hi i am trying to figure out what head i have i know it is a oval head .. the thing i am trying to find out is it a big oval head port or a small oval head port they both look the same to me... and im trying to put some side draughts on by today so please help!

here is my manifold:
http://i143.photobucket.com/albums/r1 ... AZIE_LOCZ/0427090909a.jpg

http://i143.photobucket.com/albums/r1 ... AZIE_LOCZ/0427090909b.jpg

http://i143.photobucket.com/albums/r160/KRAZIE_LOCZ/0427090911.jpg



and these are the ones it could be: except the gx one cus those are way to big

* Small oval (28 mm x 30 mm). The 1974 A13 has this design.

* Small oval with swirl obstruction. These are good for emissions and fuel economy

http://i143.photobucket.com/albums/r160/KRAZIE_LOCZ/4444.jpg

* Large oval (28 mm x 34 mm). These std A14/A15 ports are best for high-RPM operation, or for the bigger engines
http://i143.photobucket.com/albums/r160/KRAZIE_LOCZ/14888.jpg

http://i143.photobucket.com/albums/r160/KRAZIE_LOCZ/14886.jpg

http://i143.photobucket.com/albums/r160/KRAZIE_LOCZ/12714.jpg


NOTE: the top of the port comes up to the centerline of the top bolts

* GX oval (30 mm x 36 mm). From A12GX and A12T engines.


http://i143.photobucket.com/albums/r160/KRAZIE_LOCZ/9028.jpg

http://i143.photobucket.com/albums/r160/KRAZIE_LOCZ/12131.jpg

NOTE: the top of the port comes up as high as the top of the top bolt holes (port comes up past the bolt hole centerline)

GX Oval vs. A14 Oval Comparo :
http://i143.photobucket.com/albums/r160/KRAZIE_LOCZ/5215.jpg


Port Sizes
Ports Size (mm) Exhaust Raised Note
round 28 ? * no 1971 A12
round 28 ? lowered 1977 GFU
Oval - small 28x30 ? * no 1973 A13
Oval - large 28x34 ? no Many A14s
Oval - GX 30x34.5 - 36 27x29 Yes A12Gx (1971-1973)


please help me figure out which one i have have either small oval or large oval which one is it??????