[Alpines] Holbay head

[jarrid_gross at earthlink.net]

Tony,

If its trully a holbay head, there are two things to be said for it.

1) The intake ports will be very small, limiting top end power.

2) The combustion chambers are somewhat higher volume than the normal 1725
and without special flat top pistons, you will end up loosing compression ratio and thus engine power.


Now its been rather common to modify a normal 1725 head to Holbay specs, this of course ignores the smaller
intake ports, which obviously cannot be made.  In this case, you have the higher chamber volumes and subsequent
loss in mechanical compression ratio.


In order to function to H120 specs, you will need the head, H120 cam, alpine spec twin weber DCOE intake, and
the special holbay spec twin 40 DCOE carbs.


Jarrid Gross

-----Original Message-----
>From: Tony Somebody <achd73 at yahoo.com>
>Sent: Dec 13, 2009 12:03 PM
>To: Alpine List <alpines at autox.team.net>
>Subject: [Alpines] Holbay head
>
>I have a chane to buy a Holbay head  and want to use it on the 1725 Im
>rebuilding for my S5. Although I do have a couple of nice Alpines (my opinion
>of course) I have more Tiger knowledge,but w/ OD, my\this S5 was a ton of fun
>and it had great hiway speed, except with the 18 wheeler problem, it kept
>wanting to pass them at a high rate of speed. To bad the speedo cable was
>broken in half, I might have slowed down. NEways, is there any problems using
>the Holbay head Im unaware of? Im installing a cam reccomended by Jim Ellis. I
>had a relly nice stock head I spent hours porting and then sent out to have a
>pro finish it BUT the machine shop says I picked it up- funny I left the
>block. I think my buddies S2 has my head on the engine I sold him, as his
>mechanic had the engine and head in the same machine shop. If he ever blows a
>head gasket I will know for sure. LOL
>Thanks ahead of time for any help I may receive and happy Holidays to all.
>TonytheTiger
>_______________________________________________
>Support Team.Net  http://www.team.net/donate.html
>
>Alpines at autox.team.net
>http://autox.team.net/mailman/listinfo/alpines
>
>http://www.team.net/archive