The Stovebolt Site Forums The Shop Area Engine Shop Drilling holes for "848" head when installing on 261 engine

This had been asked in earlier threads but no "answer" was found on my search.

Have 1956 truck 261 and a 848 head off a 235 engine. I need to drill the holes in the head to match the holes in between the sets of cylinders on the 261.

Is the bit used the same size as he holes in the block?
I also remember a question being ask about "angle", so is there and angle??

I figure everyone uses the gasket as the template?

Any information is appreciated. Deve?? Wayne??

Extra question: I have a dual offenhouser intake and fenton headers. This is a new rebuilt engine, not by me. I pulled the head off to "verify" everything and to get it unstuck. So far all is going well.
I'm thinking about using a single 235 intake to get the engine running and tuned in. It is bored, with new valves/springs ect and has a "racing" cam in it but I do not know the lift or brand.
Until I get healed up from surgery my nephew is helping me.

1. drilling holes in the head?
2. start it up using the single intake?
3. use standard setting for adjusting valves as starting point? (new lifters)

There's a tech tip somewhere that gets referenced pretty much every time this question comes up. I suppose somebody will post a link to it soon. Basically, use the 261 head gasket as a template and mark the steam hole positions with a transfer punch, then drill the holes at a slight angle with the bit pointed toward the center of the head. I think it's about a 10-15 degree slant. This helps the hole intersect the entire coolant passage above the head deck instead of just getting a partial flow.

The reason for the holes is the same one that requires steam holes in a small block 400 V8 head- - - - -no openings between the siamesed cylinders for coolant to flow. Without the holes in the head and the gasket, steam pockets can develop where the cylinders meet at the center of the block.
Jerry

This is from Inliners. Pics at the bottom of link.

http://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=51987

If you want Chipmunk, just send the engine and head up to me and save yourself the trouble.....LOL

John

Nice link to the pictures posted on the inliner group, Jerry.

John

I was thinking CurtB posted a detailed "How To" over on inliners. Good post Drew, maybe someone here can make it a Sticky before it gets lost!

We just talked about that in the thread named 848 head. Tim provided a picture. Hope this helps.

Thanks for the responses guys. I had followed the 848 head post earlier but didn't think a couple questions I was wondering about got answered.
...you got to remember, I was in the middle of having eye implants when I had heart surgery so I'm still half blind until July 31. Bear with me guys...Bear with me!

Heart surgery and eye implants,and still working on your "Bolt"! Yo "Da Man",Chipmunk!! Jerry is right-on with his advice. I have the "stock" head,(steam ports,stock cam),on my 261. When I add/change coolant,I need to "burp" the system,to get rid of the air pockets. The first time I added coolant,I wasn't aware of that fact,and lost almost 2 gallons of antifreeze,when I,(luckily),over-heated in front of a mechanic friend's house. He started it up,and at high idle,added water,until the engine finally got down to operating range,(about dead center). It took about 10 minutes,but it seemed like a lot longer,hearing that thermostat bang open and shut,from the difference in water temp. I drove it back to the farm,and the gauge dropped down to 1/4,on straight water,on a 95 degree day!! Now I know!! I have Fentons on my 261,but I use the stock intake. I'm not sure,but I'd think you'd be better off trying to set your vacuum/timing with the dual carb set-up,especially since you have a cam. Otherwise,you'll be doing it twice. I may be wrong,but with a "racing" cam,the single carb. will act a lot different than a dual set-up would?? Hope this helps! B.T.W... GET WELL SOON!!

Thanks wetwilly. Here's where I'm at right now..... I have the head at my pals machine shop but he won't get the holes drilled till Monday.
Since I don't know exactly what cam the PO put in it I'm thinking go ahead with the Fentons but I have a nice 235 intake I blasted and cleaned up some time ago. I'm thinking to start it up with the single carb manifold and if it runs good I may just leave it and not mess with the dual intake offy. Besides, I don't have two carbs right now but thanks to a great Stovebolter I'll have one in a couple days.

Since its at my nephews house, so I can't work on it, he has a nice vacuum system that you pull a vac on the entire water system, then it will pump the antifreeze and it'll fill it up. No air pockets...hopefully anyway. He's a mechanic and has all the good gadgets and gizmo's. I'll be watching!

Hey, wetwilly, I may regret it later but I can't just sit and do nothing. I spent quite a bit of time in the shop today restoring a 1919 and 1927 Utah tag. I'm practicing to do the '37 tag for my pickup! Nothing heavy, heck, I can't even raise the garage door so I got my granddaughter to do it.

I'll keep everyone posted on how the hole drilling comes out. 3/16th bit. 12degree angle and a new gasket for the template....holes bored toward the manifolds.More later.