276 stroker from 35 years of parts

[GB SISSON]

WELL...... It appears I got lucky. I cleaned up one of the other EABs enough to test, but found they looked about the same area inside of a test gasket and had a serious rust pit in a bad place. I then went for the pair of nice red merc EAC (I had thought they were 8CM) heads. Buffed one of em out with the cup brush. I could see from the headgasket 'template' that this one had more like a 3/16" flat inside the head gasket. Encouraging, evidence of milling, but less so. And voila! I think the pics tell the story. And now I get the added bonus of 'Mercury' logo. I found that at the crown had a measurement of .042. I only did cyls 5 and 8 again. I will clean up the other head before lunch and start a test on the valves. I am hoping for good numbers there as my cam is mild. Geekers. I think I 'done good' this morning.

[petehoovie]

Originally Posted by GB SISSON

WELL...... It appears I got lucky. I cleaned up one of the other EABs enough to test, but found they looked about the same area inside of a test gasket and had a serious rust pit in a bad olace. I then went for the pair of nice red merc EAC (I had thought they were 8CM) heads. Buffed one of em out with the cup brush. I could see from the headgasket 'template' that this one had more like a 3/16" flat inside the head gasket. Encouraging, evidence of milling, but less so. And voila! I think the pics tell the story. And now I get the added bonus of 'Mercury' logo. I found that at the crown had a measurement of .042. I only did cyls 5 and 8 again. I will clean up the other head before lunch and start a test on the valves. I am hoping for good numbers there as my cam is mild. Geekers. I think I 'done good' this morning.

[Bored&Stroked]

Great News! Is it good that you have a bunch of parts to choose from and that you're taking the time to get this all figured out. You definitely don't want .025 over the crown as once that fills up with carbon, then you get some "knocking" from the carbon whacking the head! LOL

[cadillac512]

GB, the EAC heads look like they'll fix the problem (never would have expected that problem!). The EAC's do have a bit less compression but you'll be just fine...you're not building a racer. Good job with the checking.


p.s. The MERC script alone is worth an easy 10 HP.

[GB SISSON]

Thanks for the kind words all! I've managed to stretch this into a 5 day weekend now, and counting. I did find some tight quench areas on the merc heads, but a couple spots at .030 and some at .035 got me to doing some grinding. Once started, I decided to take everything to .040 or a bit over as a few areas were more like 50. When I was in an area that showed .038, I blended it into an area of .042. I wanted to err on the high side of .040, not the low side. I find a dremel or die grinder is rather hard to contol so I used a worn down 4" grinding disc and traced the outline inside a standard size head gasket with a sharpie. I took out the sharpie line and a little over in the low spots for the overbore. I musta smashed a hundred foil balls today, and lifted those darn heads at least 40 times on and off. Consensus here says it will be worth the effort.
Since I hate sitting around doing nothing, I reassembled and primed my truck pan and made some main cap hard washers that fit in the milled areas on the caps. The grade 8 washers at our hardware store are too large ID. Plenty of room on front cap so I made six. Stacked them on a long 1/2" bolt and angled them against my beltsander spinning and scuffing. While much of my shop work may be a bit too'Gilligan's Island' for a lot of folks, I'm thinking these washers with their neatly beveled edge would please even the most discerning 'barners.

[Bored&Stroked]

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Plus, because you've increased the cubic inches to 276, you'll pick compression back up due to the increased cylinder volume.

[Bored&Stroked]

You got it brother!

[flatjack9]

Those Merc heads don't look to me like they have ever been milled. Do your pistons protrude above the deck at all at the edge?

[GB SISSON]

Flatjack, not the slightest bit above the deck. I could get a close up of a piston at TDC tomorrow. Most of the heads I have came from the large stash of blocks and parts I bought from a neighbor. He inherited them from his father in law and being a diehard bowtie goon, he considered them "boat anchors". The FIL had junked 13 cracked blocks a year earlier and these 9 were his 'keepers'. I had to drive 1 1/2 miles to pick them up. Guy was obviously huge into our V8s . All the heads were bolted face to face as pairs, with a sheet of corrugated cardboard in between. I have zero details on any history.

[38 coupe]

Things are looking good. Good news on the Mercury heads working for you. That is exactly the same method I used with foil balls. Clearanceing the heads looks like what my friend did on his Mercury heads. Fun, isn't it? The hard part is not overthinking things.
Thanks for all the pictures, this will be a nice reference for other folks building engines.

[GB SISSON]

Here's a couple of photos of a piston at absolute TDC. The piston's top is chamfered and I don't have the experience to call it. Protruding or not? In the one photo you can see the damaged corner on the block.

[flatjack9]

Looks to me from the photo that the edge of the piston is protruding slightly above the deck.

[GB SISSON]

Since at this point I was really looking for it, I would agree with your observation. Good part of this is that those EAB heads could very well find a home on one of these other blocks and be in the correct range of squish.

[Tim Ayers]

Originally Posted by flatjack9

Looks to me from the photo that the edge of the piston is protruding slightly above the deck.

Jack,

I agree. I've dropped off on this thread for a bit and now I'm jumping back in.

[petehoovie]

Originally Posted by GB SISSON

Here's a couple of photos of a piston at absolute TDC. The piston's top is chamfered and I don't have the experience to call it. Protruding or not? In the one photo you can see the damaged corner on the block.

[flatjack9]

This would explain why you are getting such tight clearances. I don't know that I have ever had that happen in one of my engines. Perhaps the block has been decked?

[Tim Ayers]

Originally Posted by flatjack9

This would explain why you are getting such tight clearances. I don't know that I have ever had that happen in one of my engines. Perhaps the block has been decked?

Jack,

I was wondering the same. If you look at one of the picts, it looks like one side of the piston edge seems to be out farther than the other making me think it could have been possibly angle milled.

[Tim Ayers]

Originally Posted by flatjack9

This would explain why you are getting such tight clearances. I don't know that I have ever had that happen in one of my engines. Perhaps the block has been decked?

I was wondering the same.

[tubman]

A "Dazzle of Zebras"? Well, I'll be damned.

[tubman]

Yep, Barney Navarro was also an advocate of "pop-up" pistons in flatheads.