good heads on a 400
Thread Starter
Member
Joined: Mar 2002
Posts: 309
Likes: 0
From: VA
good heads on a 400
hey guys, i was just wondering, what would be a good head/chamber size to go with for a 406. Im looking to keep TPI on it. Just with a hi-flo intake, SLP runners, and a heck of a ported plenum. I was also wondering what chamber size i would need to go with to get about a 9.7:1 CR. Also would 24lb/hr injectors be big enough for this beast. Oh yeah and the heads have to be affordable......That means about $1000
Supreme Member
Joined: Jul 1999
Posts: 18,457
Likes: 16
From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
Flow is everything with a big motor. Of course, with a TPI with that little mods, your RPM range will stay limited to near stock, so huge heads aren't the answer and will probably slow the car down.
Chamber size will depend on the pistons you use. I'd recommend 64cc heads and small dish pistons, shoot for a CR of around 10:1 if you use iron heads or about 10½:1 with aluminum heads. A runner volume of around 180cc should be plenty. Something maybe like Edelbrock RPM heads would be about the max.
24 lb/hr is not enough. If the motor would still be stock, you'd need 400/350 * 22 lb/hr, or a little over 25 lb/hr; if you want to make more power than just the same HP/CID you have now, you'll need more fuel.
Chamber size will depend on the pistons you use. I'd recommend 64cc heads and small dish pistons, shoot for a CR of around 10:1 if you use iron heads or about 10½:1 with aluminum heads. A runner volume of around 180cc should be plenty. Something maybe like Edelbrock RPM heads would be about the max.
24 lb/hr is not enough. If the motor would still be stock, you'd need 400/350 * 22 lb/hr, or a little over 25 lb/hr; if you want to make more power than just the same HP/CID you have now, you'll need more fuel.
Supreme Member
Joined: Sep 2001
Posts: 1,355
Likes: 1
From: MN
Car: 2009 Pontiac G8 GXP
Engine: LS3
Transmission: 6L80E
Axle/Gears: 3.27
Instead of upgrading your TPI...go all the way and get a Stealth Ram for the same $$$...
Believe me, you will be much happier....
I started my 406 with a stock plenum and runners (with Edelbrock base to mate to my older heads) and it had lots of torque, but then again, so does a diesel
Top end sucked...
For the money and simplicity, buy the Stealth Ram for $450 (with fuel rails) and go from there...
As for heads, I tend to say that a slightly larger cc intake runner is a better deal with a 406 (like 200cc minimum). The reason is that my 406 has been in a few different vehicles and in different versions (originally bone stock) and with upgrading, I have found that trading off a bit of low end torque (under 2200) for better midrange and top end (I shift at 5800 rpm) makes for better drivability.
The larger cubic inches means that you can afford to lose a bit of torque and still be ok...After all, you haven't talked about suspension mods yet...
HTH,
Believe me, you will be much happier....
I started my 406 with a stock plenum and runners (with Edelbrock base to mate to my older heads) and it had lots of torque, but then again, so does a diesel
Top end sucked...For the money and simplicity, buy the Stealth Ram for $450 (with fuel rails) and go from there...
As for heads, I tend to say that a slightly larger cc intake runner is a better deal with a 406 (like 200cc minimum). The reason is that my 406 has been in a few different vehicles and in different versions (originally bone stock) and with upgrading, I have found that trading off a bit of low end torque (under 2200) for better midrange and top end (I shift at 5800 rpm) makes for better drivability.
The larger cubic inches means that you can afford to lose a bit of torque and still be ok...After all, you haven't talked about suspension mods yet...
HTH,
Thread
Thread Starter
Forum
Replies
Last Post
NinjaNife
Tech / General Engine
27
Aug 23, 2015 11:49 AM