Help on determining value of 842 heads.

RichSchmidt · #1 12-17-2023, 01:00 PM

I am trying to get some input on selling a set of 842 big block heads. I don't even mean a specific price but rather a comparison of how they compare to original 842 heads.

Here is the deal. These heads are fresh with good parts and have never been damaged or welded. They have no modifications to the ports or chambers orhere than a light radiysing of the intake port opening to match an aftermarket intake of simular size.

Here is the bad. I think these heads are later service replacement heads,maybe as late as 1970 and don't have the casting plugs on the ends of them which were found on the pre early 69 version. Second the exterior was polished and it removed the snowflakes.

I work at a high end race engine shop and the heads are there all fresh with brand new parts and ready to go. I will post pictures of part of them when I return to work on Monday. I see that mint 842 heads with early dates are selling for big money. My question is could I get 1/2 or even as little as 1/3 of those kind of prices or would the later dates (I am not 100% sure on that) and lack of snowflakes make them worth a lot less even if I can blast them to look cast?

I have seen mint early heads for north of 4k. I see that cheap aftermarket heads are over $1500 and aren't correct in any way for a restoration. Could I get 2k for them since they are bolt on and ready to run real GM heads?

RichSchmidt · #2 12-17-2023, 01:43 PM

Here is one more question. I have a way to restore t original finish at least to reasonable cast look. I can also add the plug to the front. All without disturbing the fresh rebuild. Would this help value or sellabity?

**COPO** · #3 12-17-2023, 02:19 PM

A huge portion of the value is due to appearance and the dates even though they aren't visible once installed, so yes if you can make them appear factory original with the "snowflake" it would go a long way to even making them sellable. Even with all of that I think you'd be lucky to get 50% value of a correct pair. The porting is going to hurt value as well even though it helps a bit on the power.

I think a lot of people interested in factory pieces are way more likely to pay up for a correct mint set rather than save some money and get the wrong dates and less than optimal appearance for their particular application.

RichSchmidt · #4 12-17-2023, 05:58 PM

Thanks. They will never have the snowflakes. I saw another set of NOS heads and they seem to have the same porting. I think it isn't porting but rather how the factory smoothed out the rough entry. The grind marks go less than an inch into the port. No actual opening of the ports was done. I figured that while they aren't correct dates and won't have the snowflakes they are still all fresh and ready to bolt on and have no repairs to them which nearly all the original heads have they might still be better than a lot of what's out there. Since even cheap Chinese aluminum heads are over $1,500 and have very poor quality of parts and machine work these heads might be worth something. I don't think these heads were ever on a running engine. They were on a show car that was never finished and the entire engine was brand new except the block and crank.

RichSchmidt · #5 12-18-2023, 07:57 PM

So I just had a chance to look at them. There are 2 sets of small numbers cast into the bottom of the heads. The first set is 6 7 8 9 10. The second set is 05010 the numbers are the same on both heads. What year were they made? I actually think these heads are brand new and never run. They were on a 1960 Corvette show car that never had the engine started. As for the ports I wouldn't say they are ported. A light radius was added to make them match the stock intake gasket. I will post some pics in a few minutes.

**Igosplut** · #6 12-25-2023, 02:05 PM

Are you talking about this style head on the left? (the other is an 074)

RichSchmidt · #7 01-03-2024, 05:43 PM

Quote:

Originally Posted by Igosplut

Are you talking about this style head on the left? (the other is an 074)

Yes,they are closed chamber,rectangular port aluminum

RichSchmidt · #8 01-03-2024, 05:47 PM

Quote:

Originally Posted by Igosplut

Are you talking about this style head on the left? (the other is an 074)

If they weren't polished on the outside they would be perfect in every way. As far as porting goes I see that youe exhaust ports have a light deburring which is about the same as the intake ports on these heads have so if your heads are untouched so are mine.

RichSchmidt · #9 01-03-2024, 05:58 PM

And just like your's they don't have the big pipe plug on the end of the head. This supposedly changed in early/mid 1969.

**Zman1969** · #10 02-20-2024, 01:51 PM

Rick, I bought mis-matched pair a 392 and a 842 that have had some mild porting had O-ring grooves repaired - had my machinist look at them and he said they had some nice machine work done to them by P/O with a $900 receipt from reputable shop in Austin that were still fresh from his shop done in 08 and have been stored since and were dusty unknown springs so we swapped springs paid $2600 for these numbers don't matter for me