small chevy 23 deg head port lengths.

[pastry_chef]

Greetings everyone.
This is a wonderful forum, obviously very many knowledgeable people here.

I was wondering if anyone may have actually measured the intake and exhaust port lengths of a 23 degree small chevy cylinder head?
For a typical smaller 200cc and under street head if it matters.

I'll do mine for sure next time my engine is apart.

Thanks.

[bill jones]

-here's a few that I have seen, flow tested at 25" and all these numbers are at .500" valve lift.

-SBC #186 head -------5.50"---174cc---211cfm---------------1.93avg SIA---262.4 FPS avg port velocity---109.3CFM per sq in
-SBC #993---------------5.19"---182cc---223-------------------2.14------------250----------------------------------104.3
-pontiac #867RI---------5.38"----247cc---274-------------- ---2.80 -----------234.9---------------------------------97.9
-Winston Cup 18deg.--5.44"---251cc---294------------------2.817----------252.5----------------------------------104.4
-Dart 2 cast iron--------5.31"----212cc---248-----------------2.436-----------244.3-----------------------------------101.8
-Dart 2 cast iron--------5.35"----219cc---248-----------------2.50------------238.1-----------------------------------99.2
-Dart 2 cast iron--------5.35"----237cc---260-----------------2.706----------230.6------------------------------------96.1
-351-2V Ford------------4.812"--180cc---248-----------------2.28------------260--------------------------------------108.8

[bill jones]

-I have never measured and kept any exhaust ports records so I don't have any to post

[pastry_chef]

Thanks Bill, that's awesome.

[speedtalk]

Hey pastry_chef, thanks for joining the forum. What's for desert?

[Harbinger]

Hi Bill Jones.

In your length measurements, I'm curious where those were taken? Mid-port, roof??

Just curiosity on my part.

Thanks,
Chuck

[bill jones]

-I use a narrow tape measure, cut off the first ten inches to get rid of the bent end, then I measure along the floor from the port inlet at the gasket face-to the bottom of the seat angle.
-then to do the roof I measure the same way but along both sides of the valve guide, and try to get a pretty good idea, add'm up and average out the length.
-It may not be exactly right but it's easy and repeatable.