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I have a 351M in my Bronco that I’d like to stroke to a 400, so I’m hunting a crankshaft. I found a guy selling a purported ‘77 F-350 with a purported 400. I asked for the block info to verify it’s not one prone to cracking and he came back with some really weird info. It looks like my 351 in the pictures, but I won’t claim to know much of anything on this. Can anyone make sense of the following pictures?
I can't make out that 2nd picture but that might be the code in question.
Besides, it's the crank you want, not the block unless your block is over bored already.
Hard to confirm it's a 400 without pulling the heads or the pan. Trying to go through the plug hole with a wire doesn't work well on those according to some.
The code, as best can be read, looks like GKG65273. The second G could be an 8 too. Doesn’t seem to line up with much unless it’s not a casting code. I didn’t see a foundry identifier either, so maybe this is some other designator.
The crank is all I need, but I’d love to find something I can rework while I run the 351 in the Bronco. Unfortunately I still have to positively identify the crank as a 400 and it is 3.5 hours away.
The metal engine ID tag is located under a bolt that retains the coil bracket to the intake manifold.
Or it's a sticker that is affixed to the right valve cover.
The number in the 2nd pic is not an engine ID number. What it refers to, I haven't a clue.
1977/79 F100/350 & 1978/79 Bronco 351M/400 share the same block and heads. The bore (4.00") is the same, the stroke is different: 351M = 3.50" / 400 = 4.00."
Measure the stroke to verify the engine size. The block casting number is D7TE-A2B or D7TE-6015-A2B
1977/79 Passenger Car 351M/400 have a different casting number. 1977/79: The 351M crank is the same as cars, the 400 crank is F100/350 & Bronco specific.
Thanks Bill. I'll inquire to see if he can find the ID tag under the coil. Even if it's a bad block, having a crank to work with may be worth the drive down there.
EDIT. Sorry, 85e150six4mtod is right. I just tried below procedure on my 400 and it doesn't work as well as with FE engines. The angle of the plug hole is too much to get to the piston at BDC. Somebody needs to spank me.
Measure the stroke. I've done this on FE engines, but never on a 335 block. But it should work the same except for the firing order. Remove #1 and I believe #7 spark plugs. Rotate crank to TDC on #1 cylinder. Put a dowel or straightened coat hanger through the spark plug hole on #1, until the top of the piston stops it. Put a mark on the dowel. Use a repeatable reference point on the head that is the same on #7. Also, make a mental note of the angle in which you inserted the dowel so you can repeat that same angle on the next step Then put the dowel in #7 (make sure dowel is long enough that you don't lose it in the cylinder). Make a mark on the dowel using the same reference point as you did on #1 cylinder. Then measure the distance between marks. 4" means its a 400. A 351M will have a 3.5" measurement.
Thanks for the input guys. I have a little more info to share:
Seller cleaned up the block stamping and indeed it does look like a GKGG6273. So that doesn't appear helpful.
He also provided the VIN off the doorjamb and the VIN is listed as F37SCO27165. What I've found is that this decodes to a 400 built in Ontario for the '77 model year, which is what he's claiming it is.
The engine is locked up. I would likely pull the pan and see if I can find a crank stamping, but there is a risk it's not accessible in the as-found position of the crank. Engine is already out of the truck.
If you guys see anything in this post that would give you serious doubt that this is a 400, let me know, otherwise I may take a flyer on it and see if I win or strike out.
He also provided the VIN off the doorjamb and the VIN is listed as F37SCO27165. What I've found is that this decodes to a 400 built in Ontario for the '77 model year, which is what he's claiming it is.
Pan off, it's easy to measure a 2" crank throw....
I've never tried it. I understand what to do, I suppose just have some concern that obtaining better than 1/4" resolution could be tough considering that centerlines aren't readily available and some OD to centerline guesses will be in order. But it's definitely something I will try so I can confirm what I'm buying.
Thanks to all who hung in this thread. I will likely pick up the engine if it's still available the next time I can get down to the seller.
I had a buddy who was down that way pick up this engine for me. Appears to have an NP435 4 speed hung off the back. It’s going to sit for awhile, but the casting code I published previously is definitely stamped on the block just to the passenger side of the oil pressure sender. I’ll update this thread when I get it cleaned up and ready for inspection. Thanks to all who chimed in.
Thanks again Bill. I double checked some other references and it does appear to be an NP435. It has an 8 bolt aluminum top cover. It’s too dirty to confirm any housing markings just yet.
Can anybody identify the white stuff in the coolant system? Brief reading says it may be an oil/water mix due to failed head gasket. It wasn’t in the upper hose and I haven’t dug into the block. Engine is seized but crankcase oil looks good. But that doesn’t mean anything as I don’t know operating history.
Get a crank kit from Auto Supply. 351 M blocks have the front cover cast with the block. 35`/5.8l have a aluminum front cover. they dont inter change nutin.
Scat sells stroker and cranks too
Got heads off. Engine still locked. Found standing water in rear driver’s side cylinder (#8, I think). Rusted up. Possible where the stuck is from. Only the starter and distributor are installed. All cylinders hosed down with Kroil for the night.
I did some rough measuring of piston depth. I have two pistons flush with the block. The piston most furthest away from the block surface is recessed 3.5”.
Am I premature in calling this a 351m instead of a 400? Did I take a gamble and come up empty?
4 speed hung off the back.
