The Stovebolt Site Forums The Shop Area Engine Shop BEST HEAD FOR 261

I HAVE JUST COMPLETED THE REBUILD ON MY 261 FOR MY 61 1/2 TON APACHE AND NEED YOUR OPINON AND JUSTIFICATION FOR WHICH HEAD YOU THINK WOULD BE BEST TO PUT BACK ON IT. I HAVE THREE CHOICES FOR YOU TO CONSIDER,THE ORIGINAL HEAD WITH CASTING NUMBER 3836850,A 61 HEAD FROM A 235 WITH CASTING NUMBER 3836848 OR ANOTHER 235 HEAD THAT I BELEAVE CAME FROM A MID 50'S VETT WITH CASTING NUMBER 3701887.ALL THREE ARE SITTING IN MY SHOP AND HAVE BEEN TOTALLY RESTORED AND ARE JUST BEGGING TO BE CROWNED THE WINNER OF THIS DEBATE!!!!THE LOCAL STOVEBOLTERS HERE ALL INSIST I PUT THE ORIGINAL BACK ON IT,BUT I WANT YOUR OPINON FIRST.
I HAVE READ ALL THE THREADS RELATED TO THIS SUBJECT AND STILL CANT DECIDE WHAT TO DO.
THANKS

I will soon be building a 261 and have been planning to use an 848 head. I've also read the posts and it seems quite clear that this is the head to go with for highest compression. Maybe there are other considerations, if so let's hear em!

Just make sure the extra steam holes are drilled in the head before putting it on the 261.

I am building a 261 ci as we speak.I'm going with the 848 head from a 1956 235 car engine.I am not sure,but believe there are six steam holes that need drilled.I would have to go out in the garrage and look to be positive.

My oldest brother asked me a good question the other day. He asked me if different thicknesses of head gaskets were used to change the compression ? I did not have an answer, logic would say a thinner one would bump the compression up. Is this something that was done in the past and currently is still being done ? I told him that i would ask my fellow bolters, somebody will have the answer.

Thanks,Tim

The 3701887 head is from a '53 235. I'd say the 848 head would be better.

I am also building a 261.
It was rebuilt in the early 80's and came with an 848 head (highest compression).

To my surprise, the steam holes had NOT been drilled, although a 261 gasket was used and there are holes in the gasket.

Gents,

As a newbie I am curious if anybody knows what sort of compression levels can be expected with the 235 head on a 261 block?

Thanks,


Stewart

Since swapping the 235 for a 261 it would seem your goal is more power/performance. That is why I am going with a 261 and all discussions I have heard here and from industry performance experts is that the 848 provides the most power/performance due to slightly higher compression. I have not even thought about any other head for the 848 seems to be the obvious best choice.

Your question didn't state for what purpose this 261 is being used. I'd say if you are building a stocker the 261 head would be just fine and for normal driving there probably would not be a dimes worth of differance. Now if you want to really improve performance increased compression would be just the first step. The easy route as stated would be the 848, Inliners have been touting this trick for years.

My goal is to enhance the performance somewhat.I am not trying to build a high pro engine,but if I can get just a little more torque/horsepower,I'll go for it!!
Looks like the 848 is the winner and I am now convinced to go that route.I will just oil the original head down and store it so I will always be able to put her back original with the correct parts.
I am a little stickler about that last point,IE;keeping all original parts,no matter the condition.One can never tell when you might need to referance something from the original part and it is comforting to know that I never did away with any part of an otherwise original truck.
Thanks for all the responce and help.Hobert

Yes! That's the way to go... I'm keeping the babbitt 235, oiled-up and wrapped-up in plastic.

Standard 261 head 7,17:1
With 235(...848) head (milled .030 of an inch) you rise the compression to a sensational 7,9:1

So you see it`s not a big deal at all but may add arround 8-10 horses and also saved some gas (about 5-6 miles per gallon)

Frank

The 848 head on a 235 from the factory was 8.25:1 compression. I would suspect that if you had a .060 over bored 261 with flat tops you would crank at least 160psi = 9.0:1 minimum. Still pump regular gas.

Yeah, I reviewd my numbers, 52pu is right.

Now I go and pour some ash on my head (not the cylinder head)

Frank

The 848 head has the smallest cumbuston chamber and will raise the compression on the motor about .5:1. A '58 to '62 261 has a compression ratio of 8:1 by installing the 848 head you will achieve a ratio of approx. 8.5:1 (assuming the head has not been milled and stock pistons).

Thanks Rougie for your input.I was thinking about all of this and was wondering what might happen if you put a 261 head on a 235 motor since the head would have the steam holes and the 235 block would'nt or does it even matter?
I dont have any plans to do that but I would like to know if anyone has and how it worked out.
Hobert