| |
Click on image for the lowdown. 
====
| | | Forums66 Topics128,124 Posts1,056,334 Members48,439 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Feb 2007 Posts: 53 Wrench Fetcher | | Wrench Fetcher Joined: Feb 2007 Posts: 53 | can i drill out a 235 head for the three sets of steam holes that will match the steam holes that are in the engine block, I just realized while replacing my head gasket that the head I have used is a 235 without the steam holes and my engine is a 261, should I be concerned about the lack of steam holes?
thanks
jeff | | | | | Joined: Aug 2005 Posts: 1,186 Shop Shark | | Shop Shark Joined: Aug 2005 Posts: 1,186 | Yes you can but as I recall it's a tricky job. There was an article on the Stovebolt about doing this but I can't find it. Hopefully somebody else can find it.
Bruce | | | | | Joined: Dec 2005 Posts: 2,557 'Bolter | | 'Bolter Joined: Dec 2005 Posts: 2,557 | I had my machine shop drill mine using the original 261 head gasket as a template.
Tim
1951 3100 Chevrolet1951 Chevrolet Suburban CarryallImage"A house is built with boards and beams. A home is built with love and dreams." "Look deep before you leap !!!" / "Everything is Everything" "If I say a mouse can pull a house, hitch him up"
| | | | | Joined: Feb 2004 Posts: 29,809 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,809 | The holes need to be drilled at a slight angle to make sure they intersect the proper cooling passage. Straight drilling only allows about half the diameter of some of the holes to flow coolant.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Jan 2000 Posts: 591 'Bolter | | 'Bolter Joined: Jan 2000 Posts: 591 | I drilled my own using the head gasket as a template. No problems.
don | | | | | Joined: Sep 2010 Posts: 695 Shop Shark | | Shop Shark Joined: Sep 2010 Posts: 695 | Hi Jeff,
I also drilled out a 235 head using the 261 head gasket as a template.
I used a titanium bit in my hand drill and it cut through very easily.
I think the bit size was 3/16" but it's been a while. You can measure the block hole size.
As Jerry mentioned, check the passages for any angle you might have to make to intersect.
The critical point is the surface location to assure the hole opening will meet the gasket and consequently, the block holes.
Keep aware of the gasket combustion seal area. The holes are CLOSE and you DON'T want to get into that!
Some people opt to not drill and just let the head cap off the holes in the block... I think that's a mistake.
This 261 bad boy needs to be cooled by design.
Just my 2 cents...
Good luck!
Jerry W. | | | | | Joined: Mar 2005 Posts: 1,513 'Bolter | | 'Bolter Joined: Mar 2005 Posts: 1,513 |
1952 1300 Canadian 1/2 ton restomod You Tube | | |
|
|
| |
