Cylinder Head Question

Hi All,

I would like to have a ported fast street head done by one of our expert forum members. The problem is that my car is a daily driver and I understand that the turnaround time is about one month. I am thinking about buying a used head and sending it, then keeping my old head as a spare after it is changed.

My question is are there any casting #'s that are better then another? I understand that there were a few years of big valve heads. Would they be a better base?

This is for my 1974 1/2 GT.

Cheers,
Larry

Call or email Sean at Flowspeed.

http://www.flowspeed.com/

Call Sean Brown and ask him which head to use. I know he's bought several different castings from me for different applications so discuss first which casting will best suit your purpose. Does Florida require you to have the smog equipment intact? Sean's number is 541.582.6118. If you need a head, I have them or I can send one directly to Sean. Basil

Larry, mine is one of the cylinder heads whose P&P job Sean documents on his web site. Not only can he answer your question about the right head to use, you'll be absolutely delighted when you get it back and installed.

Hi All,

It was Sean I contacted but I just asked if he had a built head that I could buy and he did not.

No smog problems or inspections on a anitque in Flordia.

Larry

Antique? Ahem.... Don't you mean, ummmm.... Classic? ;)

No Rick,

Any motor vehicle in Florida over 30 years old is considered an antique, my licence plates say antique.

Actually, I think it's the same here in Virginia. My wife didn't buy it when I told her I was a classic, either. Antique all the way, sigh.....

Yea me too!

I remember going to the showroom to look at a new bugeye sprite!

Larry,

I had this same conversation with Sean that you are. I was wondering if I should buy this engine that had an "L" head on it.

He told me that it didn't really matter whether I got a big valve head or not, as he would be machining it to the best possible flow characteristics anyway and it didn't matter what we started with as they would both end up the same way.

So, In MY opinion finding a good head that is NOT cracked for a reasonable price is your best bet.

Sean will then work his magic and you'll end up with the best possible head you can get. the prices were the same, it didn't really matter where he started.

so, a crackless early head would be good.

B

Yes, I just got off the phone with Sean and he did say any eary head would be fine.

Larry

I just got my "Peter Burgess Head" from www.BritBits.com. It is a '66 for my '69 motor.

Yumm.... Engine porn. Shame on ya, Brad. :thumbsup:

Larry, you've obviously got some decent options to look at. Here's an example of some of Sean's work:









With a little peek at the "before"....

The early heads have a larger combustion chamber volume (43cc) so you can use the shallow dish pistons for about a 9 to 1 compression ratio. If you are just changing the head and have the deep dish pistons then an old head (12H906 no air injection ports) will give you about a 7.7 to 1 compression ratio. You don't want that. In that case you need to use a 72 or newer head (39cc). Your 74 1/2 should have the desirable 12H2923 with the bigger intake valves. Pop the valve cover and look for the number. Any of the heads can easily be converted to the larger intakes.