The Stovebolt Site Forums The Shop Area Engine Shop which head for a 261 rebuild?

I'm rebuilding a '62 261 to swap for the original 216 in my 1950 3100. I have two NOS heads: one is the stock 3836850 used on all 1954-62 261's. The other is a higher compression 3836848 'vette.

I think the '848, with steam holes drilled into the water jacket passages, will be the best choice. My application will be mostly travel at highway speeds (I'm also changing the ring and pinion, and swapping the 3-speed for a Saginaw 4-speed), with some light towing. Is there any reason I should reconsider my choice of cylinder head?

TIA for your advice. Mark

The popular opinion is that the 848 head is better: more compression and flows better. The actual boost may be more in your morale than in performance. Either way will be a noticeable improvement over your 216. What ratio R/P? 3:55 is rather popular. Sounds like a nice enhancement to your truck. Be careful or you'll get used to the passing lane.

I think that the "848" head is a 235 head not used only on the corvette. From what others have said the 848 is a good choice to use on your 261 as long as you drill the steam holes.

The "248" head (3836848) was first used in 1956 and it seems it was the replacement 235 head from 56-62.

It makes me cringe (I'll get over it) when people refer to "steam holes" in a block or head - if the water/coolant is boiling, someone has a big problem.

I think an article by Jim Carter started people using the term "steam holes". GM referred to the holes between the three pairs of "siamesed" 261 cylinders as six extra "water passages" or "water holes".

Tim

the 848 head will change compression by itself from the stock 6.2 to depending what you read 7.8 to 8.1. there are a bunch of 261 rebuild threads in the engine shop. just search them out (261 as key word). i know because you have the same build going on as i do, right down to the year of the motor. and i have started a few of the threads good luck

Mark:

I am also in the midst of the same rebuild using the 848 head. One word of caution: When I disassembled my 261, I found that someone had used a 235 head gasket which, of course does not have the holes in it for the extra water holes. Make sure you have the right head gasket.

Has anyone ever measured the combustion chamber volume of the 848 and 850 heads with consistent equipment and technique? I have heard of and seen conflicting information. Mark: If you have access to a decent burette it would be great to get some good data for the cc's in each head, especially if they have not been milled. I have an 848 head and an 850, but the 850 is bolted to the engine right now, and it will be a few months before I will be able to pull the 850.

Hoyt

The 848 Head.....

Passenger 1953 Full pressure

Trucks 1955.2

Oilrag,

Yes, the "848" will work on the '53 engines. That MPB is the 57 edition and by that year the "848" head was the replacement head provided for all 18 bolt 235 heads.

Here's the 1953 replacement head in 1954. The "848" head was supposedly not available until 1956.

Tim