[mgarblik]

What are people typically doing, if anything, to block off this dumb passage drilled in these aluminum heads? Looking for some tested ideas. Hate that that exhaust bowl has a 1/2" hole drilled right into it.

[PAUL K]

We always block them at the manifold flange with a pipe plug.

[Schurkey]

Pound a 1/2" core plug into it? Good luck getting the hot-air or divorced choke to work properly afterwards. An electric choke can likely be adjusted to work.

How bad can a 1/2" hole be, compared to the giant open window of the OEM heads?

[steve25]

Respond 904 from Coltronics.

Fill her up!!!

I pack the crossover with aluminum foil and shape it until I only need a 1/4” layer of resbond 904.

[mgarblik]

Thanks. Pipe plug was my first thought. A little hesitant to fill it with anything on basically a street car where I won't be checking on it regularly. It's a 2x4 intake with no choke anyway, so no carb heat. Wish it wasn't pre-drilled. But it will be OK.

[NeighborsComplaint]

There are 2 choices: 1) heat w. hot air choke or or 2) no heat and electric choke. Block the passage and convert to electric choke.

[77 TRASHCAN]

1/2 inch freeze plug should be easy to obtain. You already probably have 2 of them, just a matter of where???

[Tom Vaught]

A friend of mine did a mod on a "alternative engine" that had the drilled passage from the
intake flange to the exhaust port. Obviously one on each head.

He had access to a machine shop and a lathe.
He measured the drilled hole in the head for the heat passage, created an aluminum "rod" plug that was the full length of the passage, tapped the head for an aluminum threaded plug on the intake side, welded the threaded plug to the "rod" plug, and
blended the "rod" end so that it matched the contour of the exhaust port bowl.

Now mind you the guy is a perfectionist and the heads were off the car BUT it allowed heat or no heat and the heads were
sealed very well when the threaded plug/rod was installed. Except for the "tapping operation" for the plug, the heads were like NEW.

Tom V.

[mgarblik]

Originally Posted by Tom Vaught

A friend of mine did a mod on a "alternative engine" that had the drilled passage from the
intake flange to the exhaust port. Obviously one on each head.

He had access to a machine shop and a lathe.
He measured the drilled hole in the head for the heat passage, created an aluminum "rod" plug that was the full length of the passage, tapped the head for an aluminum threaded plug on the intake side, welded the threaded plug to the "rod" plug, and
blended the "rod" end so that it matched the contour of the exhaust port bowl.

Now mind you the guy is a perfectionist and the heads were off the car BUT it allowed heat or no heat and the heads were
sealed very well when the threaded plug/rod was installed. Except for the "tapping operation" for the plug, the heads were like NEW.

Tom V.

That is a great way to deal with situation. I really like that. Could blend the rod end right into the bowl once installed. I think I am going to do this. I may make 10-12 of them and sell them to members with similar unhappiness with the E head passage. I wish the drilled passage would have been an option.

[Dick Boneske]

Are the E-Head center exhaust ports siamesed like normal cast iron heads, or are they separated like SD heads? How about KRE?

[mgarblik]

Decided next week to try and make some long aluminum port plugs for the heat passage. Going to make them 1 piece from aluminum rod. I will machine all but about 1/2" slightly smaller than the hole in the head and then put a male 1/4" pipe thread on one end. It will be long enough to protrude into the bowl a little for hand blending with a carbide burr and a sand roll. I will cut a wide screwdriver slot in the threaded end for installation. If it works and is fairly easy to make, I will see if there is enough interest to make a little run of them. Thanks for the ideas.

[lust4speed]

Originally Posted by Dick Boneske

Are the E-Head center exhaust ports siamesed like normal cast iron heads, or are they separated like SD heads? How about KRE?

It is a simple 1/2" hole drilled into only one passage on the Edelbrocks. Really pretty unobtrusive compared to the gaping chamber infringing on the two ports on iron heads.

Even in Southern California filling in the crossover passage is a two edged sword. Great in the middle of summer when temps are warm, but it takes the carb a long time to stabilize on cold winter mornings when leaving for a show. What would take a minute or two to heat the carb and intake now takes 15. Car still starts excellent, but the electric choke is programed to pull off in about three minutes, and with the intake still dead cold there is a limbo period from choke pulling off until carb actually is warm enough to fully respond.

That little 1/2" passage didn't seem like too bad of compromise. Edelbrock puts it in the 87 heads but no passage in the 72's.

[mgarblik]

Originally Posted by lust4speed

It is a simple 1/2" hole drilled into only one passage on the Edelbrocks. Really pretty unobtrusive compared to the gaping chamber infringing on the two ports on iron heads.

Even in Southern California filling in the crossover passage is a two edged sword. Great in the middle of summer when temps are warm, but it takes the carb a long time to stabilize on cold winter mornings when leaving for a show. What would take a minute or two to heat the carb and intake now takes 15. Car still starts excellent, but the electric choke is programed to pull off in about three minutes, and with the intake still dead cold there is a limbo period from choke pulling off until carb actually is warm enough to fully respond.

That little 1/2" passage didn't seem like too bad of compromise. Edelbrock puts it in the 87 heads but no passage in the 72's.

Not to be a jerk .......but since I am making plugs, the passage is actually a little smaller than 1/2". 27/64 hole. No idea how they came up with that size. Agree it's not a big deal but it annoys me and compromises the exhaust balance in one cylinder on each side. I don't need it with a 2X4 intake and no chokes anyway. A good idea for a typical street driven engine used in cold or moderate climates. Really not complaining, just don't want it for my application.

[Tom Vaught]

Originally Posted by mgarblik

Not to be a jerk .......but since I am making plugs, the passage is actually a little smaller than 1/2". 27/64 hole. No idea how they came up with that size. Agree it's not a big deal but it annoys me and compromises the exhaust balance in one cylinder on each side. I don't need it with a 2X4 intake and no chokes anyway. A good idea for a typical street driven engine used in cold or moderate climates. Really not complaining, just don't want it for my application.

I have one set of 87cc E-Heads in my inventory, Mike.
When you get the first pieces made, put my name on one piece, as
it would be nice to have that intake piece on the shelf. And a Drill & Tap size I would need for the head.

Tom V.

[mgarblik]

I am going to try a 1/4" NPT thread in the head. 7/16" tap drill. So really a direct tap in aluminum with a 27/64" hole already in there.

[MidnightAuto]

To answer the question about KRE D ports - they have no crossover at all.

[Nobuddy]

You are making them, but it it was me, I would look at 1/2-13 straight threads instead of the 1/4" NPT. I think would be a lot easier to screw in to the desired position and just loctite in place. Also easier to turn than the taper.

[mgarblik]

Originally Posted by Nobuddy

You are making them, but it it was me, I would look at 1/2-13 straight threads instead of the 1/4" NPT. I think would be a lot easier to screw in to the desired position and just loctite in place. Also easier to turn than the taper.

I agree with this. I was going to have to buy a pipe die set to do it my way. Save a couple bucks and easier to install/remove as you said.

[mgarblik]

I have these heat crossover plugs made. Crude but effective. Here are some pics and a drawing for anyone who wants to make their own. Direct tap 1/2-13 threads into the head passage. 1/2" deep.

[PAUL K]

Originally Posted by mgarblik

I have these heat crossover plugs made. Crude but effective. Here are some pics and a drawing for anyone who wants to make their own. Direct tap 1/2-13 threads into the head passage. 1/2" deep.

Nice!