Like the title says.... I have a 1975 f100 with the 360 eddy intake and carb with long tube headers. Cam unknown most likely stock. Odometer says 47,000 whatever that means.

Around town driving and highway driving the truck is responsive and sounds exactly like it should. If I take it on the freeway 55-60 mph for 5-10 miles and get off the freeway the engine sounds extremely pissed off. A lot of valvetrain noise. Last oil change I think I ran 10w40 with a Lucas oil additive to thicken it up a bit. But regardless before the oil change it did the same thing. Haven't done a compression test but I was just curious what your opinion was and if I have a rebuild in my near future. Thanks!

 

Do you have an oil pressure gauge. You need some vitals to troubleshoot.

 

Unfortunately just the stock gauge. It moves but I'll work on getting a good one hooked up.

 

This sounds like the typical FE problem of too much oil getting to the rocker shafts and flooding the heads, starving the rest of the motor.

Pull the valve covers and check that your oil drain holes are not clogged with pieces of valve stem seals

Two schools of thought on this - if the heads are flooding with oil, restrict the oil flow, usually with Holly carb jets put down the oil feed hole under the rocker shaft support stand.

Other school, replace the rockers and shafts, because the rockers and/or the shafts are so worn they aren't holding any oil pressure.

 

Krewat thanks for the reply! I'll pull the valve covers this week and check things out. Just ordered some gauges as well.