1966 327/275 cyl head cc

Jim Hawkins · 11-30-2019, 01:04 AM

Looking at the cylinder head cc the 461x is listed as 172cc intake and 64cc exhaust. All others are 165cc and 65cc. But then there is a note that says port volumes based on "X" head. Does this mean for example a 041 head can be 172cc intake port?
Also what is the best intake to use? I have a 3875954.

kansas stocker · 11-30-2019, 11:47 AM

The only 461x heads that I have seen came off of vette engines. They all had 2.02 intakes and 1.60 exhausts. The chamber is slightly different from the 461, supplying extra clearance around the valves. Looks like it would be a huge advantage on the 275 hp engine if you replace the seats to use the smaller valves. Pete

Dwight Southerland · 11-30-2019, 05:05 PM

I have harvested several sets of 461X heads off early 1962 327-300hp engines.1.94 & 1.50 valves.

bigsixman · 11-30-2019, 06:04 PM

[QUOTE=Dwight Southerland;602996]I have harvested several sets of 461X heads off early 1962 327-300hp engines.1.94 & 1.50 valves.[/QUOTE

I have seen the same 461X heads on 62 327/300 hp engines and with the small valves.

HP HUNTER · 11-30-2019, 06:16 PM

Never seen a 461 X with 2.020/1.60 Valves. Always 1.940/1.50.

Rich Biebel · 11-30-2019, 07:52 PM

There were really very few small blocks that came with 2.020 and 1.600 valves, OEM...compared to the millions of engines built over the years

I also never saw any 461x heads with anything but 1.940 and 1.500 valves myself.

Many of the real early 1960’s castings were somewhat poor quality. Material seemed soft and the head bolt bosses were easily damaged.
Splits, cracks and other flaws were pretty common. Used to see spots that were welded by the factory occasionally to save a casting. Valve cover rail , deck, head bolt boss.

HP HUNTER · 11-30-2019, 09:36 PM

A 461 X casting is a completely different port when compared to a 461 port.
A friend of mine just did a set of 461 X heads, with a 2.020 valve with just cutter work and rolling the short turn the head flowed 233 CFM, a 461 with the same work will never see that kind of flow.

Jim Hawkins · 12-01-2019, 12:18 AM

Thanks for the replies and PM's. To those who sent PM's I can not seem to get my private message reply to work. But thanks for the info.

Alan Nyhus · 12-01-2019, 09:58 AM

Jim, I got the pics you emailed me. I can't speak to the 461X heads as they aren't an accepted casting for my '68 327-275 combo. The book is a bit grey on the port volume...on one hand it appears that you can use the 461X @ 172 cc intake. On the other hand, it says the port volumes for heads are calculated on the 461X head when the 462's, 041, etc. are shown as 165 cc. And they all carry the same h.p. factor. Hmmmm...

While I sure wouldn't want to give up 5 cc's on the intake, the exhaust side is pretty important, also.

-Al

Greg Reimer 7376 · 12-01-2019, 11:50 AM

Do you see any difference between the 041 head and the 462 as to port improvements to air flow on one vs. the other? Is one better to start with than the other, outside the fact that the 041 might have a greater group of applications?

11-30-2019, 01:04 AM	#1
Jim Hawkins Member Join Date: Jan 2010 Posts: 186 Likes: 82 Liked 109 Times in 32 Posts	1966 327/275 cyl head cc Looking at the cylinder head cc the 461x is listed as 172cc intake and 64cc exhaust. All others are 165cc and 65cc. But then there is a note that says port volumes based on "X" head. Does this mean for example a 041 head can be 172cc intake port? Also what is the best intake to use? I have a 3875954.

11-30-2019, 11:47 AM	#2
kansas stocker Member Join Date: Oct 2002 Location: kansas Posts: 230 Likes: 419 Liked 233 Times in 44 Posts	Re: 1966 327/275 cyl head cc The only 461x heads that I have seen came off of vette engines. They all had 2.02 intakes and 1.60 exhausts. The chamber is slightly different from the 461, supplying extra clearance around the valves. Looks like it would be a huge advantage on the 275 hp engine if you replace the seats to use the smaller valves. Pete

11-30-2019, 05:05 PM	#3
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 1,980 Likes: 53 Liked 724 Times in 177 Posts	Re: 1966 327/275 cyl head cc I have harvested several sets of 461X heads off early 1962 327-300hp engines.1.94 & 1.50 valves. __________________

11-30-2019, 06:04 PM	#4
bigsixman Member Join Date: Sep 2012 Location: Crookston, MN Posts: 157 Likes: 8 Liked 2 Times in 2 Posts	Re: 1966 327/275 cyl head cc [QUOTE=Dwight Southerland;602996]I have harvested several sets of 461X heads off early 1962 327-300hp engines.1.94 & 1.50 valves.[/QUOTE I have seen the same 461X heads on 62 327/300 hp engines and with the small valves. __________________ 1969 camaro, pump gas 540"bbc, jerico 1967 camaro, pump gas efi 620", coan t-400

11-30-2019, 06:16 PM	#5
HP HUNTER Senior Member Join Date: Feb 2012 Location: Colorado Springs Colorado/Thousand Oaks Ca Posts: 606 Likes: 68 Liked 238 Times in 97 Posts	Re: 1966 327/275 cyl head cc Never seen a 461 X with 2.020/1.60 Valves. Always 1.940/1.50.

11-30-2019, 07:52 PM	#6
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,275 Likes: 25 Liked 510 Times in 200 Posts	Re: 1966 327/275 cyl head cc There were really very few small blocks that came with 2.020 and 1.600 valves, OEM...compared to the millions of engines built over the years I also never saw any 461x heads with anything but 1.940 and 1.500 valves myself. Many of the real early 1960’s castings were somewhat poor quality. Material seemed soft and the head bolt bosses were easily damaged. Splits, cracks and other flaws were pretty common. Used to see spots that were welded by the factory occasionally to save a casting. Valve cover rail , deck, head bolt boss. __________________ Rich Biebel S/C 1479

11-30-2019, 09:36 PM	#7
HP HUNTER Senior Member Join Date: Feb 2012 Location: Colorado Springs Colorado/Thousand Oaks Ca Posts: 606 Likes: 68 Liked 238 Times in 97 Posts	Re: 1966 327/275 cyl head cc A 461 X casting is a completely different port when compared to a 461 port. A friend of mine just did a set of 461 X heads, with a 2.020 valve with just cutter work and rolling the short turn the head flowed 233 CFM, a 461 with the same work will never see that kind of flow.

12-01-2019, 12:18 AM	#8
Jim Hawkins Member Join Date: Jan 2010 Posts: 186 Likes: 82 Liked 109 Times in 32 Posts	Re: 1966 327/275 cyl head cc Thanks for the replies and PM's. To those who sent PM's I can not seem to get my private message reply to work. But thanks for the info.

12-01-2019, 09:58 AM	#9
Alan Nyhus VIP Member Join Date: Dec 2002 Location: Lower Dakota territory Posts: 1,166 Likes: 1,018 Liked 762 Times in 226 Posts	Re: 1966 327/275 cyl head cc Jim, I got the pics you emailed me. I can't speak to the 461X heads as they aren't an accepted casting for my '68 327-275 combo. The book is a bit grey on the port volume...on one hand it appears that you can use the 461X @ 172 cc intake. On the other hand, it says the port volumes for heads are calculated on the 461X head when the 462's, 041, etc. are shown as 165 cc. And they all carry the same h.p. factor. Hmmmm... While I sure wouldn't want to give up 5 cc's on the intake, the exhaust side is pretty important, also. -Al __________________ "That'll never work....."

12-01-2019, 11:50 AM	#10
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,111 Likes: 164 Liked 649 Times in 208 Posts	Re: 1966 327/275 cyl head cc Do you see any difference between the 041 head and the 462 as to port improvements to air flow on one vs. the other? Is one better to start with than the other, outside the fact that the 041 might have a greater group of applications?