7, 14, 21, big valves, for TF?

Benjamin · backyard mechanic Joined: 05 Oct 2001 Posts: 525

I remember someone (Ben, Krem) saying that the number stamped on the head near the fuel pump (blank on earlier models) determines the valve sizes.

My TF has 14 or 21 (can't remember) stamped, and I have noticed a little difference between my TX and the TF. My TX was numbered 4, and it just seems the TF opens up a bit more. When I nail the throttle it gets an even greater induction roar than the TX did, for what I am assuming are almost identical engines.

When I took off from my dad's after putting the carb on, he noticed that it sounded different and went harder, throatier in sound. So, would this be a large valve head, and if so, does it really make as much difference as I am perceiving?

She is in the exhaust shop at the moment, getting my extractors and 2 1/4" system from my TX put on. I can't wait!

Thanx

Frosty · newbie Joined: 01 Nov 2001 Posts: 2

I asked around n what i can find out the cast number on the head relates the the year of the car. Numbers 14 or so on has the pollution gear coming from the head which can easily be blocked. The lucky numbers do have big valves. They should all open up the same amount but to get good flow u need a cam and match port the bitch.
If u are in brisbane go see Ivan Tighe Performance at West End. There the best for gemini cams as Ivan raced Gems for quite some time.

Slug · tinkerer Joined: 06 Oct 2001 Posts: 196

And to answer to original question .. the TF has smaller valves then the TX Smile

... Michael

darla · rice boy Joined: 11 Oct 2001 Posts: 23

Fish has 2 big valves in a Sigma head
44mm and 36mm.

Woz · tinkerer Joined: 05 Oct 2001 Posts: 126

that casting number theory is wrong - ive found heads with large valves that have numbers other than 7, 14 and 21.

There are plenty of tx's out there with different numbered heads. go to the wreckers and check it out. pull off a few heads and see for yourself.

i dont know who came up with the 7, 14 and 21 idea but i think they need to do some more research....

Adam · Site Admin Joined: 04 Oct 2001 Posts: 682

According to George Sheppard (who has been racing geminis since his Holden CDT days) the 7, 14 and 21 casting numbers indicate the large valve heads... I Spent a lot of time chatting to him (mostly at GSA wholesale suspension) about geminis and he was very adamant about this... He even had a pollution head (air pump and all) with big ports which had a 14 casting number and sure enough... stock big valve head... I was stunned too, never knew they existed. Ring/email GSA if you don't believe me... (www.gsad.com.au)

TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

wat darla meant was i have two heads
one has the gemi big valves
and the other has the 46mm and 36mm sigma valves in it
both for sale

TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

if the head is off the car turn the damn head over and look at the numbers on the valves you want the head that has 00XXX on the inlet This is a big valve head.
just read the damn workshop tips for more info

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

I have two TD heads with big inlet valves, they dont have 7, 14, or 21 on them.

flatchatcharlie · rice boy Joined: 08 Nov 2002 Posts: 38

I'm glad the 7,14,21 theory is wrong I have 3 tx engines head no. are 5,6,23 I also have another motor dont know what model with no. 20 so I 'll stop searching and check out the ones I have