Got a 340 stock intake... would like to know more

[Cletus]

Found this intake for a fair amount of cash, figured I'll hoard some parts for the coming 318 modifications which hopefully will take place as soon as the body is fixed...

This is, as far as I understand, a stock 340 intake manifold. How old is this intake, ballpark? How can one tell?

I have no clue (because over here, I don't really have to care) about smog stuff, EGR and such - reading up on the subject on various forums mostly confuses me even more - according to some, the EGR stuff won't affect anything, others want to plug and obliterate any traces of EGR-related holes in the intakes. Where, if anywhere, would I find EGR valves/ports on this? If present, do I need to do anything about them? Please, educate me.

 

[rumblefish360]

For a performance build plug the EGR for a constant fresh air and fuel charge. The EGR gasses are harmless and will have a minor effect that you'll never ever notice.
Give the numbers on the intake and as soon as I can, I'll look them up and tell you what year 360 that is from. Or it's the last year of the 340.

 

[Cletus]

Here we go... the intake says BZG and below that, 3671918AE.

And a better pic:

 

[Photon440]

That casting number equates to 1972.

 

[rumblefish360]

Nice Photon. That is nice that there is no EGR valve on the drivers side. The floor jets can be plugged easy enough. You can make some good power with that intake.

 

[Cletus]

Thanks guys! So it is a 340 intake then, not 360?
Also, any advice on best way to plug those floor jets?

 

[rumblefish360]

Being that I have not had that exact intake though looking at the picture on my phone says to me they can be screwed out. Take a ratchet to them and then instal a hex plug in its place.

 

[Meep-Meep]

Yep, that's the early floor jet EGR intake. Do as Rumble said - remove the jets and plug them. You don't want ANY exhaust gas in the intake stream because it will be seen as a vacuum leak (too much that is).

You may find the threads are a parallel thread (not a taper pipe) so you may have to drill larger and chase them with a pipe tap or remove the plugs and weld them closed, or plug the plugs with a pipe plug. I remember plugging those at some point but don't remember the exact details. And yes, that intake will do very well on the street with a mild cam.

 

[UKPlymouth]

Guys, by coincidence I have just been working with my own 340 manifold (3677878Z) and it too has the same EGR jet plugs. I pulled one out to take a look but can see no facility for a jet as such. It just looks like a big plug.how do they work?

For our Swedish friend, if you want to fit a Holley to that manifold you will need an adaptor as there will be a differnt stud pattern If an Edelbrock, a quarter inch spacer or the throttle butterfly's cannot fully open.

 

[rumblefish360]

The exhaust use to heat the manifold is the source. Normally one of the center exhaust ports has a passage way that leads up into the intake to heat it up so the choke works. Chrysler just tapped the floor for the jet passage ways to suck in the exhaust gas.

UK, do both of those floor jets screw out?

 

[UKPlymouth]

Hi Rumble, I only removed one, but both do come out.The one I removed seemed to be a bung in that there were no holes in it like I imagine a Jet would have.

 

[Cletus]

Thanks for the carb tips, UKPlymouth. Haven't decided which way to go yet - I believe I'll experiment a bit with my Holley 2-barrel on the stock intake before moving up to this intake and a 4-barrel.

 

[UKPlymouth]

Hey, Cletus. I pulled those two EGR plugs from my manifold and they are sealed up with carbon so I'm leaving them well alone. By the way, they are a very big ugly looking thread size and not sure what type.

 

[rumblefish360]

The thread is a 3/4 pipe thread IIRC from my '79 intake.

 

[UKPlymouth]

I fitted a brand new 670 Street Avenger to mine with the adaptor to day. Night and day change from the Edelbrock that was on it. Much more power when the secondaries come in. Really pleased with how my 340 pulls, felt lame before under throttle, but not now!

 

[Cletus]

Sweet. Looking forward to bolting this on my 318, together with a blueprinted 340 cam from Crane I scored the other day

 

[Eric Griffith]

Sweet. Looking forward to bolting this on my 318, together with a blueprinted 340 cam from Crane I scored the other day

 

[Eric Griffith]

I Just bought an entire engine assembly with that manifold.
It had a production date of 5 9 73.
Had dots between the numbers
I also found some Tubes in the intake,not sure what that was all about...but it could have been someones Theory.

 

[62 Dart Convertible]

Cletus, that manifold was designed for a Carter Thermoquad to bolt straight on, which is another carb option for a street car.