Spread Bore Manifold Issue

[BeerDontCount]

So I was on my way to changing out my Holley 1460 carb with a 770 Avenger on my 351c 4v, and all was going well until I popped the old carb off and realized I have a spread bore manifold. Long term I was going to change the manifold anyway, but right now I don't have a garage and don't want to take that job on weather permitting. So I'm looking for a short term solution as right now to get the new carb on, and also some long term advice.

The EGR plate was milled down to what I would guess an adapter plate might look like (hopefully the attachment links at the bottom are working and you can see the pics), and then there are two thick square bore gaskets on top of the plate, raising the carb approx. 1 inch off the manifold. I am guessing that replacing the thin gasket below the EGR plate and getting two new spare bore gaskets to replicate the current carb height might be the temporary way to go to get the new carb on. Please provide feedback on this either yea or nay.

Also, looking down the road when I replace the manifold. What do I do with the spread bore EGR plate? Is the EGR plate needed? Are there square bore EGR plates available? Aside from intake manifold selection, which is another topic, what other pitfalls or considerations are there in changing from an old spread bore to square bore.

Thanks in advance for the help. Really appreciate it.

Scott

 

[Don C]

This issue comes up every once in a while. Here's one thread:

http://www.7173mustangs.com/thread-need-adapter-for-d1ze-9425-bb-intake-for-edlebrock-carb

 

[BeerDontCount]

Sounds like the adapter is the best short term solution. Can I get rid of the EGR plate and valve without any issues cropping up?

Scott

 

[Don C]

The only issue will be your DMV and emission requirements. Your engine will do fine without it.

 

[BeerDontCount]

Out it comes then as there are no regulatory issues with my collector vehicle plate here.

I also realized from the pics that the open channel on the manifold is covered by the EGR plate, but will not be covered by the spread bore adapter. Looks like I might have to rethink my willingness to R&R the manifold out in the open as that is the best solution now.

I had one more question about removing the EGR. There is a tube that runs from the EGR valve to what looks like a temp sensor plugged into a mounting unit in the shape of an H that is inserted into both of the heater hoses that run into the fire wall on the passenger side. When I remove the EGR, is there a recommendation on what to do with the hose from the EGR valve? Not quite sure what the function of that system is. Would appreciate any advice on this.

Thanks again for helping me out.

Scott

 

[jbojo]

Can you post a picture of that H shaped item that you mention?

 

[BeerDontCount]

Here are a couple of pics. There are two vacuum hoses connected. One goes the EGR. The other goes to a junction that connects to the carb base in the front, and the other end goes to what I believe is a temp sensor on the passenger side of the water pump.

Thanks for your insights.

Scott

 

[Twins]

Sounds like the adapter is the best short term solution. Can I get rid of the EGR plate and valve without any issues cropping up?

Scott

Scott. As you correctly figured out changing the manifold gives you the most versatility. That being said...I still haven't done it. As you can see thst j channel on the stock manifd.means nothing fits! 73.

So what I did was take the stock spacer plate. Take the egr valve and holder off the back and plug up the openings with screws and sealant

On my car the secondaries on the 4 barrel were actually blocked by the adapter and the previous owner was just driving it like that.

So I left the bottom side of the spacer plate alone and used the stock gasket (it has the j channel etc) to seal to the manifold.

On top I used a gasket that fit the carb and traced out the openings on the top of the spacer plate. Then I used a grinder and opened up the holes for the secondaries until the butterfly s for the carb secondaries cleared them. I re shaped the gasket and buttoned it up.

If you do not have hood clearance issues I would recommend trying to re shape an insulating gasket to keep heat off the carb as opposed to a flat gasket

Or...just change the manifold

PM me and we can talk if you need any help working with what you have for now.

Sent from my SM-G900V using Tapatalk

 

[jbojo]

Here are a couple of pics. There are two vacuum hoses connected. One goes the EGR. The other goes to a junction that connects to the carb base in the front, and the other end goes to what I believe is a temp sensor on the passenger side of the water pump.

Thanks for your insights.

Scott

Looks like that a switch to port the vacuum to open the EGR. If you don't want that EGR just remove the hose and plug the vacuum line.

 

[BeerDontCount]

Thanks for all the help. Looks like my next move is to decide on a new manifold. In the meantime I just put the old carb back on so it's still drivable. Can't believe it started right back up. LOL. It actually might be running better now. The carb bolts coming off were little more than hand tight so I may have fixed a vacuum leak....

Scott