Chevrolet 235 261 McGurk Ported Cylinder Head Inline Straight Six 6 Stovebolt

Description

Hello, this listing is for a completely rebuilt, ported cylinder head for an early Chevrolet inline six cylinder engine.
This head will fit all 1953 through 1962 235 and 261cid engines.
It has been fully rebuilt to run on modern unleaded fuel and ported using the methods pioneered by Frank McGurk in the 1950's.  In May 1955 McGurk Engineering did extensive dyno testing on a new 261 Chevrolet engine. That article was titled "Soup that Chev" and can be fond via a Google search. By porting the cylinder using his methods a gain of 15 peak horsepower was recorded.
The work done to this head is as follows:
Cleaning and Inspection:
This head has been hot tanked and magnafluxed.
It has no cracks or crack repair.
All threaded holes have been chased, and all freeze plugs have been replaced.
Porting and Polishing:
The process which I use to port the head is an exact replication of Frank McGurks.
The process works as follows:
·
All three intake ports are
enlarged
using a shell reamer.  The ports are taken out to 1 9/16. This is the diameter of the original centering ring for the intake.  Once
completed
this is almost 1/4 larger then the OEM port.
·
Underneath
the intake valve the port is opened up to 1 1/2.  Most castings have a major restriction here.
·
On the exhaust side the valve pocket is opened to  1 3/8.
Differing
from McGurks method here is required when using a modern hardened valve seat insert.
Machine Work:
The head has been completely machined and treated to a professional rebuild.
The work done is as follows:
·
New Thick Wall J-Loy cast iron guide inserts installed.
·
New SBI hardened valve seat inserts installed on the exhaust side.
·
Valve seats reground 3 angle  20-30-45-60 on the intake and 30-45-60 on the exhaust.
·
Surface milled .060.
This is a basic mill to get compression near the 9.00:1 point.
If you need assistance calculating your desired compression ratio or need the head milled more I will be happy to do so for no additional fee.
Parts and Assembly:
Sadly the engine rebuilding industry is flooded with cheap offshore made parts.
I use only the finest quality parts available.
·
SI Industries steel valves.
·
Pioneer Valve springs, seals and keepers.
·
K-Line valve guide inserts
About Vintage Engine Works:
I am a one man machine shop that specializes in rebuilding of all types of antique engines.
If your local machine shop is unwilling or unable to tackle your project I can.
If you are looking for a complete 235 or 261 engine I have cores and can build a turn key running engine to your specifications.
If you have any questions feel free to e-mail.