Originally Posted by super98lsc
Got ya so not driving it right now? What did they or you find wrong with the 360, you had mentioned it had the same nasty tap that mine has cold. Figured those 401 being forged had fairly strong crank, rods,pistons. Is there a need to go with k1 rods and custom forged slugs? Curious because figured later I would build a nicely blueprinted 401 short block and just swap it. 41+ cubes in a 4400lb barn going down the road should make a world of difference in torque. was your 401 bored, honed for larger pistons?
My 360 had some loose carbon get itself wedged itself into a valve. It gave it a knocking sound and I assumed it was the typical rod bearing. I still need to rebuild the heads and assemble it. The stock bore looks great so I will hone and re-ring it.
As far as the tapping some AMC guys said try swapping a known good pair of bridged rockers on each hole to check for a bad set. They can cause the sound we hate.
The 401 is great as a power plant.
A seasoned AMC guy I met up with at the Lufkin AMC meet have me a sharp piece of advice. Build your engine to be capable of 1,000 RPM over your intended use. That will make for a long lasting engine that can be accidentally downshifted, held in gear too long, or revved up by an idiot friend who "borrows it to move something" and sees some hot chicks at an intersection.
Consider it pre-marital counseling for your engine. It won't guarantee a long lasting relationship. But it can sure help solve some problems right off the bat. And you'll both be much happier with each other along the way.
I wanted to run 1,000-5,500 RPM. That means 6,500 proofing it. 5,200 is the max I would run the stock oiling system. So a Milidon, or Canton pan would work. Maybe a valley line oil mod if the engine is already out and going to get machined.
Second. Nobody should spin the stock or any cast plugs over 6,000 RPM. So forged plugs would be in order.
Third the stock forged crank and rods are stout (390 rods are actually stronger) but they need either reconditioning or replacement for high RPM's and ARP rod bolts. Mains are probably fine unless your running a 600HP Monster.
My 401 was bored .30 over was honed very nicely and made a pleasant amount of torque. It would carry me over any incline or ledge and it never had to pass 2,000RPM . But I have addictive tendencies and remember being a kid in my friends Dad's Vette. He told me to touch the dash and every time I tried he punched it. I was ten and the sensation of being stuck in my seat was amazing. I am still chasing that dragon.