Big Block Cylinder Head Advice Needed
Thread Starter
Supporting Lifetime Member
Joined: Oct 2005
Posts: 454
Likes: 4
From: Lovettsville Virginia
Big Block Cylinder Head Advice Needed
I know there are a ton of threads with this similar question, but everyone's situation is a little different, so...need some advice on my engine build. It's a street (not raced) car.
I've got a rebuilt .060 over 454 short block with domed pistons (cr should be about 10:1 with stock 781 heads). I'm planning on upgrading the cam to a solid roller, but haven't picked which one yet.
I also have a set of rebuilt '781' cast heads (marked 'X' - what does that mean?). They are oval-port. I know I'll have to upgrade the springs for the roller cam if I stick with these heads.
I'm considering going with AFR 305's or 315 intake volume aluminum heads (rectangular port). My question is - is that the right head for my street car? Should I be looking at larger volume heads (>325)? AFR's website seems to point to these as a great street/torque monster. I have always heard that you should stick to oval-ports unless racing, but all AFR's are rectangular I think.
Am I wasting my money going with the AFR's verses just using what I have?
Any other recommendations or advice? Thanks!
I've got a rebuilt .060 over 454 short block with domed pistons (cr should be about 10:1 with stock 781 heads). I'm planning on upgrading the cam to a solid roller, but haven't picked which one yet.
I also have a set of rebuilt '781' cast heads (marked 'X' - what does that mean?). They are oval-port. I know I'll have to upgrade the springs for the roller cam if I stick with these heads.
I'm considering going with AFR 305's or 315 intake volume aluminum heads (rectangular port). My question is - is that the right head for my street car? Should I be looking at larger volume heads (>325)? AFR's website seems to point to these as a great street/torque monster. I have always heard that you should stick to oval-ports unless racing, but all AFR's are rectangular I think.
Am I wasting my money going with the AFR's verses just using what I have?
Any other recommendations or advice? Thanks!
Team Owner
Joined: Mar 2004
Posts: 24,202
Likes: 17
Oval port big Chevy heads are great for the street! You can do some port matching, polishing of bowl, install larger valves etc.... For the street, I really don't consider rec port heads necessary. If you really want to go up in rpm, and shave some weight I would go with rec port aluminum heads.
Not sure about the "x" on the heads
Not sure about the "x" on the heads
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
I know there are a ton of threads with this similar question, but everyone's situation is a little different, so...need some advice on my engine build. It's a street (not raced) car.
I've got a rebuilt .060 over 454 short block with domed pistons (cr should be about 10:1 with stock 781 heads). I'm planning on upgrading the cam to a solid roller, but haven't picked which one yet.
I also have a set of rebuilt '781' cast heads (marked 'X' - what does that mean?). They are oval-port. I know I'll have to upgrade the springs for the roller cam if I stick with these heads.
I'm considering going with AFR 305's or 315 intake volume aluminum heads (rectangular port). My question is - is that the right head for my street car? Should I be looking at larger volume heads (>325)? AFR's website seems to point to these as a great street/torque monster. I have always heard that you should stick to oval-ports unless racing, but all AFR's are rectangular I think.
Am I wasting my money going with the AFR's verses just using what I have?
Any other recommendations or advice? Thanks!
I've got a rebuilt .060 over 454 short block with domed pistons (cr should be about 10:1 with stock 781 heads). I'm planning on upgrading the cam to a solid roller, but haven't picked which one yet.
I also have a set of rebuilt '781' cast heads (marked 'X' - what does that mean?). They are oval-port. I know I'll have to upgrade the springs for the roller cam if I stick with these heads.
I'm considering going with AFR 305's or 315 intake volume aluminum heads (rectangular port). My question is - is that the right head for my street car? Should I be looking at larger volume heads (>325)? AFR's website seems to point to these as a great street/torque monster. I have always heard that you should stick to oval-ports unless racing, but all AFR's are rectangular I think.
Am I wasting my money going with the AFR's verses just using what I have?
Any other recommendations or advice? Thanks!
Last edited by Little Mouse; Nov 21, 2009 at 08:59 PM.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
IMCO, there's little reason to go with a solid roller unless you're planning to rev it up, in which case you ought to go with some respectable flowing rectangle port heads. But, since it will be on the street, I'd be careful not to go overboard on the cam/head combo and end up killing port velocities. The less time you spend with WOT or near the redline, the larger is this concern. Keep in mind that the better the heads flow, the less cam will be required to do the same job, and vice versa. And, it should go without saying that the optimum CR will depend much on that cam choice. The ~75# weight savings from going with aluminum BB heads is well worth having. And, if exhaust port location means anything to you, don't overlook that detail. Hope that info is more helpful than confusing.
FWIW, I'm in the middle (bogged down due to budgetary constrants) of a pump gas, alum head, solid roller, 427 BB build up myself, so I've given this stuff a bit of thought.
FWIW, I'm in the middle (bogged down due to budgetary constrants) of a pump gas, alum head, solid roller, 427 BB build up myself, so I've given this stuff a bit of thought.
Last edited by TheSkunkWorks; Nov 21, 2009 at 09:46 PM.
Melting Slicks
Joined: Oct 2008
Posts: 2,154
Likes: 69
From: Regina Sk Canada
I had the 305's on my 468, and they were too big for a street motor. Nothing under 5000 rpm. I spoke to Dart, and they have a killer set of oval port heads that would of been better for a 468. I had 12.0-1 compression and a .691/.684 lift .262/.272 @.050 solid roller. Call around, and go with oval ports you wont be sorry.
Melting Slicks
Joined: Jun 2001
Posts: 2,266
Likes: 550
You can't go wrong with AFR, just tell Tony what you are going to do and he will set you up. I bet he will tell you to go with the new oval port head. If you were racing or above 5000 rpm alot it would be the 305 with the cnc option. Or if you want a turn key engine at a great price call a company called Vortec Pro, 1-719-650-1609. Mike does outstanding work and is talked about at the team chevelle site alot. If I could sell my 460 BBC with the 990 Gm rect ports, I'd use him without a doubt. Ron B.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
You can't go wrong with AFR, just tell Tony what you are going to do and he will set you up. I bet he will tell you to go with the new oval port head. If you were racing or above 5000 rpm alot it would be the 305 with the cnc option. Or if you want a turn key engine at a great price call a company called Vortec Pro, 1-719-650-1609. Mike does outstanding work and is talked about at the team chevelle site alot. If I could sell my 460 BBC with the 990 Gm rect ports, I'd use him without a doubt. Ron B.
+10000000
I just got my 657hp pump gas, 049 ovals, hyd roller 496" from Vortecpro.....I will never buy an engine from anyone else.... Mine made within 4hp between two different dynos, 1500 miles away and 6300' difference in altitude...Best $8k you will spend on a motor....
Last edited by ajrothm; Nov 21, 2009 at 11:17 PM.
Racer
Joined: Oct 2006
Posts: 435
Likes: 18
From: Florida
Just something to think about if money is a concern, reworked iron will leave money for a hyd roller upgrade or cover most of it. If you have an oval intake thats more money to spend to go rect. For the street and the smallish cubes its probably the easiest and most cost effective way to go. The good ovals 049/781 heads can support over 500hp. If money is not a problem or you even think you will be doing something bigger in the future like a 509/540/565 than definately get the AFR's.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Thread Starter
Supporting Lifetime Member
Joined: Oct 2005
Posts: 454
Likes: 4
From: Lovettsville Virginia
I had the 305's on my 468, and they were too big for a street motor. Nothing under 5000 rpm. I spoke to Dart, and they have a killer set of oval port heads that would of been better for a 468. I had 12.0-1 compression and a .691/.684 lift .262/.272 @.050 solid roller. Call around, and go with oval ports you wont be sorry.
That's good to know. I'm not looking for a high rpm motor, but rather something with good low end and driveability. Do you happen to remember the which Dart heads they recommended?
Yes, money is always an object. But at the same time, spending a little money to go the wrong direction is worse than spending more money to the right way the first time. Sounds like I need to call around to a few manufacturers.
Thanks for all of the great advice?
Anyone else have any recommendations for a 468?
Thread Starter
Supporting Lifetime Member
Joined: Oct 2005
Posts: 454
Likes: 4
From: Lovettsville Virginia
Can you explain what this means? I see that some heads have a raised exhaust port, but I never paid attention to it. Does that affect how the manifold/header connects? I was planning to go with McJacks tubular manifolds that bolt up to the stock location of my side pipes. Will that be a problem?
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Yes, port location can cause fitment issues, depending on where they are and what you're connecting to them. Just making you aware before you learned on your own to watch for this potential problem.
Melting Slicks
Joined: Oct 2008
Posts: 2,154
Likes: 69
From: Regina Sk Canada
The nice thing with the oval port head, is they have a smaller runner which offers great air speed and more velocity. But they can be reworked to pull strong to 7000 plus RPM without killing your bottom end. I am not sure Which head it was that Dart had? You would have to call them up and ask them. Tell them your combo and your goal for the car and they will help you out i am sure.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
The 781 heads that you already have are really good street heads.
Have the rect port sized valves (2.19"i, 1.88"e) installed along with a bit of bowl port work done and they are even better.
If you have your heart set on aluminum heads, take a look at the Brodix oval port Race-Rites in addition to the Darts & the AFRs.
While all 3 make good performing heads, only the Race-Rites have the exhaust ports in the stock location.
Have the rect port sized valves (2.19"i, 1.88"e) installed along with a bit of bowl port work done and they are even better.
If you have your heart set on aluminum heads, take a look at the Brodix oval port Race-Rites in addition to the Darts & the AFRs.
While all 3 make good performing heads, only the Race-Rites have the exhaust ports in the stock location.
