Concerned about car sound after upgrades.

jerthemost

Member
Sep 9, 2012
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I just wanted to run this by you guys to see if you have any thoughts on the subject. My 68 mustang recently got performance upgrades. I had a blown head gasket so decided to upgrade the heads to new edelbrock e-street heads and in install the matching edelbrock cam also. I had an over heat problem so there was question about steam holes being drilled but that is another thread on here. But car went back in the shop about the holes so have not driven it but a couple of times since upgrade. And here is my question…….

I don’t think it sounds right when running. At idle it does have a good throaty smooth idle sound with just enough variation to tell the cam is there. At least I assume it’s the cam. But under acceleration it has more of a putt putt sort of sound. Plus I think it sounds like what I think a very large exhaust leak would sound like. Sort of like if you could hear exhaust hitting against something. I thought it would probably sound more like the high rpm smooth acceleration sound in the dodge challenger commercial. That sound that makes you think of power. The car is also much louder inside now than it was before, I would say twice as noisy.

The mechanic says I do have a cracked exhaust manifold, which he tried to weld up, and says it’s not very big. I had no crack there before the work as far as I know. I have a 302 engine with 289 innards with the edelbrock heads, cam and performer intake with 500 cfm edelbrock 4v on it. Stock cast iron headers with fairly new dual flowmaster exhaust.

they did find that the plugs were wrong, too short, when they pulled a head back off to check for the steam holes. Correct plugs are being installed. Could the plugs have made it sound like a putt putt? Or could it be timing or mixture? If timing is wrong I hear that can cause over heating or if mix is to lean also.

I have just put over $3000 into this car and have not been able to use it and it is back in the shop again. Hopefully will be back out this week and I can then tackle the heat issue if it still has one. I will post the heat issue as a separate thread. Thanks for any and all input.
 
Timing can be a contributing factor to overheating. Also a too small radiator. Have you upgraded your radiator to handle the extra heat your new found power will produce?

I had a professionally built 347 stroker built for my car. The car ran like a scalded cat. But it overheated so badly (even with a 3-core Desert Cooler) that the ceramic coated headers discolored. Turns out, the builder installed the head gaskets 180 degrees out. All my coolant passages were blocked.

Fast forward a few years. I had a small exhaust leak at the O2 sensor bung and it made the exhaust note sound just like you describe. This was exacerbated by the fact I had a torn shift boot so the sound had a direct path to my ear.

My advice is to get the exhaust buttoned up before doing anything major. Take it to a muffler shop with a good reputation for working on our Classics and have them search for leaks.

You might also check for a miss due to a bad plug wire. Or perhaps the correct length spark plugs will take care of all of this.
 
thanks

I did find some wires that appeared to be loose at the distributor and seated them but did not help. Was probably just loose boots. Wires are fairly new but of course one can go bad.

I am going to take it to a shop for the cracked exhaust maybe that will help also. If it is such a small crack i just didn't think it should be so loud.

i will be posting a thread on the heat issue in a few minutes because i do think i will have to install electric fan to boost my mechanical fan when stuck in traffic so would like to have your input on that issue. i have several questions about it.
 
Headers

I have been considering putting new headers on it and thought this might a good time to that since i have a leak. That should help get that exhaust out and help thise upgrades but I'm not sure what to get. I have been looking and the price range varies quite a bit. I can't afford expensive ceramic right now and have been told that the steel usually leak and are very hot in the car. But i did meet one guy in person with a 65 with steel headers and he said he doesn't haave any problems at all, no leaks and no extra heat.

So what do you think?
 
I had steel headers in my camaro with 425 horsepower, didn't have any heat problems, but since you outsource your work I would save money and get the ceramic ones....can get costly paying someone to replace headers for you. I got a set of ceramic coated patriot performance headers (full length) for 300 bucks, not too bad seeing how i have seen them average around 500, have had them for a year now and they are holding up great. Also +1 to what 2+2 said...even a tiny crack can be really loud and annoying, also need to double check the gaskets, they could have burned through at the head or at the donut.
 
A belt driven fan with a properly fitted shroud should provide plenty of air flow through the radiator. The question is, is your radiator up to the task? With what has happened so far, I'd argue it is marginal at best. This is a big deal and will affect your enjoyment of the car. Get yourself at least a 3 core radiator and put this problem to bed.

People say steel headers get hotter than ceramic and that may be the case. What is left out of the discussion is that both get HOT. Often you get what you pay for, so you need to decide where your comfort point is regarding headers. You could just replace the broken piece and save some money. Header repair is hit-or-miss and is probably not a good idea.

With the savings, you can invest in a QuietRide setup to keep the heat out of your car along with the sound.

There are some additives you can put in the coolant that make a large difference. The name escapes me right now.