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1967 400/400
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Discussion Starter · #42 ·
Alright, this will seem like a really dumb question, but have you verified that when you push your gas pedal to the floor, you are actually getting full throttle at the carb. The reason I ask is that I recently installed new ACC Essex carpet in my car. I also got some really nice floor mats (made with the thicker Essex carpet). The combination of the carpet and the floor mats are limiting my throttle so that in order to get kickdown to happen, I have got to push REALLY hard on the pedal. I am going to have to cut the floor mat so it does not interfere with the gas pedal.
Yes... That was an issue in my vette... so it's one of the first things that I checked!
 

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Discussion Starter · #43 ·
Hmmmmm. How old are you and how many loud exhaust cars did you think were really cool sounding - especially with wide open throttle?

Maybe its not the exhaust?????? LOL

An old man is concerned that his wife is starting to go deaf...

The old man goes to the doctor and says, "My wife can't hear very well anymore and I am getting worried. What should I do to help her?"

The doctor thinks for a minute and says, "First we need to understand how serious the problem is. Stand 25 feet away from her and ask her a question. If she doesn't respond, walk 5 ft closer and ask again. Repeat this until she can hear you and then let me know how far away you were standing."

The man is so concerned for his wife that he agrees to do what the doctor suggested. When he gets home, he sees his wife cooking in the kitchen. He stands 25 feet from his wife and says, "What's for dinner?"

The wife does not answer and he walks closer, "What's for dinner?"

The man does this 2 more times until he is standing only 5 feet from his wife. The man is now very worried and tries one last time, "What's for dinner?"

The wife looks over and yells at him, "I HAVE TOLD YOU 4 TIMES ALREADY, WE ARE HAVING LASAGNA!"
Yes... Im sure that 40 years of playing the bass in heavy metal band, racing motorcycles, shooting weekly, and hot rods... have not helped.
 

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Discussion Starter · #45 ·
this summer I did a top end refresh, from a crower 60916 and 77 heads on a stroked 421, to a crower 60919 with kre d ports. Exhaust remained exactly the same, rare manifolds, 2.25 pipes and dynomax ultra flows. The sound changed a lot which I am chalking up to the heads and bigger valves. Oddly enough, not much lope, which I thought that cam was going to give me more lope. Suspect it鈥檚 the 461 ci that is moderating that cam for lope.
My point overall- other things beside exhaust can change the sound too.

My new cam has a wider LSA, and that reduced the lope a tad, but it also has more exhaust duration and lift, so that beefed up the tone
 

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Discussion Starter · #46 ·
Here is a sound clip of mine. Yours sounds louder than mine which makes sense. Mine has a 461 with a Comp CE284H cam, 1.5 ratio rockers, factory cast manifolds (still waiting on the RARE manifolds to ship) and Pypes Race Pro mufflers (longer body 18").

Sounds beefy to me!! Must really roar when youre on it.
 

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You cannot compare a Chevy exhaust sound to a Pontiac. Chevy sound can be more crisp and snappy ad has a different pitch. Pontiac does not have that, period. To get a rough idle/lopey sound, just pick a cam with a lot of overlap like the RA IV cam - 87 degrees. Add a cam with 320 degrees of duration and you may have your sound. Plenty of rough idle/lope. Engine won't turn on until about 3,500 RPM's, and it will be real balky driving around town, but............you will sound cool if that is what you need.

You also have the AVS, not the Q-jet. The Q-jet offfers a different sound when kicked wide open and a different feel. Maybe go back to a Q-jet.

I think you should take it to a drag strip and get some times to see what it really does and measure it against your Vette or truck. Then you will know if you can determine the faster vehicle based on the exhaust note.
 

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nice, I like that

The placement of the muffler in the system can also have an effect on sound - another thing to play with as long as you have the clearance.

Here are a few examples of how this works.

 

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Just to provide some examples...

Below is a link to a video, shot by a friend of mine from his '71. His '71 has a moderately built 455 and runs a Demon carb. I mention that only because when he let me drive it once, I was blown away by how good the throttle response was. It was instant.

Anyway, a few years ago on a Saturday morning, we decided to do some "testing" with him in his car, me in mine. He shot this video. You won't be able to see my car at first, but you'll be able to hear it when the 'test' begins.

At the time this was shot, I was running Doug's round port 4-tube headers into 2 1/2" Pypes exhaust, X-pipe, and their RacePro mufflers. 461, Comp solid roller cam, 236/242 @ 0.050 tappet lift, 110 LSA, 1.65:1 rockers netting me right at 0.600 lift at the valves. 455 SD Qjet, Torker 1 intake. I do have electric cutouts on the car but they were closed during this video.

He shot this video. You won't be able to see my car at first, but you'll be able to hear the lifters when I pull alongside him, right before the 'test' begins. 馃榿

About 10 years ago, not long after I first got it running and driving, I shot this one. It's a walk around. At about 1:30 I start it, and at about 3:00 you can hear what it sounded like with the cutouts open. Running everything almost 'the same' as when my friend and I did our test. The differences were that on this earlier video, I was still running iron #722 heads and a port-matched factory intake. I would have preferred to have kept it that way, but a problem that occurred later with one of the heads forced me to replace them with 72cc round port E-heads, which also forced me to change to the T1 intake because my factory intake wasn't tall enough to cover the ports on the new heads.

Bear
 

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Discussion Starter · #56 ·
lol! It sounds awesome, everywhere! I took a video of mine without the xpipe and with the new cam... but it's too hard to tell the difference because it wasn't a controlled environment. I can definitely hear that the lope is less radical with the new, wider LSA. I also need to get a buddy help me with some revving and take-offs. Gopro stuff...

 

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lol! It sounds awesome, everywhere! I took a video of mine without the xpipe and with the new cam... but it's too hard to tell the difference because it wasn't a controlled environment. I can definitely hear that the lope is less radical with the new, wider LSA. I also need to get a buddy help me with some revving and take-offs. Gopro stuff...


You want me to drive up to NJ and give you a hug? Sounds like a Pontiac. Lope comes from Overlap.

Option #1 - Throw in a RA IV cam with 87 degrees of overlap and you will have your lope. Add 3.90 gears to make it streetable and a 2,800 stall converter.


Option #2 - Sell the GTO and buy a 1967 Big Block Chevelle.


Option #3 - Install a BB into the GTO.

 

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Discussion Starter · #58 ·
I told Butler I wanted the biggest cam that my car would run, and they said the cam they gave me was as big as they'd put in a 400. Yes, as you and I discussed, my LSA increased, moving my power band up and helping my lope to disappear... However, the new cam also ditched the 4/7 swap and it increased exhaust lift and duration, so it was one step back and two steps forward! I REALLY would love 355 gears, but Im already cruising at 3400 rpms.

As for driving to NJ for hugs, you can come here and help me work on the car. We'll see where it goes from there.
 

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Discussion Starter · #59 ·
HOLY BLOOP! Realized that the exhaust gasket on the driverside header was blown out on the center ports. Went to tighten the rear bolt and it spun in the breeze. Went to remove the bolt and cannot get a wrench on it. I have every tool known to man... but nope!

So last time I installed headers on a pontiac was 1995. DO I need to pull the steering shaft to get at that 3rd bolt?

I will have to pull down the dougs header, tap and helicoil the head, and reinstall. At this point it seems like I need to pull the motor.
 

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Army: "As for driving to NJ for hugs, you can come here and help me work on the car. We'll see where it goes from there."

LOL

Butler was plying safe and practical. You can always go bigger, but the results could be as disappointing as going too small. Remember Goldielocks? Butler gave you the "just right" cam not knowing you or your engine build.

A roller cam, in my opinion, does not seem to have the same sound as a flat tappet cam because of the BIG differences in lobe shape, the fast ramp opening, the longer amount of time the valve can be held open, and the fast closing.

Go flat tappet, and go solid. Get a cam with 320 degrees of duration and .530" - .550" lift if your springs can handle it. You should have a nice lope with that kind of duration and the overlap that comes with it. Then idle the engine down as low as you dare with out it stalling (and have reasonable oil pressure). You can get more out of a manual trans than auto. The lowered idle will also bring out the radical sound of the cam.

Assuming you still have the 10:1 or so compression ratio to use a big cam.

The power range will probably be 2,500 - 6,500 RPM's, but limit the RPM's so you don't pop your engine. Get a higher stall converter, and have fun. See below.

If you would let go of some of that cash roll you keep in your pant's front pocket and purchase a quality "tight" 2,500 - 2,800 RPM stall converter, it might put a smile on your face. It'll put the engine right into the lower power range of the cam bypassing the "not so big HP" of the under 2,500 RPM range when you nail the gas. It should pull well enough that you will forget about your rear's gera ratio. It'll still easily cruise with little slip and not heat up the trans or the fluid and won't kill gas mileage. But when you nail the pedal - it will take-off.

You know you won't be doing the 4-speed/5-speed swap anytime soon. May be a couple years. So let go of some of that cash and buy a converter. Should be around $350.00. You won't be driving the car much in winter in the snow at some point and you need something to do rather than sit around the house wrapped up in your Hello Kitty house coat eating cannoli's and watching soap opera's.

Or, bring it to a trans shop and let them swap it out in a day. (y)
 
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