Found 401m??
 

Hey everyone. Found possible 401m today. Was one the way back home from visiting family over the weekend and decided to stop at a junkyard that I knew had some 305's. Found a late 60's to early 70's 6500. Not able to find anything on the block but was in a hurry to get home. The data sticker on the glove box said it came with a 401m. I'm going to be going down next weekend to do some more looking. Biggest ? Is is there something in particular I need to look for. The price is right so I'll probably be buying the motor no matter what. I appreciate all the info that you can give me

Re: Found 401m??
 

Yeah check that engine block number to verify. I went to purchase a 351 and it turned out to be a 401M! Look for the trapezoidal carb mount on the intake too. Best of Luck :thumbsup:

Re: Found 401m??
 

Thanks for the info funky61. There's a power steering pump mounted right off the tstat housin so it was difficult to see the stamping on the block. Going down sat to pull that off and get some pics

Re: Found 401m??
 

Ok so I went to today and verified that the motor I was looking at is a 401m. Sad part is that it is locked up. I put the trans in neutral and put a socket and long breaker bar on balancer and was not able to move it. For the price I think I'll still get it. Since the trans is still attached not able to verify that it has a 6 bolt crank. What's the chance it has something else or is there just the one crank style. It has a Clark 282v 5 speed in it. Not sure if that really maters as far as crank goes. Read several threads on gaskets but what I understand is that everything is same as 305 except for head , intake and exhaust. What about internal parts I.e. main and rod bearings and cam bearings. There is several listed on eBay but they are listing all v6 engines using the same. Very few actually say just 351 and 401. About what would it cost to rebuild the motor

Re: Found 401m??
 

Some later 401 engines came with the 8 bolt crank too, you want the 6 bolt crank so you can use a 305 or 351 flywheel from a pickup truck. The good news is the 305, 351 and 401 engines all have the same stroke so you can use a crankshaft from a 305 or 351. The big difference is 305 and 351 crankshaft are cast Armasteel while the 401 crank is a forged. In a light duty application that should not pose a problem. That 401 appears to be locked up but doesn't necessarily mean it's the bottom end, moisture getting inside the cylinder bores from the intake or exhaust manifolds can build up a layer of rust in the cylinder walls then locking up the pistons.

Re: Found 401m??
 

I'm kinda hoping that's it. The motor is still in the truck. Its complete except only the base to the aircleaner is on. Ciuldnt find the rest of it. The radiator has been pulled but the top hose is still attached. Not sure about the lower hose. I don't remember it being there so it very well could be just rust in the cylinders. He also has another 401 laying in the dirt about 100ft behind the truck. It looks like it roll off the back of a truck going down the great lol. Good to know that cranks will interchange. I can get the 401m in the truck for 250. I might just get both. Surely he won't want more for the 401 sitting the dirt

Re: Found 401m??
 

If I were you I would definitely get both 401 engines:upyes:

Re: Found 401m??
 

Wow; Got two in one yard! Nice score :goodjob::coolphotos:

Re: Found 401m??
 

The one laying on it's side appears to be a 60-65 non Magnum 401.

Re: Found 401m??
 

Yes the one laying on the ground is just a 401. I posted a pic of both block serial #'s. It has a 60-62 hydraulic bellhousing on it. Yes it was a good day as both finds lol. Also saw a 64-66 gmc 1000 series truck for sale as I was getting into town. It looked pretty clean but was only able to look at it thru the fence.

Re: Found 401m??
 

Dang, you're in 60's GMC heaven! Definitely get both of those engines. I'd offer him $300 for both and tell him you might be able to tinker with it enough to get one engine out of the deal if you're lucky, since they don't sell parts anymore.

These are diamonds in the rough. He probably hasn't had anyone come by looking at them in years. There's GOLD in them thar' hills!

Re: Found 401m??
 

You want to know the funny part of all of this. We was coming back from visiting our daughter and grandkids. They live about 3 hours away. Anyways it was on Monday and I wanted to stop and talk to him. About 5 years ago I knew of about 3 305's and 1 351 that he had in his yard. When I told him what I was looking for he told that he was actually looking for a 401 also for a loader or something that I really don't remember what it was. Well anyways he told me that he didn't have anything. I mentioned that i knew about the other engines and then he told me to check this certain truck but didn't remember if it had anything in it. So I found the truck and it still had a v6 in it. We still had about a 45 min drive to get home so I just looked at it real quick. At this point I never saw the one laying in the dirt. I called him when I got home and he said he would sell it for core price. So technically he has 3 401's lol. I'm definitely going to get both engines. He also told me that at the end of April he's acquiring another junk yard that the previous owner was a cadillac and gmc collector. He told me to contact him then and I can go with him to look an see what's all in there:upyes: I'll let everyone know what I find

Re: Found 401m??
 

That last reference to another yard sounds quite interesting! May be more gold there too.

Re: Found 401m??
 

You couId fill a bus with all yer new best friends and take us with you on that wrecking yard tour.

Re: Found 401m??
 

Get out here and we'll go lol. He's getting all the gmc's. Supposedly the cadillacs are going over seas. I'll call him the end of this month beginning of may to see what's going on. I'll let everybody know

Re: Found 401m??
 

You're close enough I sure would like to, but I had to cough up $4k in taxes this year, 9k in ex wife bills, and I'm staring down the barrel of $6k worth of braces for the Powerpuff. Always the way with me. I'm so broke right now I can't pay attention.

Re: Found 401m??
 

I'm headed down Thurs to pick up the non magnum 401. Just curious is there pros and cons to either engine. Really hoping that the magnum once I get it out of the truck and home I can get it broke loose. What I've read on jollys site is the magnum produces more up but at higher rpm and less torq at a higher rpm. What's your guys thoughts

Re: Found 401m??
 

I can't swear but I think all's the same but fer the exhaust manifolds and intake options. Might be smoked up on that. . . . I bet ya someone will correct me if that's the case.

Re: Found 401m??
 

It's not all the same Magnum engines have larger port heads with bigger diameter valves, that's been common knowledge since the inception of JOLLY'S 6066 site.

Re: Found 401m??
 

I think you’d be ahead of the game either way long as you get a runner out of one.

Re: Found 401m??
 

Swat I'm thinkin.
I'd also wager you can't fool the forum.