67 trouble

[g68]

I have a 67 coupe with a 289 bored .40 over (i was told that this had the displacement of a 302). now there is a loud popping noise whenever it accelerates. it only happens when it goes over 2000 rpm, even when its parked. a friend told me that something was wrong with the valve seating, and i would like to know how to fix it. the engine has an edelbrock cam hydraulic lifters and gtp 40 heads. Also would a 373 ratio on the rear end help with the lack of acceleration?

 

[one2gamble]

you need to do better than "pop" , does it sound like metal hitting each other or is it a tick or is a pop. A pop would probably indicate that the engine is missing, this can be anything from a bad wire/plug to bad timing. The others could be valvetrain noise but they would normally exist even at idle. Another possibility is an exhaust leak that your just not hearing until its rev'd up.

 

[g68]

it sound like its back firing. i was told that it could be valve seating but i dont konw how to fix it less know what exactly is wrong.

 

[65fastback2+2]

or it could be as simple as carb mixture

 

[horseycar]

I also have a bored over 289 in a 1967 coupe. Mine would pop 4 or 5 times when I would hammer the accelerator. The problem wound up being bad timing and bad plug wires.

 

[mustangdave]

If it pops when you let off the gas, then it's probably an exhaust leak. If it pops when your on the gas, then your timing or carb is the most likely culprit. Make sure all of your vaccuum hoses are connected correctly also, especially the advance from the distributor.