Difference these heads will make?
Thread Starter
Racer
Joined: Nov 2003
Posts: 342
Likes: 0
From: Felton De
Difference these heads will make?
I've been thinking about replacing my heads for over a year now. I keep going back and forth but love the juggle.... I learn something every time i get the "itch" that makes this coming true all the more practical. Say I go from 72cc heads with 165cc intakes and baby 1.94/1.5 valves (Irong eagle SS heads) to a set of Dart Pro 1 alluminum heads with 200cc intakes, 64cc chambers, and 2.05/1.6 valves. I don't want to get overly into the vehicles components, but it has forged flat tops in an old two bolt main bored .030, a Holley 650 DP, and a crane cam (http://www.cranecams.com/?show=brows...tType=camshaft)
Aside from rough HP gains, do you guys think I'll feel a noticable difference after installation? How about low/mid/high? Do you think I'm right in my assumption that based on the given data my heads are the weakest link? Assuming so, how do I determine which gasket to use to achieve the "perfect" compression ratio without smacking the piston against the head?
Aside from rough HP gains, do you guys think I'll feel a noticable difference after installation? How about low/mid/high? Do you think I'm right in my assumption that based on the given data my heads are the weakest link? Assuming so, how do I determine which gasket to use to achieve the "perfect" compression ratio without smacking the piston against the head?
Thread Starter
Racer
Joined: Nov 2003
Posts: 342
Likes: 0
From: Felton De
Well, all things considered, if your using flat tops Id say your compression is probably close to mine.
I guess what I'm trying to get from all this is some type of assurance I'll be happy with the car when I'm done.... which of course no one can say. I have a full MSD ignition, but it still seems slow down low, and doesn't have the top end I believe it is capable of... all this w/ a 3.55 rear and 700r4 tranny. I want it to squeal the tires when i punch the gas and hopefully cover the 1/4 in the low 13's. I realize that might sound a bit blunt, but if I can have a good reliable classic that runs at or slightly above 13 flat, capable of always lighting em up from the stop, and gets 15+mpg then I'm set!
I guess what I'm trying to get from all this is some type of assurance I'll be happy with the car when I'm done.... which of course no one can say. I have a full MSD ignition, but it still seems slow down low, and doesn't have the top end I believe it is capable of... all this w/ a 3.55 rear and 700r4 tranny. I want it to squeal the tires when i punch the gas and hopefully cover the 1/4 in the low 13's. I realize that might sound a bit blunt, but if I can have a good reliable classic that runs at or slightly above 13 flat, capable of always lighting em up from the stop, and gets 15+mpg then I'm set!
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
Use a compression calulator to see what the smaller combustion chambers will do to you. Just plug in what you have now and then what you are thinking about. If pump gas is a concern do not supass a 8.2 - 8.3 dcr.
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
Use a compression calulator to see what the smaller combustion chambers will do to you. Just plug in what you have now and then what you are thinking about. If pump gas is a concern do not supass a 8.2 - 8.3 dcr.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,501
From: Little Rock AR
I've been thinking about replacing my heads for over a year now. I keep going back and forth but love the juggle.... I learn something every time i get the "itch" that makes this coming true all the more practical. Say I go from 72cc heads with 165cc intakes and baby 1.94/1.5 valves (Irong eagle SS heads) to a set of Dart Pro 1 alluminum heads with 200cc intakes, 64cc chambers, and 2.05/1.6 valves. I don't want to get overly into the vehicles components, but it has forged flat tops in an old two bolt main bored .030, a Holley 650 DP, and a crane cam (http://www.cranecams.com/?show=brows...tType=camshaft)
Aside from rough HP gains, do you guys think I'll feel a noticable difference after installation? How about low/mid/high? Do you think I'm right in my assumption that based on the given data my heads are the weakest link? Assuming so, how do I determine which gasket to use to achieve the "perfect" compression ratio without smacking the piston against the head?
Aside from rough HP gains, do you guys think I'll feel a noticable difference after installation? How about low/mid/high? Do you think I'm right in my assumption that based on the given data my heads are the weakest link? Assuming so, how do I determine which gasket to use to achieve the "perfect" compression ratio without smacking the piston against the head?
I would get the 64cc 180 Iron Eagles if you think you want to upgrade. Check your DCR as you may be getting close to the limit. Figure on using the .015" Fel-Pro steel shim racing gasket if at all possible. You want to shoot for about .040" head to piston top clearance so the quench stays nice and tight. That along with the heart shaped chambers on the Iron Eagles will help make the engine less octane sensitive.
Iron Cross makes a good suggestion about a solid lifter cam. You might look into that if you think that would work for you.
-Mark.
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Drifting
Joined: Mar 2001
Posts: 1,396
Likes: 6
From: Indiana
Aside from rough HP gains, do you guys think I'll feel a noticable difference after installation? How about low/mid/high? Do you think I'm right in my assumption that based on the given data my heads are the weakest link? Assuming so, how do I determine which gasket to use to achieve the "perfect" compression ratio without smacking the piston against the head?
Thread Starter
Racer
Joined: Nov 2003
Posts: 342
Likes: 0
From: Felton De
Ok, well, at least I have something to work with. 180cc iron eagles and a solid cam. I was really hoping to avoid installing a new cam. We'll see. I know I would benifet lots, but I was trying to do this myself, and heads I figured were within my ability, a cam might be stretching it, at least for now. Thanks for the input though.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,501
From: Little Rock AR
Ok, well, at least I have something to work with. 180cc iron eagles and a solid cam. I was really hoping to avoid installing a new cam. We'll see. I know I would benifet lots, but I was trying to do this myself, and heads I figured were within my ability, a cam might be stretching it, at least for now. Thanks for the input though.
The main thing is that in order to get faster, you are going to need more RPMs. The solid lifter cam will get you where you want to go. The hydraulic cam you have runs pretty well but a solid cam combo has more potential.
-Mark.
