I just got my 848 head back from the machine shop. I thought I would share the progress. Anyone else thinking about this sort of project might find this info interesting
This head was a gift from Leo (1953 Panel). It was presented as a decent, clean used head. I forget now if he said the engine was running prior to disassembly (Leo can fill in the blanks). Anyway, upon inspection, the head turned out to be crack free and ready for the upgrades necessary to use it with my 261 engine (Also a gift -- from Scott 48bigtrucks Ward). This head has been through the full spa treatment -- steam holes drilled (to mate to the 261's water jacket), new valves, guides and seats, spring seals and it has been decked/resurfaced. For those contemplating how much, total bill from the machine shop was $625. I have no idea if that is good, bad or average. Not possible to have the work done locally, so this was done as a package deal with another 'Bolter in the Philly Area ... (Guess who?? ) who has access to a known good machine shop. I have some clean up to do before it can go on (plus, we have a whole bunch of work to do with the block yet, anyway.
The 3rd image shows two of the steam holes.
In the last picture, you will see proof that not all 261 blocks have the "Captain's Bars" This block is a 1st year (1954) and does not have that casting mark. Also, the early 261's will accept the 216 water pump in the correct position that doesn't require the adapter mounting plate.
V/R John
~ John
A kid raised on Hotwheels, Matchbox and Tonka cannot be reasonably expected to own only one vehicle as an adult.
1949 Chevrolet 3804 In the Legacy Gallery | In the Gallery Forum 1973 IH 1310 Dump 1963 Kaiser M38A1 2001 International/AmTran RE3000 "Skoolie" 2014 Ford E-350 4x4 (Quigley)
That looks like an excellent job of head reconditioning, and while the price seems a bit steep to me, you've gotta remember I grew up around a shop where the lowest labor rate I can remember was $5.00 an hour! Of course, at that time the minimum wage was 90 cents an hour!
One little tidbit of trivia for folks intending to rebuild a stovebolt head- - - - - -the exhaust valves in an 848 head are identical to the ones used on small block V8's, and even the stainless steel ones are dirt cheap on Ebay. If you want to do a little pocket porting, a set of 1.6" diameter small block V8 exhaust valves aren't hard to adapt to the stovebolt head. I've got a later model 261 with an 848 head on it stashed away in the "one of these days" project category that's earmarked for the "Cadillac 292" upgrade with a stroker crankshaft, and I'm planning to do the big exhaust valve modification on it.
I'm really glad I chose to invest in machine tools over the years that make it possible for me to do most of my own engine machining! 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!
The rebuilder of my original 1954 pickup's 235 engine put in those SS V8 valves, at my request. The rebuilder had done this before and made sure all clearances were/are correct. The engine started up quickly and was easy to tune (original/rebuilt Rochester BC carburetor). I do not know when I'll get to drive that truck - motivation, and space are lacking, and finding a finish-painter is holding me up (all sheet metal is straightened and epoxy primed).
I did not go with a 261 on this truck, because I wanted the Hydra-Matic engine/transmission to be numbers-matching. So, I compromised by settling with the 848 head's casting codes and a 261 camshaft (which was also used in many 235 Corvettes).
Be sure to check your intake valve/piston interference, especially if you decked your block. I have an 848 head and someone before me milled off an unknown amount (perhaps .030-.040, just looking at it), and with the Langdon Bulldog camshaft installed my intake valve to piston clearance (measured with checking springs) was only .070 with a blue Felpro head gasket. And my block was surfaced, but not decked.
~ Dave 1950 Chevrolet 3600 3/4-ton with 261 engine & T5 Transmission
We used to consider .060" to be a minimum clearance between pistons, valves, and other potential points of contact on engines that could wind tight enough to float the valves. The chances of that happening on a stovebolt are somewhere between slim and none, so your engine should be good to go. "Milling", "surfacing" and "decking" are synonyms for the same process- - - -removing a thin layer of block or head surface to assure a good gasket contact, or cuttng considerably more for adjusting the deck clearance of pistons or increasing compression. Making radical changes in the block or head surface dimensions can affect valve system geometry so it's a good idea to do a test assembly and make sure other adjustments like adding shims between the rocker stands and the head won't be necessary. 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!
I had to replace the 848 head on my 261 last December. After 10 yrs of trying to keep up with traffic on I-10 (65-70mph) the valve seats were hammered into the head. Lucky me I had another stashed under the bench. Machine shop that I have used for 30+ yrs., replaced all the seats, guides, seals, and surfaced the head $450.00 out the door. I am happily driving the truck again, but with the addition of World Class Borg/Warner T5 transmission, The I-10 speeds are now at 2,000 rpm.
) who has access to a known good machine shop. I have some clean up to do before it can go on (plus, we have a whole bunch of work to do with the block yet, anyway.