[Vrroom]

I'm trying to decide what cam to use on my 400 build for my 69 GTO. My last 69 GTO motor was a 400 (+.030) and had 062 heads, forged pistons milled .060, a RA III cam which was advanced 4 degrees, a 2200 rpm stall converter and a 3:23 rear end. Performance was not great, but it did have that lopy sound at idle, which is what I wanted at the time.

For this build I have a standard bore 400 and #96 heads measured at 96-98cc's. I'm going to mill them 0.060" in an attempt to get the CR higher. The deck height is + 0.010. I was thinking about using either a 068 or a 744 cam with a little less LSA (probably about 14 degrees instead of 15.5) and also advancing the cam 2 to 4 degrees. I'll probably go with a 2200 stall converter as well. The rear end gear is a 3:23 (open) at the moment, but that can easily be changed.

I really don't know WTF I'm doing. I've read too much stuff in the past month and now I'm confused. I'm just making a guess at the combination that I think might work. If any one has some suggestions, please feel free to post them now before I start spending money.

What I want is a car that sounds like a muscle car while it's idling. I'd like to have that "seat of the pants" feel from 0 to 40 mph, but the top end does not need to be strong. The car will be a daily driver and will be more of a toy than anything else. I will not be racing it at the local drag strip.

Thanks for any input or engine build combinations related to the parts that I have to build with.

Vrroom

[Vrroom]

I'm trying to decide what cam to use on my 400 build for my 69 GTO. My last 69 GTO motor was a 400 (+.030) and had 062 heads, forged pistons milled .060, a RA III cam which was advanced 4 degrees, a 2200 rpm stall converter and a 3:23 rear end. Performance was not great, but it did have that lopy sound at idle, which is what I wanted at the time.

For this build I have a standard bore 400 and #96 heads measured at 96-98cc's. I'm going to mill them 0.060" in an attempt to get the CR higher. The deck height is + 0.010. I was thinking about using either a 068 or a 744 cam with a little less LSA (probably about 14 degrees instead of 15.5) and also advancing the cam 2 to 4 degrees. I'll probably go with a 2200 stall converter as well. The rear end gear is a 3:23 (open) at the moment, but that can easily be changed.

I really don't know WTF I'm doing. I've read too much stuff in the past month and now I'm confused. I'm just making a guess at the combination that I think might work. If any one has some suggestions, please feel free to post them now before I start spending money.

What I want is a car that sounds like a muscle car while it's idling. I'd like to have that "seat of the pants" feel from 0 to 40 mph, but the top end does not need to be strong. The car will be a daily driver and will be more of a toy than anything else. I will not be racing it at the local drag strip.

Thanks for any input or engine build combinations related to the parts that I have to build with.

Vrroom

[b-man]

I have a standard bore 400 and #96 heads measured at 96-98cc's. I'm going to mill them 0.060" in an attempt to get the CR higher.

After milling the heads you wont get the compression up much past the high 8:1 range, probably very close to 8.8:1. A good compression ratio for running the engine on the currently available premium unleaded, you should be able to drive it hard without detonation worries.

What I want is a car that sounds like a muscle car while it's idling. I'd like to have that "seat of the pants" feel from 0 to 40 mph, but the top end does not need to be strong.

Herein lies the problem. Most guys want a radical sounding idle, but also want excellent bottom-end torque. You can't have both, it has to be a compromise between the two.

A radical or 'musclecar' idle comes from cams that generally have more top-end power.

Smoother idling cams have the best low-end power.

Using a radical cam with a somewhat low-compression 400 will not result a very good performing engine, but it will idle nasty.

Using a better-matched (smaller) cam in that same engine will result in excellent street performance (low-end and mid-range), but a less radical sounding idle. A nice sounding idle, but not the radical one that scares away potential competitors at the stoplight.

For your engine that is pretty much just a stock 400 I'd choose a cam that's in between the 068 and 744. Use the Crower 60241 (215/221,.457/464", 112 LSA). It will still have a decent little lope at idle, and you'll be pleased with the performance on the street.

Performance was not great, but it did have that lopy sound at idle, which is what I wanted at the time.

Sometimes less is more. Don't pick a cam because it has a nice idle, pick one because it makes your car move out like it should instead.

[TCSGTO]

Try some of the Isky line of cams. They have a tight 108 lobe separation to give that lopey sound at idle but make real good low end & mid-range power. I think they make one with around 216 deg at .050 and a 108 LSA with the intake lobe at 108.
I used a Crane 272 ( 216/228 @ .050 112LSA)in my then stock 400 and it ran very good but idled smooth too. It turned 13.60-.80 with stock intake/exhaust manifolds in a 3900 lb car on 225/70/14 radials.

[taalltheway]

I have a Comp cams XE 262 (218/224/110LSA)....very good lowend to midrange plus a rumbling idle. At least it sounds nastier than the stock cam...