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Hi guys, I just wanted to pass along some information that may be helpful to someone some day. I’ve had an odd motor sound coming out of my 1980 360. I’ve been around motors most of my life and I have never heard anything like this before. It was a high pitched clangy knocking sound. It was very predominate at the oil filler tube. I pulled the motor and took it to my local speed shop. They called me today to let me know that it was something wrong with the fuel pump arm! The pump is new and it took a year to happen. They are not sure as to why this happened but they said it’s wearing very odd on the internal part that drives the pump. Just another thing to check out! It was a good thing I pulled it out though because the previous owner claimed he rebuilt the motor, which my machinist said they did but they never reconditioned any of the rods. We will be reconditioning them or replacing them along with ARP studs to give me a better piece of mind.

I have seen a fuel pump make weird noises.

When they say it was wearing strange inside, do they mean the cam lobe? If that was the case, it almost makes me think the arm of the pump was made of hardened steel. Typically the arm should be softer than the cam, so the arm wears and not the cam.

Apparently that was just the beginning of the motor issues... I just got a call from the speed shop, they said I need a new block. The previous owner had at one point severely over heated it. Two of the cylinder walls are shot and to top it off it’s already at 60 over. Can someone please give me an idea of the years of motors that will work with my 80 j20? And will a 401 work with my set up? Thank you in advance.

AFAIK, any AMC V8 will drop in.

KJ Ryu wrote:AFAIK, any AMC V8 will drop in.

Well, almost. There are AMC "short deck" (66-70) and AMC "tall deck"(71-91) blocks.

Smkozma69 wrote:Apparently that was just the beginning of the motor issues... I just got a call from the speed shop, they said I need a new block. The previous owner had at one point severely over heated it. Two of the cylinder walls are shot and to top it off it’s already at 60 over. Can someone please give me an idea of the years of motors that will work with my 80 j20? And will a 401 work with my set up? Thank you in advance.

Technically any "3rd gen" tall deck AMC block will "bolt in", this covers the 304, 360, and 401. But I think accessory drive mounts changed at some point. But you should be safe with any mid 70's and up engine. The starter setup changed in the late 80's, but I don't think the block changed for this.

Thank you for the info. The hunt begins