1957 3731539 fi heads
 

Is there a way to identify or distinguiah between the heads used on the 57 corvette and those used on the 57 passenger cars?

Thanks

NOPE!!!!
Well, sorta.
The heads, blocks, and other cast iron parts were made in two locations, Tonawanda and Flint (Flint castings came from the Saginaw foundry).
Castings from Flint had date codes that ended with ONE number for the year, such as B237 for Feb 23, 1957. Tonawanda castings had TWO numbers for the year, such as B2357.
Thus, if a 539 head came from Flint, it could have been on EITHER a car or Vette. Whereas, a Tonawanda head ONLY went on a car.
The 539 heads for Vettes were ONLY on FI engines. And 539 heads on 57 Chevy cars were used on BOTH the power pack engines (4bl carb) and FI engines. Thus, 539 heads were VERY, VERY common on 57 pass cars.
Sooooooooooooooo, to have a CORRECT 539 head on a 57 FI Vette, it must be a Flint head.

And then there were the ...997 heads used on the 250 HP FI's and 2x4 engines. Same principles apply that DZAUTO described. Have heard of people paying very high prices for these rare ($$$$$$$) heads for their Vette, only to learn they were not from Flint.

1957 3731539 fi heads
 

Thanks for that info.

Mine are dated C227 & C257. does the X that is cast on the exhaust port side have any meaning that you know of?

Dwight

Thanks for that info.

Mine are dated C227 & C257. does the X that is cast on the exhaust port side have any meaning that you know of?

Dwight

In addition to the difference in the "year" portion of the casting date format (which can't be seen without removing the valve covers), Flint heads have the surface of the casting symbol on the end of the head machined flat, perpendicular to the deck surface, and Tonawanda casting symbols aren't machined at all - they're just the as-cast rough surface. The Flint head is on the left in the photos below. :thumbs:

:iagree: These heads are hard to find and can be very costly. You see very few on the internet or at the parts shows. I never did see a set at Auto Fair this weekend in Charlotte. Building a 1957 Bel-Air 2dr hardtop that originally came with these heads and a 2x4 setup with 270hp and a 3 speed after the 59 Corvette is finished.

Originally the FI heads had a light valve which were swirled on the port side. If I remember correctly the valves had a thin edge and would not take many valve jobs. I posted this only for information as finding a real set with original valves would be unlikely. The 997 heads also used these valves. At least on the HP engines.
Regards

I need to check the pair I have, see exactly what they are.

:thumbs:

Thanks for all of the info. I have had these heads for many years. No one commented on the X that is in the cast. Any one have any info on it?

Thanks for all of the info. I have had these heads for many years. No one commented on the X that is in the cast. Any one have any info on it?

Thanks for all of the info. I have had these heads for many years. No one commented on the X that is in the cast. Any one have any info on it?

An "X" generally was used to indicate to the customer (the engine plant) that there had been a foundry process change of some sort in that initial run of castings. After the engine plant machined them and found no issues, the "X" was removed from the pattern. :thumbs:

Thanks John,
Will probably have them worked and put em up for sale.

Dwight

I dug up an old thread. I found it looking for info on my 3731539 heads with the X on the exhaust side of the heads. Also one nice 3755550 casting. I have a few 461 462 941 040 186 292 041 ........ pm me if youy are looking for dates. Alot of the heads have been machined for hard seats, screw in studs, and new guides. Right now anything is for sale....

I wonder if this is true for the Power Pack engines too? My heads had valves which were thin as you describe. We ended up replacing them as we though it was a overly aggressive hand lap job from the past although the engine only had 24K miles on it.

The swirl polished valves John mentioned are easy to spot. Obviously there is the swirl polish....easy to see. Also, look at the portion of the stem just behind the valve and note whether it is necked down from the diameter of the upper part of the stem. If it is, then you've got one of the special valves.

Jim