Would switching my heads make any difference?
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From: Toronto Ontario
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Would switching my heads make any difference?
I currently have the top end of my motor apart to fix a nagging oil leak, and I recently came across a great deal on a set of brand new AFR 195 heads. What I want to know is would putting these heads on my car really make a difference without changing anything else?
My current set up:
406 cu in
Comp cam XE274: Duration at 050 inch Lift: 230 int./236 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.487 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.490 in.
Lobe Separation (degrees): 110
Edelbrock Performer RPM air gap intake
Edelbrock Performer RPM heads
Holley 770cfm Street Avenger carb
This set up made 330rwhp and 380 rwtq. The AFR and Edelbrock heads are identical in every regard and spec except for intake port; the Edelbrocks are 170cc and the AFRs are 195cc. Would these heads make a difference?
My current set up:
406 cu in
Comp cam XE274: Duration at 050 inch Lift: 230 int./236 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.487 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.490 in.
Lobe Separation (degrees): 110
Edelbrock Performer RPM air gap intake
Edelbrock Performer RPM heads
Holley 770cfm Street Avenger carb
This set up made 330rwhp and 380 rwtq. The AFR and Edelbrock heads are identical in every regard and spec except for intake port; the Edelbrocks are 170cc and the AFRs are 195cc. Would these heads make a difference?
Last edited by 7t2vette; Mar 19, 2006 at 10:18 AM.
Le Mans Master
Joined: Sep 2001
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From: Unreconstructed, South Carolina
Sure, they'll make a difference ... but IMHO probably not enough of one to warrant the expense & time. The rpm 170's cost about what ? ... $900-$1000 ... the afr 195's? ... $1300-$1400. My guess ... guess ... is maybe a 20hp/25tq increase ... at best.
Race Director
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From: Millington Illinois
St. Jude Donor '08-'09
http://www.users.interport.net/s/r/srweiss/tablehdc.htm Here is a Chart for flow numbers. I think the heads and the 170 cc runners are your weakest point on an otherwise excellent build. If you are getting a good deal on the heads I would buy them and sell the RPM heads to someone with a 350 build. GO FOR IT! 
Bet it will get you 40 HP and 40 Torque or better with your combination. That 406 has got to breath. the 170 runners are choking it. I would bump up the cam a little if your comp ratio lends itself to an upgrade. What are the chamber sizes on the heads an what is your Comp ratio now?
Bet it will get you 40 HP and 40 Torque or better with your combination. That 406 has got to breath. the 170 runners are choking it. I would bump up the cam a little if your comp ratio lends itself to an upgrade. What are the chamber sizes on the heads an what is your Comp ratio now?
Last edited by 63mako; Mar 19, 2006 at 10:58 AM.
Melting Slicks
Joined: Feb 2003
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St. Jude Donor '03,'11
if your gonna go to the trouble why not go whole hog and get heads with even bigger ports?
You have a big engine with lots of cam so it should respond well.
you didn't say anything about the valve sizes.
You have a big engine with lots of cam so it should respond well.
you didn't say anything about the valve sizes.
Thread Starter
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From: Toronto Ontario
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Originally Posted by jackson
Sure, they'll make a difference ... but IMHO probably not enough of one to warrant the expense & time. The rpm 170's cost about what ? ... $900-$1000 ... the afr 195's? ... $1300-$1400. My guess ... guess ... is maybe a 20hp/25tq increase ... at best.
Melting Slicks
Joined: Feb 2003
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St. Jude Donor '03,'11
Originally Posted by 7t2vette
Well, I already have the old heads off the car, so time isn't an issue, just cost. I can get the AFRs for $800 brand new, but I don't plan on doing a cam change right now, so I was wondering if it was even worth doing at the moment. I figured the same gains as you did, I don't think I will see a significant gain without also changing the cam.
If you have time port your existing heads or have them done.
Thread Starter
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From: Toronto Ontario
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Originally Posted by 63mako
http://www.users.interport.net/s/r/srweiss/tablehdc.htm Here is a Chart for flow numbers. I think the heads and the 170 cc runners are your weakest point on an otherwise excellent build. If you are getting a good deal on the heads I would buy them and sell the RPM heads to someone with a 350 build. GO FOR IT! Bet it will get you 40 HP and 40 Torque or better with your combination.
Bet it will get you 40 HP and 40 Torque or better with your combination.
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by 7t2vette
Well, I already have the old heads off the car, so time isn't an issue, just cost. I can get the AFRs for $800 brand new, but I don't plan on doing a cam change right now, so I was wondering if it was even worth doing at the moment. I figured the same gains as you did, I don't think I will see a significant gain without also changing the cam.
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Thread Starter
The ORIGINAL and bestest
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From: Toronto Ontario
Toronto Events Coordinator
Originally Posted by turtlevette
if your gonna go to the trouble why not go whole hog and get heads with even bigger ports?
You have a big engine with lots of cam so it should respond well.
you didn't say anything about the valve sizes.
You have a big engine with lots of cam so it should respond well.
you didn't say anything about the valve sizes.
This motor really needs 200+cc heads.
Originally Posted by turtlevette
go to 1.6 rockers to get a little more lift. That is a pretty healthy cam for the street IMHO.
If you have time port your existing heads or have them done.
If you have time port your existing heads or have them done.
Thread Starter
The ORIGINAL and bestest
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From: Toronto Ontario
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Originally Posted by 63mako
If you don't want them for $800 I will take them for sure!! E-mail kevindjensen@sbcglobal.net
Last edited by 7t2vette; Mar 19, 2006 at 11:14 AM.
Melting Slicks
Joined: Aug 2004
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From: Keizer Oregon
I have my Performer RPM heads off right now as well......I thought about replacement but I decided to have them ported and polished/valve job etc.....the shop projects a 20+ CFM improvment....which should translate to a pretty good hp gain.....Just a thought..
Thread Starter
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From: Toronto Ontario
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Originally Posted by oregonsharkman
I have my Performer RPM heads off right now as well......I thought about replacement but I decided to have them ported and polished/valve job etc.....the shop projects a 20+ CFM improvment....which should translate to a pretty good hp gain.....Just a thought..
Thread Starter
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From: Toronto Ontario
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Originally Posted by 63mako
http://www.users.interport.net/s/r/srweiss/tablehdc.htm Here is a Chart for flow numbers. That 406 has got to breath. the 170 runners are choking it. I would bump up the cam a little if your comp ratio lends itself to an upgrade. What are the chamber sizes on the heads an what is your Comp ratio now?
It kills me to know that I have a killer bottom end in my motor, only to be choked by my heads!
What I really want to do is strap on a set of big 200cc+ heads and switch to a bigger full roller cam, but the funds for that aren't available at the moment, I only have about $1500 to play with right now, so I am leaning towards the Wildwood brake package instead. That being said, I will look into perhaps getting the RPMs ported/polished if it is cost effective. The RPM heads have a 70cc combustion chamber, while the AFRs have a 68cc combustion chamber, which would raise my current CR of 10.709:1 to 10.941:1
Le Mans Master
Joined: Jul 2005
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From: Austin Texas
I checked out the cost to port my Edelbrock Vic. Jr. heads, was quoted $900.00. If I were in your shoes, I would pop on the AFR 195's. I think it would be a good match for your cam and c.r.. AFR 210's would be better, but at $800, I couldn't pass them up.
Race Director
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From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by 7t2vette
Thanks for the link to the flow numbers, alot of good info there.
It kills me to know that I have a killer bottom end in my motor, only to be choked by my heads! What I really want to do is strap on a set of big 200cc+ heads and switch to a bigger full roller cam, but the funds for that aren't available at the moment, I only have about $1500 to play with right now, so I am leaning towards the Wildwood brake package instead. That being said, I will look into perhaps getting the RPMs ported/polished if it is cost effective. The RPM heads have a 70cc combustion chamber, while the AFRs have a 68cc combustion chamber, which would raise my current CR of 10.709:1 to 10.941:1
It kills me to know that I have a killer bottom end in my motor, only to be choked by my heads!
What I really want to do is strap on a set of big 200cc+ heads and switch to a bigger full roller cam, but the funds for that aren't available at the moment, I only have about $1500 to play with right now, so I am leaning towards the Wildwood brake package instead. That being said, I will look into perhaps getting the RPMs ported/polished if it is cost effective. The RPM heads have a 70cc combustion chamber, while the AFRs have a 68cc combustion chamber, which would raise my current CR of 10.709:1 to 10.941:1Last edited by 63mako; Mar 19, 2006 at 12:52 PM.
Thread Starter
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Originally Posted by big_G
I checked out the cost to port my Edelbrock Vic. Jr. heads, was quoted $900.00. If I were in your shoes, I would pop on the AFR 195's. I think it would be a good match for your cam and c.r.. AFR 210's would be better, but at $800, I couldn't pass them up.
The deal is very good, and I am having a hard time passing it up, but I don't think the 195's are really worth it because I don't think they are even big enough! AAARRRGGGHHH!!!!
Thread Starter
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Originally Posted by 63mako
That's pretty high CR for the street and pump gas. I would guess you are at the top of your Dynamic CR now to run pump gas. But the Edelbrocks are suffocating that engine. How do the ports match up to the intake? If you port or upgrade and have to do the intake too. Lot's of work. Sell your stuff and buy what you need. You can upgrade the heads and buy a cam to optimize your Dynamic compression ratio. A hydraulic roller with the right heads and you cold possibly pull 520HP 520TQ with what you got and the bottom end will hold up well. What you have in the bottom will live dependably for a long time with your existing top end. BULLETPROOF! Good build and let me know on the heads.
Melting Slicks
Joined: Apr 2004
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From: Montreal Qc.
Originally Posted by 7t2vette
Thanks for the link to the flow numbers, alot of good info there.
It kills me to know that I have a killer bottom end in my motor, only to be choked by my heads! What I really want to do is strap on a set of big 200cc+ heads and switch to a bigger full roller cam, but the funds for that aren't available at the moment, I only have about $1500 to play with right now, so I am leaning towards the Wildwood brake package instead. That being said, I will look into perhaps getting the RPMs ported/polished if it is cost effective. The RPM heads have a 70cc combustion chamber, while the AFRs have a 68cc combustion chamber, which would raise my current CR of 10.709:1 to 10.941:1
It kills me to know that I have a killer bottom end in my motor, only to be choked by my heads!
What I really want to do is strap on a set of big 200cc+ heads and switch to a bigger full roller cam, but the funds for that aren't available at the moment, I only have about $1500 to play with right now, so I am leaning towards the Wildwood brake package instead. That being said, I will look into perhaps getting the RPMs ported/polished if it is cost effective. The RPM heads have a 70cc combustion chamber, while the AFRs have a 68cc combustion chamber, which would raise my current CR of 10.709:1 to 10.941:1