|
|
Joined: Jan 2003
Posts: 318
Backyard Mechanic
|
OP
Backyard Mechanic
Joined: Jan 2003
Posts: 318 |
:confused:
Help me, help me!
I'm confused. I have been told all of my adult life that the high compression cylinder head used on 235 engines ending in the casting number "848" was used from 1958 to 1962. Now, some one is telling me that head was also used in 1956 and 1957.
Can someone please verify the years the "848" heads were used?
Thank you!
See Facebook Page for Joe Fuchs to see more pictures of my 1937 Chevrolet 1/2 Ton Pickup
|
|
|
|
Willwood Engineering
Wilwood Engineering designs and manufactures high-performance disc brake systems.
Wilwood Engineering, Inc. - 4700 Calle Bolero - Camarillo, CA 93012 - (805) 388-1188
|
|
|
|
|
Joined: Dec 2001
Posts: 10,379 Likes: 1
Technical Advisor ChatMaster - 10,000
|
|
Technical Advisor ChatMaster - 10,000
Joined: Dec 2001
Posts: 10,379 Likes: 1 |
Hi 6cylindersovertexas Stay with me on this one and if you follow the instructions exactly you will get your answer. Back out of this string and go down to TECH TALK. Enter Tech Talk, In the upper right you will see a pull-down menu. Pull it down. Select "Show all Topics". Press go. Now there will be many subject lines. Select "Casting Numbers". Scroll down approximately 7 pages and you will find Cylinder Heads. You will find among other things that the 848 head was for 1956. (What is a 235 High Compression Head?) 
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
|
|
|
|
|
Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
|
|
ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
The compression ratios of 235 heads were-
53-55=7.5 to 1
56-57= 8.00
58-62=8.25
The 848 heads began in 1956 and continued thru 1962 .Were also the parts replacement head going back to 1953.
The same casting was used from 1956 and up but a little more material was milled off of the surface to go up from the 8.00 ratio to the 8.25 in 1958.Your goal would be to find an 848 head with a 1958 or newer casting date.The 8.25 was the highest C.R. head used and was designed for use with regular grade fuel.
Gene Schneider
|
|
|
|
|
Joined: Dec 2001
Posts: 11,162
ChatMaster - 10,000
|
|
ChatMaster - 10,000
Joined: Dec 2001
Posts: 11,162 |
I assume that was Regular grade LEADED fuel?
I have a 848 head that is off of a 56 1/2 ton truck.
Since it is also a replacement head for a 53 would milling the 53 original head be equal to a 848 head, or is the combustion chamber smaller in the 848?
What is the compression ratio for a 1957 261 engine?
Life's a long winding trail, love Jesus and ride a good horse!
|
|
|
|
|
Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
|
|
ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
The C.R for a 1957 261 was 7.8 to 1...Raised to 8.00 to 1 in 1958 and that was its max,
The 261 was designed to run on regular fuel-would equal about 85 octane by todays rating.Leaded was never specified for any car-only minimum octane number.Lead was never required for use in an engine - only after its removal some said it was necessary to "lubricate" valve seats.This has proved to be false by most engine rebuilders today.Have run unleadded for years in my old cars-driven them at high speeds -under load-etc. with no problem.
The combustion chamber was the same from 1953 and up-the 1953 head would require milling of about .060" to raise from 7.5 to 8.0--inlet valves would need to be recessed plus a few other minor changes.Sure you would never feel a gain in performance.
Gene Schneider
|
|
|
|
|
Joined: Jul 2003
Posts: 264
Backyard Mechanic
|
|
Backyard Mechanic
Joined: Jul 2003
Posts: 264 |
The Canadian 261 in3 six cylinder 'Strato-six' produced 148 BHP @ 4800 r.p.m.; 8.5:1 Compression Ratio in 1958, and then 150 bhp in 1959-62.
|
|
|
|
|
