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73-87 Chevy _ GMC Trucks => Projects Posts (NOT VEHICLES) => Topic started by: JoeR on March 18, 2018, 06:58:09 pm

Title: What is this part????!!!!?
Post by: JoeR on March 18, 2018, 06:58:09 pm

So, I have a 1984 GMC High Classic that I am slowly working on.  Had the weak 305 taken out and a 350 put in.  Now I am replacing the carb with an Edlebrock 1406.  When I went to install, this part is keeping it from fitting.  It wasn't hooked up to anything so I don't think it is too important.  I am not sure though if I remove this completely what damage will it do?  If I can remove it, does anyone sell a plate to put in its place?  I admit, this is my first vehicle that I've worked on.  Not a trained mechanic by no means but this is something to keep me busy...  Any help anyone can provide would be greatly appreciated.

Thanks!
Joe

Title: Re: What is this part????!!!!?
Post by: Captain Swampy on March 18, 2018, 07:19:01 pm

That's the EGR valve. You could block it off. Are you in an area that does emission testing?

Title: Re: What is this part????!!!!?
Post by: JoeR on March 18, 2018, 07:33:59 pm

Thanks Captain!  yea, I'm in Portland Oregon.  It passed last year without this hooked up, so I'm not sure if blocking it off will hurt or not.

Title: Re: What is this part????!!!!?
Post by: Rapid Roy on March 18, 2018, 09:40:50 pm

Welcome

Title: Re: What is this part????!!!!?
Post by: Captain Swampy on March 19, 2018, 03:22:39 pm

Blocking it off shouldn't change anything if it's unhooked already.

Title: Re: What is this part????!!!!?
Post by: hatzie on March 23, 2018, 07:11:53 am

Not real keen on the China-made Edelbrock carbs.  They're manufactured to meet a price point rather than a quality engineering level.
The Edelbrock 1406 is a 600CFM unit.  The Rochester M4ME Quads are 750 CFM units with 1-3/32" primaries...  Rochester made 800CFM units with 1-7/32" primaries for Cadillac.
The Edelbrock is a very raw design that uses mechanical secondaries that open regardless of demand so it can easily run overly rich when you step on it.  An overly rich mix can wash the lube off the cylinder walls causing accelerated wear.  The Rochester is a bit more refined in that it has vacuum secondaries that only open when the engine needs more fuel and will actually burn it.
The Rochester M4ME & M4MC also compensate for altitude with a mixture compensation aneroid and a fairly refined metering assembly.  The Eddy has to be tuned for your operational conditions and, just like the universal Holley carbs, they aren't very forgiving of altitude changes.

IMHO A properly re-built Rochester Quadrajet M4ME will run trouble-free for a lot longer than China-made Edelbrock and the Rochester will perform very very well.  The Rochester also uses less fuel when you're just cruising and still has decent power on-tap without wasting fuel when you step on it.

http://www.generationhighoutput.com/Quadrajet_Service_1981.pdf