Edelbrock 340 heads with factory HP exhaust manifolds

[340challconvert]

A66 and 34O Challenger owners- Using Edelbrock 340 heads with factory HP exhaust manifolds
Writing to help others who may have an issue with factory exhaust manifolds and using Edelbrock aluminum heads;
Installed an NOS exhaust heat shield on the driver's side head studs, then installed the factory hp 1970 exhaust manifold. Finally started the newly rebuilt 340 and had a bad exhaust leak! Manifold is intact, in good condition with mating clean surface. Using new eddie aluminum heads specific for the hp340.
It  looked like the exhaust manifold wasn't squeezing the bottom side of the gasket for some reason.
Thank you to MK for his thoughts. Based on his suggestion, I took a look at the bottom of the exhaust manifold to look for problems with the bottom of the factory 340 gasket. After some further research (abodies) had a lot of information on small blocks with this issue; Edelbrock heads designed for the 340 have a larger flange on the bottom right side that does not allow the easy use of the factory hp left side manifold. It protrudes far out enough to interfere with the seating of the exhaust manifold. In fact edelbrock recommends the use of headers with their 60179 340 designed heads. (Now I find out)
I should have done additional research when I purchased the heads. There is a solution though; to use  a header flange and gasket on the one side with some very prudent filing of either the head flange or the exhaust manifold. Have to be careful if filing the new head due to the closeness of the water passageway in this part of the head.
(One last gripe; why would edelbrock design a head specific for the 340 and not allow the use of the factory manifold on one side?)

[mk]

Glad you figured it out !

[MoparLeo]

I think that Edelbock assumes that their typical aluminum cylinder head customer is looking for a bump in performance and no factory exhaust manifold will help when choking an aftermarket heads flow.
They are quieter but will not fool anyone that your engine is stock.

[340Challman]

Sorry. Have to dig up this old thread.

I knew about this issue and thought I had it resolved until yesterday. I had a spacer cut to match the exhaust manifold so that it would not impede flow. I used 3/16 thick steel. It provided the necessary clearance. Yesterday I ran into problem number two. The head pipe hits the torsion bar. I am using Accurate exhaust, so according to all the feedback I have read, these are the best fitting pipes out there. Yes, I understand that they were designed to fit on a factory engine with factory heads. Edelbrock makes no mention anywhere that these heads WILL NOT work with factory manifolds. I removed the gaskets on this side and am using high temp RTV, so there is only the 3/16 extra for the spacer. It did not improve the spacing at all. It is still solidly up against the torsion bar. How much clearance is there between the head pipe and torsion bar using factory heads? Do the Edelbrock heads have the mating surface for the exhaust that much different than factory heads? Is the angle of that mating surface different? All of this information should be spelled out by Edelbrock so that the consumer can be aware of issues that they are going to run into. @MoparLeo Even if I was using headers, they would be designed to fit based on the factory mating surface location and angle, not the multitude of aftermarket head manufacturers. One would think that these aftermarket manufacturers would design their heads within those known parameters, unless they are going to be very transparent that they would be racing heads only. @340challconvert  How did you deal with this issue? It sure can't stay this way.

[Chryco Psycho]

I am not a fan of the EDDy products , too much core shift & soft alum alloy .
 Not sure if the Trick Flow 190 heads will work better with manifolds .

[Brads70]

Not that you should have to but would a shim in the motor mount help with clearance between the exhaust pipe and the torsion bar?

[340Challman]

I am not a fan of the EDDy products , too much core shift & soft alum alloy .
 Not sure if the Trick Flow 190 heads will work better with manifolds .

I agree completely CP. I had purchased these heads 4 years ago and the issues I have ran into with these and other products from them have cured me for good. I. will not spend any more money with Edelbrock.

With that said, unfortunately I have far too much money tied up in this engine with custom pistons, head work, tuned and dynoed to be thinking about swapping. I am a couple of weeks away from turning the key on this thing and I can't accept the thought of pulling the motor. Right now I'm thinking my only options are to take this head pipe in to a local shop and see if there is any way they could put a slight bend in it. Which I doubt due to the proximity to the flange. Or have them make a whole new head pipe to mate up with the rest of the Accurate Exhaust. Never a dull moment. It seems the closer I get to turning the key the more B.S. problems I run into. 

[340Challman]

Not that you should have to but would a shim in the motor mount help with clearance between the exhaust pipe and the torsion bar?

I'm not quite sure how I could shim it, but even if I could, I have zero hood clearance now. If I go up any at all I risk hitting the hood. I actually thought about whether they were too tall, but when I looked at the steering link, I realized that they can't be too high. If I came down there, I'd run into issues. Damned if you do, damned if you don't. 

[MoparLeo]

My post had nothing to do with anything other than appearance and flow.
I would loosen up the motor mounts and trans mount and reset the engine in the mounts. You don't need much and there is play with the centering of the engine in the cradle.

[340Challman]

My post had nothing to do with anything other than appearance and flow.
I would loosen up the motor mounts and trans mount and reset the engine in the mounts. You don't need much and there is play with the centering of the engine in the cradle.

Now that's an idea. I will have to look at that. Thanks for that. 

[Brads70]

Not that you should have to but would a shim in the motor mount help with clearance between the exhaust pipe and the torsion bar?

I'm not quite sure how I could shim it, but even if I could, I have zero hood clearance now. If I go up any at all I risk hitting the hood. I actually thought about whether they were too tall, but when I looked at the steering link, I realized that they can't be too high. If I came down there, I'd run into issues. Damned if you do, damned if you don't. 

I had to make a .090" shim on the passenger side to tilt the engine away from the torsion bar. Not difficult to do or make . It's basically a square piece with a slot that slides between the motor mount.I have a BB but same principle.... Or you could dimple the exhaust tubing to gain the required clearance. Not that you should have to but we have to deal with what we have sometimes. 

[HP2]

Yes, sometimes a slight shift in engine location can help with where things fall in relationship to interference. Loosen up all those bolts, lift the passenger side slightly, maybe bounce it a couple of times, check clearance, and tighten down the driver's side and work your way around to the rest of the fasteners.

Also along that line of thinking, if the shifting the engine does not yield the clearance you want, I have another idea.  Remove that exhaust  pipe, then use a sawzall or cut off wheel, make a cut just under the flange, halfway through the pipe, on the engine side. Don't go all the way through. Keep this gap around .125 but no more than .200. Then push this gap closed and weld a bead over the cut. This will change the angle on the pipe just a minor amount at the joint, but at the torsion bar level, will have moved it over .5-.625 of an inch over. It also puts the weld bead under the flange where it is not noticeable.

[Katfish]

Yes, sometimes a slight shift in engine location can help with where things fall in relationship to interference. Loosen up all those bolts, lift the passenger side slightly, maybe bounce it a couple of times, check clearance, and tighten down the driver's side and work your way around to the rest of the fasteners.

Also along that line of thinking, if the shifting the engine does not yield the clearance you want, I have another idea.  Remove that exhaust  pipe, then use a sawzall or cut off wheel, make a cut just under the flange, halfway through the pipe, on the engine side. Don't go all the way through. Keep this gap around .125 but no more than .200. Then push this gap closed and weld a bead over the cut. This will change the angle on the pipe just a minor amount at the joint, but at the torsion bar level, will have moved it over .5-.625 of an inch over. It also puts the weld bead under the flange where it is not noticeable.

Smart idea!
But if it was me, I'd just use a BFH and ding it.

[340Challman]

Smart idea!
But if it was me, I'd just use a BFH and ding it.

 

I sent my BFH to BFE because I used it too much. 

[340Challman]

Also along that line of thinking, if the shifting the engine does not yield the clearance you want, I have another idea.  Remove that exhaust  pipe, then use a sawzall or cut off wheel, make a cut just under the flange, halfway through the pipe, on the engine side. Don't go all the way through. Keep this gap around .125 but no more than .200. Then push this gap closed and weld a bead over the cut. This will change the angle on the pipe just a minor amount at the joint, but at the torsion bar level, will have moved it over .5-.625 of an inch over. It also puts the weld bead under the flange where it is not noticeable.

Another outstanding idea. This problem is in the bag. Too many good ideas here. Many thanks guys.