A Z-11 Followed me Home

[jim_ss409]

Jim409_Pontiac and I just got back from Detroit.
We picked up a set of Z-11 heads and a block assembly.
The block and heads are freshly rebuilt and everything looks good.
The block has been decked so there's no stamping but the date codes for the block and heads are all within five days of each other. It's got Eagle H beam rods and a Z-11 spec cam. It's also got the 3.65 stroke Z-11 crank.
There's no intake or valley pan and there's no Z-11 oil pan or valve covers.

The only issue I see so far is that the stock 2.10/1.72 valves have been replaced with something like 2.25/1.88 (I'll check tomorrow)
They're good Manley stainless valves and I don't mind the little bigger intake but I wish they wouldn't have gone out to 1.88 on the exhaust.
I stopped by our engine guys shop on the way home and got him to look at the heads. They have been mildly ported by somebody that knew what they were doing (maybe years ago) but the transition to the new valve job needs work, especially on the exhaust.
He put them on his bench and the intake flowed 332 @.700 343 @ .800 which is pretty good but he said they should pick up a fair bit with just smoothing the transition to the valve seat.
The exhaust were really bad, only 217 @ .700
For comparison, our aluminum Bob Walla heads flow 286 @.700 with a smaller 1.75" valve.
Again, the exhaust ports look good but there is a bad step where the valve job ends.

Of course, we have no intention of hogging these heads out to max out the flow but we will let our engine guy carefully smooth out the transition.

I'll get more pictures tomorrow but I did get this one of the head on the flow bench...

 

[Dewman]

That's a GREAT find! Congratulations!

You folks sure know how to live a blessed life!

 

[1961BelAir427]

WOW That is better than saying the Dallas Cowboys Cheerleaders followed you home. What length rods and what pistons?
I know valve placement is different with the Z11 heads enough to warrant different pistons.......maybe the exhaust will be tilted away from the bore some compared to regular 348/409?? That would be nice anyway. Was the engine ran at all in current form? And if so, did they have to notch the block to clear that big exhaust valve?
Wish I hadn't opened this tonight. Was the first post I saw after deciding I need to get some sleep. Now I probably won't get any. hahaha. Excited for ya'll.

 

[63 dream'n]

Congrats.....it's apparent how much you two enjoy this hobby......and I'm glad your choice is chevys 409.your good for its legacy

 

[BSL409]

That's a GREAT find! Congratulations!

You folks sure know how to live a blessed life!

 

[buildit]

Good that you guys have it.

 

[Don Jacks]

Fantastic!!!!!!!!!!! Congrats.Are you thinking of using them on the 55?

 

[Blk61409]

Jim, good for you for preserving another Z-11!!
I'm sure you are well versed in all the Z-11 stuff, but wanted to share one thought with you.
It is my experience that the more the heads have been "surfaced/cleaned up a little" the more problems you will have with the valley cover and intake fitting. The intakes seem to take on a life of their on with regard to "flexibility" or lack of seating properly. I would definitely set all this up in advance. I'm probably preaching to the crowd, but just thought I would share this.

 

[tripower]

Congratulation...

 

[jim_ss409]

WOW That is better than saying the Dallas Cowboys Cheerleaders followed you home. What length rods and what pistons?
I know valve placement is different with the Z11 heads enough to warrant different pistons.......maybe the exhaust will be tilted away from the bore some compared to regular 348/409?? That would be nice anyway. Was the engine ran at all in current form? And if so, did they have to notch the block to clear that big exhaust valve?
Wish I hadn't opened this tonight. Was the first post I saw after deciding I need to get some sleep. Now I probably won't get any. hahaha. Excited for ya'll.

The rods are 6.135 which I believe is the same as the Z-11's came with.
We checked the stroke and it is 3.65 like it's supposed to be.

We also did some measurements and the 1.88 exhaust valve is going to be a problem. It hit's the side of the cylinder before .250 lift.
We'd rather not notch the block but I think we might be able to go back down to a smaller exhaust valve. It looks like the throat of the exhaust port wasn't opened up when the bigger valves were installed. On the one port we checked it was about 1.56" which might allow us to use a 1.75" valve.
It looks like the exhaust valve on the Z-11 heads is in pretty much the same spot as it is on regular 409 heads but the intake is about .190 or .200 closer to the intake side.

The pistons will also need work. The valve notches are in the right place for regular 409 heads but they won't work with the Z-11 heads.
The exhaust notch is positioned OK but it's just barely big enough, the oversized valve is just touching the sides of the notch.
The intake is worse. The area highlighted with felt pen is where the valve is hitting. These pistons were obviously made to regular 409 specs.
We kind of expected this problem. We've got a mill so fixing the pistons isn't a big deal, mostly just work to pull the pistons and put them back in.



We put a truck head back to back with a Z-11 head and used a center punch through the valve guides to mark the valve centers.





In this picture you can see the dimple left in the intake valve of the Z-11 head.
The dimples are highlighted with felt pan and the center of the intake is marked.
The off center mark on the intake valve shows where the center of the intake would be on a regular head.

Jim, good for you for preserving another Z-11!!
I'm sure you are well versed in all the Z-11 stuff, but wanted to share one thought with you.
It is my experience that the more the heads have been "surfaced/cleaned up a little" the more problems you will have with the valley cover and intake fitting. The intakes seem to take on a life of their on with regard to "flexibility" or lack of seating properly. I would definitely set all this up in advance. I'm probably preaching to the crowd, but just thought I would share this.

Yeah, I've had engines that needed double gaskets to seal up the intake.
I'm pretty sure these heads have been decked a time or two and I know the block has been decked so I'm thinking silicone will be my friend when it comes time to seal up the valley pan.
I did feel in through one of the water jacket holes in the heads and the deck feels reasonably thick, about the same as the 333 head I had out. I know this can be a problem area on these heads if they were decked too much.

 

[MRHP]

Congrats guys! I hope you can't tell I am jealous as hell.

 

[1961BelAir427]

Ronnie said in the other thread that the Phantom's engine has served so well it could be put on display and retired....and I said no don't take it out of service in it's prime.....just maybe make it milder and stick in another project.

Well as much as I'd love to see a Z11 built along the lines of the discussion towards the end of the BBC vs. Z11 thread......I'd be tempted to just dress it out and put it on display. Z11's are near holy grail territory for all of us on here. I'm not jealous.....I know I'm not worthy of one. Don't have anything worth putting it in and no where worth displaying it either unless I put it in the house with us. lol

 

[63 dream'n]

.......We're not worthy......we're not worthy......

 

[MRHP]

I would build it and run the hell out of it. If you aren't going to use it, buy a picture of it, the picture is cheaper.

 

[jim_ss409]

.......We're not worthy......we're not worthy......

Ronnie said in the other thread that the Phantom's engine has served so well it could be put on display and retired....and I said no don't take it out of service in it's prime.....just maybe make it milder and stick in another project.

Well as much as I'd love to see a Z11 built along the lines of the discussion towards the end of the BBC vs. Z11 thread......I'd be tempted to just dress it out and put it on display. Z11's are near holy grail territory for all of us on here. I'm not jealous.....I know I'm not worthy of one. Don't have anything worth putting it in and no where worth displaying it either unless I put it in the house with us. lol

The engine that's in the 55 Chevy is one that Ronnie built for Barry Taylor. It's still running like a top. I always cut the oil filter open to check for any cuttings when I change oil and it always looks good.

We're not 100% sure what we're going to do with this Z11 engine.
We do have a 62 Belair Bubbletop project car that it would be really cool with this engine.
Or we could look for a 63 Impala and build a Z11 clone.

We've also got a 481 stroker in at the machine shop. I'd love to put these heads on it and use in the 55 Chevy in the meantime but if we do that, we'll go a little conservative on the cam to keep the rpm's down. I think a guy could safely make pretty good power with these heads.
The 481 is a Passenger car block we got from Quick9er. We filled it with Hardblock and got some four bolt mains for it from Bob Walla.
With some help from Ishiftem we finally got some Diamond pistons that should make lots of compression.
Here's one of Ishiftem's pistons. The ones we got for this 481 look pretty much the same.



Russ Campbell ran a 9.21 with GM Z11 heads. This was on a stock block stroked to 482 ci.
That was in the car that Dick Mackenzie now owns. That's outstanding if you ask me.

I think we could come up with a much milder combo that would still get the 55 Chevy down the track a few tenths quicker than it's running now.
I would be happy to crack into the high nines with a 50 year old engine.

At some point we will gather up the correct parts and assemble this engine as close to factory original as we can make it. This engine has a Crane Z11 spec cam in it now and that's the way it'll probably stay. We may or may not use the heads on the 55 for a bit but this block will probably just get wrapped up and put away until we get a car ready to put it in.

I got a picture of the heads sitting on the block today...




There were also some loose parts that came with the engine. One interesting thing was a GM Z11 piston.
Just for comparison I took a picture of it beside a regular GM high performance piston.
The Z11 piston is on the right.

 

[Z-11Guy]

Great find, was any of the iD # still intact that might of showed a partial VIN# of the car it went into originally on it? Thanks

 

[bluescreamer]

I believe this is the motor that Russ posted a 9:20 in NSS. You will see that the heads are not GM, but
Rich Rojeski's castings that minic Z-11 heads. They flow a lot more air than a stock Z head.

 

[jim_ss409]

Allen, I looked up the post that Russ did. The car ran even quicker with the aluminum heads,,, 9.16 but it ran 9.21 with the factory heads.

Great find, was any of the iD # still intact that might of showed a partial VIN# of the car it went into originally on it? Thanks

No, we looked pretty hard for any trace of a stamping on the block but it's been decked.
It would have been great if this block had stampings that could tie it to one of the original Z11 cars but there's also a good chance it's a replacement block.
The date code on the block is 283 and the heads are 283 and 278. I think that works out to roughly mid October and I'm guessing the year would be 1962.
(it's an 814, 1963 block)

 

[1961BelAir427]

The block and one of the heads being cast on exactly the same day seems to be a good sign that this block and heads have always been together. I don't think I've ever heard anyone say how many 427 W crate engines were built. I know there were several top end packages that sold over the counter.

 

[Blk61409]

There were exactly 50 crate engines built for the 50 production cars. I have the exact number of partials built also. Not many. Dick, Robert or Phil I'm out of town, you might have the docs handy. Either way it was not many. Can post more next week if anyone is interested.