How to identify heads?

[fireroad]

I was wondering if there is a guide or trick to identifying which engine a head came off of? I’ve got two spares I’m looking to sell and want to make sure I’m listing them correcting. One is stamped 1980987, 4H66, then AM. The other is stamped 1980813, 4F62, then AM2.

Any help would be greatly appreciated!

 

[junkman]

The higher #s are the later parts, 4H66 SV 4F62 SII

 

[Gordon Holsinger]

I was wondering if there is a guide or trick to identifying which engine a head came off of? I’ve got two spares I’m looking to sell and want to make sure I’m listing them correcting. One is stamped 1980987, 4H66, then AM. The other is stamped 1980813, 4F62, then AM2.

Any help would be greatly appreciated!

There are pretty easy the first is the day the second is the month the third is the year the forth is the shift at the foundry am or pm!

 

[fireroad]

The higher #s are the later parts, 4H66 SV 4F62 SII

There are pretty easy the first is the day the second is the month the third is the year the forth is the shift at the foundry am or pm!

That's quite a handy numbering system, thanks!

Pardon my ignorance, but I'm new to tearing down a motor and sometimes the more I read the more confused I get... are all the aluminum heads for each year basically identical with the exception of the SI through SIV heads having smaller valves and the rear water port? All can be used interchangeably regardless of engine size (but earlier heads would slightly reduce compression on a 1725)?

 

[RootesRacer]

All can be used interchangeably regardless of engine size (but earlier heads would slightly reduce compression on a 1725)?

The earlier heads used on a 1725 would actually increase compression ratio but with the smaller valves, the net effect would probably lower power.

 

[RootesRooter]

When were valve sizes changed on 1725's? I always thought the Arrow Range kept the same valves.

The earlier heads used on a 1725 would actually increase compression ratio but with the smaller valves, the net effect would probably lower power.

 

[fireroad]

When were valve sizes changed on 1725's? I always thought the Arrow Range kept the same valves.

When I referred to “earlier heads” on a 1725 I meant heads from the 1492 and 1594 motors. I did read in a another thread on this forum that some of the earlier 1725 motors from the factory had the smaller valves used it previous motors, but it sounds like there weren’t that many or it don’t last very long. Makes sense that they would have some leftover heads from the 1594 and used them on the first run of the 1725s.