing down the 3.4. I need to check the condition of the all the internals and compile a parts list.
Just found a distributor from an ebay.com seller ,US$85 plus shipping to the UK is reasonable. The advert says GM Century/Celebrity 173 V6 80 to 88. A quick read of various web pages leads to think this may do the job as these "A bodied" cars had the 2.8 60 deg V6 carb'd engine fitted.
Any comments to confirm this would be greatly appreciated.
Check the Rockauto part number for the 84 blazer dizzy and then check the Century part number. They should have picks for both. If the Century is correct, it will have the vacuum actuated plunger on it.
Hope this helps
Arn
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04:01 PM
FFIEROFRED Member
Posts: 751 From: GULFPORT, MS Registered: May 2008
A fuel pump for a 1972 vega will be a elec pump for a carb. the 2.5 tbi 84 fiero pump is set for 15 pound. the vega pump is set for 3 to 5. I have one on my 350ci chevy DUELLY. It is a little shorter than the fiero elec pump. a longer hose will fix it.