The Stovebolt Site Forums The Shop Area Engine Shop Question of pricing for rebuilt 261

Guys,
I'm almost complete with the rebuild of my 261 Jobmaster. (3733813 Block, 3836850 head).
I'm still undecided if I should install it in my '59 half-ton though, as I'd also be happy with a more original 235 and I even have parts to begin building that one.
If it would buy me a great complete 235 I might sell the 261 and reinvest. Thoughts?
Anyway, I was just wondering if I WERE to sell the rebuilt and painted Jobmaster complete, what could I possibly get for it?

Jerry

Its worth about twenty bucks... checks in the mail, send it to me once rebuilt asap!

As you probably know the 261 engine is a popular size in demand. I would add up all your cost for machining and replacement parts,and some for your own labor. 261s can run from a $500 or lessfor a reduildable core to a multi thousand dollar complete rebuild and/or modification. If you really want a 235, I would post an ad in Stovebolt and see if someone has a comparable even trade value wise with a little cash thrown in with the 235.

I'd put that into the '59 and not think twice about it! Paint it Blue if it makes you feel better. Why wouldn't you want the 261 in your truck? About one in a few hundred people at the truck show will ever know that you don't have a 235 anyway. Impress yourself, not the judges.
I'd be willing to bet that, along with better power and torque, you'll also get better fuel mileage from the 261, because it won't be working as hard. Paint it Detroit Diesel Aspen Green or 261 yellow, and people will literally be drooling over your truck. Go on and treat yourself, you earned it!

I lucked out when I thought I purchased a 235 and found out it was a 261. It was just over $2000 for a complete rebuild, the block was 100 with all the fixin's on it. If you want to get 2 Gs for it, be prepared to stand behind it for a year.

Thanks for all the input guys... even you, Big Tee! Ha!
I actually have less than $500 in it so far, which includes block acid bath and check and having it bored out. New valve guides, pistons, rings, cam bearings freeze plugs and main bearings and Detroit Deisel Alpine Green paint (I've already painted the valve cover, oil pan and side cover).
All I need is rod bearings and gaskets. I'll paint the head, block and bell housing then assemble the engine
The only thing I'm bothered about is my cam is a 235... Does it detract from the 261 value? Or is it just another "who really cares"?
Anyway, I saw a rebuilt 261 on Ebay for over 2G and my jaw dropped. Maybe I DID just get lucky. I was thinking if my engine was worth anything near that, it would pay for my truck, all my new tools AND a rebuildable 235 + some change.

Jerry

I'd say the cam is important, depending on what year 235 cam you are using.

http://chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0142.htm

Hopefully, someone will correct/clarify this: there are different "235 cams" in different years. It looks like all 235/261 truck cams from 54-57 were the same.

The 261 truck cam was used in the 53-55 Corvette 235 (it was/is a higher lift cam). And, presumably the 261 cam could be used in other 54-57 235 blocks? I'll be putting one that I bought (from a Corvette 235 engine builder) into a 1954 235.

However, there are other 53-57 car 235 cams that are different (and might not provide the higher-lift of a 261 cam).

1958-1963 235 and 261 cams may or may not have been the same - does anyone have a Master Parts Book that goes beyond 1957 (I have one at home and will check it out tonight or tomorrow).

There are 2 different 261 "corvette" cams.
During the 1954 corvette production the camshaft was changed, increasing the horsepower to 155.

The later design camshaft can be identified by three dots between #5 and #6 inlet cam lobes.

Tom,

Would you think there would be a noticeable improvement in performance by using a 261 cam shaft in a 1954 235 truck engine? Did GM change to the higher-lift cam in mid-54 Corvettes for more horsepower and/or for more torque and or for "sales appeal"?

Was the same camshaft used in later 235/261 truck engines (as shown for replacement cams in the MPB)?

A well designed cam will make a huge difference. when I rebuilt the 235 in my 54 many years ago, I had the ignorance of youth on my side. I decided that I was going to buy all of the speed parts that I could find new. Iskenderian made 2 streetable cams for the 54 235. What they call the 3/4, and the "full race". They were both the same price. The spped shop that ordered it for may advised me to go with the full race as in his opinion, "buying the 3/4 was paying good money for an essentially stock cam". It is quite a thumper with a surprising amount of pull. It is a little lumpy in the idle department and will not be installed in the 261 when the time comes as that lumpy idle works against the hydra-matic shifting in my opinion. The irony is that the full race 235 cam specs are the exact same as the 3/4 cam listed for a GMC.

Point is, I think there is much that can be gained in a cam. But the name of the game is not just throwing more lift and duration. It is a balance between the two to offset design flaws in head design and valve limitations.

Put in the 261!!!

If you want to look original, paint it the standard Grey. No one will know any different!

Or go green like me..............

The 1962 261 (page 128 of the pdf) seems to have come with the same cam as in the 1954 261 (page 115 of the pdf).These same references also seem to show that 1962 truck 235 had the same cam is in the 1954 truck 235, milder in both duration and lift than for the 261. However, as Tim pointed out, the Master Parts catalog shows the 1956-57 trucks use the same cam for the 235 and 261 engines; the GM data packs also do indicate this for the 1956, 57 and 58 trucks. However, in 1959 the 235 engines went back to the milder cam. Maybe if someone examined all of the torque vs RPM curves this might be obvious, unless the performance curves came from the marketing department instead of a dynomometer.

If one does believe the performance curves, a comparison of the 235 and 261 data in the 1955.1 data book (pages 92-99 of the pdf) does seem to show that there is a benefit at higher (>2500 rpm) engine speeds for the 261 cam (and a larger carburetor?). For example, at 2000 rpm the 261 puts out 10% more HP than the 235, just about what the change in displacement and compression ratio would predict. However, at 4000 rpm, the 261 generates 21% more HP than does the 235, indicating at least another 10% for the cam and carb. The benefit may be less on a 235, as the airflow demand and pressure drop will be lower. If I can find my engine simulator program, I might try to see how much of the extra 10% is due to the carburetor with the larger venturi diameter (1-15/32" for the 261, 1-11/32" for the 235).

The 1954 Corvette data pack indicates (page 2 of the pdf), as Tom pointed out, that the cam was changed during the 1954 run to increase HP from 150 to 155. However, the GM data packs for the 1953 Corvette (page 6 of the pdf)and the 1955 Corvette (page 10 of the pdf) show the cams for both years to have the same timing and lift. The 1954 book did not contain any cam data that I could find. Another surprise was in comparing the cam timing for the Corvette and the 261; same duration and lift, but the cam in the Corvette seems to be advanced eight degrees.

Has anyone ever had a chance to check the profiles of any or all of these cams?

Hoyt