Technical we need a dedicated 261 thread.

Alright, I know this is probably a dumb question, but why does everyone want the 848 head on the 235, and not just deck the stock 261 head to bump the compression? If you say decked the 261 head or the 235 head?

 

Umilled 848 head combustion chamber is 79-80 cc's,261 head (850?) is around 88 cc's.Bolt an umilled 848 head on a 261,you get about 8.2 compression in place of the 261 head 7.4 compression.Milling a 235 848 head gets you more compression if that's the way you want to go.
As of yesterday my 261 looks like this.I welded a nail to the timing cover for a pointer and marked the damper when I had the degree wheel out to check cam timing.The tubular pushrods are 30 buck Sealed Power items,plenty sturdy and lighter than stock ones.I ordered a bunch of shit from Summit like oil filter adapter and hoses,a SBC do it yourself header kit that'll give me all sorts of bends to build a header.Got the header flanges on Ebay.And of course high ZDDP break in oil.
I paint the engine when it's fully assembled,gives the factory look

 

Where did you buy the pushrods??

Does anyone now where can i buy performance valvesprings?

 

Many years ago, I searched the size listings of valve springs in an old TRW catalog and found that springs intended for 455 Buicks make a good high tension replacement for 235s.

 

Do you really need high performance valve springs? These engines don't really rev all that high.

 

Interesting, thank you for the info!

Yes! I'm going to use a hotter camshaft and and want to be able to rev pretty high!

 

My engine shown above has Buick 455 valve springs with aftermarket retainers. The stock retainers don't fit the Buick springs properly.
No,they don't rev all that high..About 4200 the way this one is tuned.But with a "3/4" cam the little extra pressure of the Buick spring is good insurance.And they cost only a few bucks more than stock 235-261 springs.
The pushrods came from Rock Auto.you can find them on Ebay or at your local parts store.There are several different lengths,so know what you need.

 

More stuff getting done.The 50 Chevy PU is in the garage now ready for the engine swap.
The 261 needed some sort of header so I built one.Nicely done 3/8 thick header flanges on Ebay for 45 bucks,a handful of assorted pipes,Porta-Band,grinder and the MIG. No nuclear grade welds here so a little grinder work I suppose.I get a bit crude at times ,LOL.1-5/8 primary tubes,2 inch secondary into a single 2-1/2 outlet.A 2-1/2 inch elbow band clamps on the outlet .I'll make up the rest of the exhaust once the engine is in the truck.Not a tuned header but it'll do the job.



The draft tube is cut and turned 180 degress facing up.A breather goes on the end.The small tube on the rear of the valve cover get a PCV valve. Do this on all my old 6's

 

In it goes

 

Nice job Tony.

 

Thanks Cosmo,should be running in a few weeks.Have you done anything with your 261?

 

Well, here she is, '54 261 bored out to 280 with a Corvette exhaust manifold hanging on there. The period Edelbrock intake doesn't match up as it's a 216 platform, so I'll probably just go with the Fenton set-up I have on the '56 235.




Notice the machined bar steel stiffeners for the valve train assembly, this necessitated a riser to use the alu.Wayne cover.





I need to button up this good looking all-synchro '69 3sp+od, I looked into modding a 4 speed to get the 8 speed but there is too much crossover and not enough advantage to go through the hassle.





I've been wanting to go with that '69 od for a couple years but the damn '62 non-synchro that I rebuilt 11 years ago that I bought from Jack Halton just works perfectly so I'm just going down the road in no hurry. I guess that's why I don't have the 'pedal to the metal' on this quite extreme (for me) changeover.

Hey Tony what rear end/tranny are you going with? For me living in the foothills hard by the blue ridge mountains the '57 3.90 rear I have with the .70 od for the great high way is ideal. It will be exciting to test out the whole new set-up going over the Afton pass at speed !!! VRRROOOOOMMMM!!!!

 

Cos,my 50 truck will keep the original SM420 4 speed and the 3.42 8.5 10 bolt rear I swapped in last year.My engine is more built for midrange power than blasting by flathead Ford 8's . And I like the vintage sound and feel of the truck transmission.60-65 mph with stock brakes and suspension is good enough for me.
I built a Saginaw 4 speed with O/D and had it in the 302 GMC powered 37 Chevy truck for several years.The 4 speed and 3 speed mainshaft are the same making it an easy swap into a 4 speed if you have the O/D parts.Really doesn't give 8 forward usable gears due to gear ratio overlap.I always kept the O/D locked out unless I was in the fast lane,didn't like the free wheeling thing.I first used a 3.11 gear set,too low for my tastes even with a 3.36 rear gear.A 2.85 first gear set worked out better with the 302 engine in a 2900 pound truck.Original Saginaw O/D most likely has a 2.85 first gear .

 

I finished the swap today.Primed the oil system again and looked for fuel.There used to be fuel.AD trucks have a fuel tank higher than the fuel pump,and a shut off valve at the tank.I shut off the valve,turned it back on,feels fucked up.Got to siphon out a 1/4 tank ,fix the problem.
This was a few hours before finishing

 

Anybody ever put a mcculloch blower on one of these motors?

 

I'm looking into buying a 261 out of a 62 truck. It runs but the owner says it will smoke if left idleing. With a tight budget in mind what could I do with engine to make it a reliable cruiser.
I've been told rings, head job, cylinders honed, and new rod bearings. - that's sounds expensive...
Any tips on how to get this 261 on the road??

 

First off, print off the list of block casting numbers and make sure it's really a 261; if the truck is smaller than 1 1/2 ton, it didn't originally come with one. Since I can't see inside the engine from here, it's anyone's guess how far you'll have to go to eliminate the smoking.

 

smoking engine and tight budget don't go together. Look for something else unless you can aford at least $1500 for a proper rebuild.

I did hone/ring jobs on stuff when I was yonger just to get buy, and they never really work out in the end. It may not smoke as much, but it will still use oil.

 

Just joining up, I have a 261 i pieces waiting for my 235 to die someday.

 

Hey City Boy, I found out you put sawdust in the oil of the 261 you sold me. never smoked a bit - just like you said!!

 

No sawdust.....just four quarts of SAE 50 and two cans of STP.

 

Alright guys, thanks for the info. I was hoping with more time then money I'd be able to get this 261 to stop smoking. What better an engine than the chevy straight-6 to be one of the less attention needy(money)?

 

I'm new to 261's, what can you tell me about this 261 here.

 

Well, from the pictures, all I can really say is that, because of the full flow oil filter, it is in all likelyhood a 261.

 

I,m just going to pick up a complete drop in 261 and use it in our 52 plymouth cost 150.00

 

What's the hose connected to passenger side of the engine for? It's laying right on the valve cover, that just doesn't seem correct?

 

It's got a PCV valve integrated into what is usually a road draft tube. It was optional equipment on trucks back then.

 

The pcv was optional?

 

Hey All,

I have a 1963 chevy K-10 with a 261 6 in her. There seems to be some confusion on that option but mine is a 261 and I am pretty sure it is original. My question is , does anyone have any info on the suffix codes for this engine. My id reads F0712LB, witch means I think Flint, the 7th of December and I guess LB is a 261, but does that LB also tell me the year. I guess 1963 was a year of change for these trucks but the 4x4 carried over much from 1962. My engine casting #3769717 tells me it is a 1962 261. Does this mean they put a 1962 engine in the 1963 4x4 trucks? Any discussion would be apprieciated.

Mike

 

they continued to use the 261 in 4x4 trucks into 1963. How far into '63, I can't say. The casting date code for the block is above the starter...