[Holeshot71]

Originally Posted by gtofreek

The brand new manifolds out of the box were warped BAD! When I set them on the granite slab, there was probably a .040" bow in them. This has been the case with most of these manifolds I have installed new. So we took them and surfaced the gasket surface until they were flat. The steel gasket should work fine with them. Out of the box I could see you having to use the Fel-pro blue header gaskets or some Remflex. After surfacing them, they were flat so there should have been no need for special thick gaskets.

What I meant by surface mismatch was the exhaust ports were not lined up with each other and the gasket didn't crush. I believe it was a corner of one of the end ports.

I'm not saying this is the problem, it's just something I came across on the 455 I just built and thought it might be something to check.

When I'm listening for noises I prefer to use a 3' section of 3/8" rubber hose, one end to my ear. It really helps to isolate surrounding noises and helps to pinpoint where a noise is the loudest.

[Sirrotica]

Originally Posted by Holeshot71

What I meant by surface mismatch was the exhaust ports were not lined up with each other and the gasket didn't crush. I believe it was a corner of one of the end ports.

I'm not saying this is the problem, it's just something I came across on the 455 I just built and thought it might be something to check.

When I'm listening for noises I prefer to use a 3' section of 3/8" rubber hose, one end to my ear. It really helps to isolate surrounding noises and helps to pinpoint where a noise is the loudest.

As you have come late to this post, On page 13, post # 249 I also suggested using a length of hose to pinpoint the source of the noise. Using a length of hose I'm fairly certain they at least will pinpoint the exact portion of the engine transmission assembly where it is coming from. I've been turning wrenches for close to 50 years and have used this method when other methods were inconclusive.


My post from page 13:

As long as you have the new balanced flexplate by all means install it. I really have little faith it's going to cure the noise though. I feel you're in the right area, but if the noise gets cured by changing the flexplate it would be some other issue other than a crack, such as too much run out touching something on the rear side of the engine.

I'm not sure if you've tried a stethoscope, or used a rod to listen for the noise, but it sometimes will point you in the right direction. One other thing I have used to listen to automotive noise is a 1/4 inch piece of vacuum hose placed in your ear, and moving the other end of the hose around to pinpoint a noise. This method is probably better for getting you in the area where the noise is loudest, than listening with a rod or a stethoscope.

Just thought of one more thing, the welded lugs on the torque convertor. I have seen an instance where the lug was fractured. The car was a race car, actually the middle picture in my signature, 67 GTO, so with open exhaust no telling if there was a noise or not. The lug actually finally pulled a section of the torque convertor out, and caused all the ATF to leak out and burn on the hot exhaust system. One of the tack welds on the lugs could have broken off and caused a noise from the movement. Not likely, but this isn't a common noise either.

Hopefully the crew will be assembled this next weekend, and the mystery can be put to bed. I'm sure everyone that has money and time invested will be exceedingly happy to see the noise corrected.