487 vs. 487x heads

JRyan · 11-29-2013, 08:22 PM

Mac,

I simply don't know. I've never measured the cc's of a 487X to see how they compared to a 487, but I'm pretty sure the port sizes aren't as different as 461 and 461X's ( I think 7cc's now, and it used to be like 10 cc's different).

The casting dates on one of the 487X heads I have is 1971, so it could be that they were used on California cars which may have had a different EPA requirement for unleaded fuels in the early 70's that would have required the induction hardened seats. I think you'll notice on the head that the exhaust valve spring cup is deeper than the intake. They used the same spring on both int & exh., and just sunk the cup. That might have been one of the reasons for designating the "X". Later heads used shorter springs on the exhaust and the same cup depth.

All speculation on my part, but I'm sure there is someone out there that actually knows.

I'm with Greg on the 993's.

Jerry

Bill Bogues · 11-29-2013, 08:56 PM

I think the 993's are better than the 487's

John Scott · 11-29-2013, 09:08 PM

Interesting...thanks guys.

Adger Smith · 11-30-2013, 05:02 PM

Jerry,
Figure this one out.
I have a core supplier that hunts castings. The DT racers around here like the 487X head. He said he had several sets of castings that had 993 on the VC side, but in the water passage hole in the deck it had 487X. Could it be the lower part of the mold was for the 487X and they just mated the 993 top of the mold to them? Economy measure by the casting foundry? Use what they had available? I've always thought the X stood for a blueprint change. I wish I had some of thos 993/487X castings just to look at. Humm...

JRyan · 12-01-2013, 12:25 AM

Adger,

I just looked at one of those 993/487X heads today while arranging my storage. I think they're close to being interchangeable being they're both hard seat heads. GM must have thought so too as they interchanged molds for both as I've seen 993 in the VC area and 487X on the intake runner too. Some of the 993's also have a 493 on the bottom.

Also, I've had a pair of 993's with 152 cc runners. I'll bet the boys with the "Cheatin Bastards" would like those.

Jerry

Adger Smith · 12-01-2013, 01:18 AM

Jerry,
Wouldn't it be bad to get tossed with a 993 head and they see that 487X on it when doing the CC's... Humm
I'm going to have to run that one by Wesley.

Dwight Southerland · 12-01-2013, 11:12 PM

Not unknown on SBC heads. I have seen 291s with 462 cast on the bottom water passage hole.

11-29-2013, 08:22 PM	#1
JRyan Senior Member Join Date: Apr 2003 Location: Aberdeen SD Posts: 645 Likes: 30 Liked 112 Times in 31 Posts	Re: 487 vs. 487x heads Mac, I simply don't know. I've never measured the cc's of a 487X to see how they compared to a 487, but I'm pretty sure the port sizes aren't as different as 461 and 461X's ( I think 7cc's now, and it used to be like 10 cc's different). The casting dates on one of the 487X heads I have is 1971, so it could be that they were used on California cars which may have had a different EPA requirement for unleaded fuels in the early 70's that would have required the induction hardened seats. I think you'll notice on the head that the exhaust valve spring cup is deeper than the intake. They used the same spring on both int & exh., and just sunk the cup. That might have been one of the reasons for designating the "X". Later heads used shorter springs on the exhaust and the same cup depth. All speculation on my part, but I'm sure there is someone out there that actually knows. I'm with Greg on the 993's. Jerry

11-29-2013, 08:56 PM	#2
Bill Bogues Member Join Date: Apr 2005 Location: Bethany La. Posts: 323 Likes: 98 Liked 169 Times in 53 Posts	Re: 487 vs. 487x heads I think the 993's are better than the 487's __________________ Bill Bogues 4696 STK

11-29-2013, 09:08 PM	#3
John Scott Junior Member Join Date: Apr 2009 Location: New Brunswick, Canada Posts: 69 Likes: 1 Liked 0 Times in 0 Posts	Re: 487 vs. 487x heads Interesting...thanks guys.

11-30-2013, 05:02 PM	#4
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: 487 vs. 487x heads Jerry, Figure this one out. I have a core supplier that hunts castings. The DT racers around here like the 487X head. He said he had several sets of castings that had 993 on the VC side, but in the water passage hole in the deck it had 487X. Could it be the lower part of the mold was for the 487X and they just mated the 993 top of the mold to them? Economy measure by the casting foundry? Use what they had available? I've always thought the X stood for a blueprint change. I wish I had some of thos 993/487X castings just to look at. Humm... __________________ Adger Smith (Former SS)

12-01-2013, 12:25 AM	#5
JRyan Senior Member Join Date: Apr 2003 Location: Aberdeen SD Posts: 645 Likes: 30 Liked 112 Times in 31 Posts	Re: 487 vs. 487x heads Adger, I just looked at one of those 993/487X heads today while arranging my storage. I think they're close to being interchangeable being they're both hard seat heads. GM must have thought so too as they interchanged molds for both as I've seen 993 in the VC area and 487X on the intake runner too. Some of the 993's also have a 493 on the bottom. Also, I've had a pair of 993's with 152 cc runners. I'll bet the boys with the "Cheatin Bastards" would like those. Jerry

12-01-2013, 01:18 AM	#6
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: 487 vs. 487x heads Jerry, Wouldn't it be bad to get tossed with a 993 head and they see that 487X on it when doing the CC's... Humm I'm going to have to run that one by Wesley. __________________ Adger Smith (Former SS)

12-01-2013, 11:12 PM	#7
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 2,002 Likes: 64 Liked 783 Times in 195 Posts	Re: 487 vs. 487x heads Not unknown on SBC heads. I have seen 291s with 462 cast on the bottom water passage hole.