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Max cubic inch out of a 401
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Hurst390 View Drop Down
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Points: 5822 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Hurst390 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2021 at 10:13am
I believe it was Fred Brewer that made deck spacers and had a 500 early on. I had pictures posted on the old forum.
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amxblair View Drop Down
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Points: 7 		Post Options Post Options   Thanks (0) Thanks(0)   Quote amxblair Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2021 at 11:50pm
Any chance of re-posting those pictures of FBS 500" AMC iron block?
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Points: 5121 		Post Options Post Options   Thanks (1) Thanks(1)   Quote Rebel Machine Quote  Post ReplyReply Direct Link To This Post Posted: Oct/23/2021 at 7:12am
Originally posted by amxblair amxblair wrote:

Any chance of re-posting those pictures of FBS 500" AMC iron block?


I copied and saved the 500" Herman Lewis photos.
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Points: 1007 		Post Options Post Options   Thanks (0) Thanks(0)   Quote motorhead_1 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/23/2021 at 8:27am
wow! too bad prices still aren't like that. dang! 
seems awful cheap by today's standards
who's got a time machine??
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Hurst390 View Drop Down
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Points: 5822 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Hurst390 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/23/2021 at 9:38am
Originally posted by amxblair amxblair wrote:

Any chance of re-posting those pictures of FBS 500" AMC iron block?
I believe they are held hostage by my photobucket account. I couldn't find them otherwise
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DragRacingSpirit View Drop Down
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Points: 903 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DragRacingSpirit Quote  Post ReplyReply Direct Link To This Post Posted: Oct/24/2021 at 3:00pm
Originally posted by motorhead_1 motorhead_1 wrote:

wow! too bad prices still aren't like that. dang! 
seems awful cheap by today's standards
who's got a time machine??

I was looking at the prices on that invoice as well.......wow.
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Points: 140 		Post Options Post Options   Thanks (0) Thanks(0)   Quote i6cj7 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/24/2021 at 6:02pm
Originally posted by Ken_Parkman Ken_Parkman wrote:

I have seen one at exactly 500.0 cubic inches, stock block and crank. It did run, but AFIK was not successful.

I have seen an extremely top notch engine at 463 cubic inches, worked well and went fast for years.

These combo's are not streetable.

For usable multi-purpose engines I like the typical "Detroit" combo 426 with a .030" over 4.195" bore and 3.85" stroke. Large bores are counterproductive for strength and in my opinion lose power, even .030" is pushing it if you intend on abusing the engine. The 3.85" stroke fits very nicely in a stock crank, nice if your grinder indexes the stroke away from the nearest oil feed hole. There have been stock cranks ruined by hitting the oil feed with more aggressive offsets. It also makes for a nice piston with a 1.265" CH when using a 6" rod.

The 4" Molnar crank does work but is a little tighter to fit the rod and piston assembly below the deck. Needs a 1.2" piston with the same rod.


If at .040 over, what's considered pushing it, power or boost wise? Mine sonic checked ok. Just curious. 
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Points: 1814 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken_Parkman Quote  Post ReplyReply Direct Link To This Post Posted: Nov/24/2021 at 6:51pm
You will find lots of different opinions including a lot that say boring a 360 to 4.165" is fine, and clearly it has worked well for many people.

At one time I was a pretty serious bracket racer, and was into the thousands in passes, and cracked a couple bores. Also seen it in other race applications. So this is why I made the above comments. The best block is the thickest walls, and that is no overbore. When I did the PHR Enginemasters engine I used a service 360 block (401 casting) at an underbore of 4.125" to get thicker walls. Engine worked pretty good, 1.38 ft-lb/in on pump gas.

BTW an extra .010" bore is 2 cu inch, worth about 3 hp on a good running 600 hp engine. While I do not have the data to back it up pretty sure any loss in wall stiffness will lose more power than that. So I always suggest the smallest reasonable bore. Of course if it takes .040" to clean up the block that's what you do. Boosted I would bore it the smallest possible to clean it up, or even better find a service block to get the bore down, but I'm more race oriented.

The AMC has a "scalloped" water jacket where the cylinder wall has thick and thin sections. The 401 casting has thicker thrust sides than an overbored 360, why it is not preferred to bore a 360 block to 401.

BTW none of this matters on a street cruiser. It does make a difference on an application that makes some power that you intend to abuse.
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Points: 2589 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 74Bubblefender Quote  Post ReplyReply Direct Link To This Post Posted: Nov/24/2021 at 7:08pm
Big CC and AMC 401 should not be in the same sentence. However we did 5 honda journal motors. I dont think any of them were under 600hp and as far as I know all of them are still running. BUT as Ken pointed out...they are weekend street engines. Thats where the vast majority of interest is. I also agree with Ken about the bores and useful HP on purposeful motors for strip use. But honestly lets face it passions are high in the AMC world where mathematics are often not really a major consideration. It was funny back 15 years ago when so many got queezy about honda journals. It was simply .050 more per side of the journal. And that seems to scare people into defensive positions. But we did it right...machine, grind, cryogenically treat, nitride and straiten. There were no shortcuts at that level and it was interesting. But what does 600ft lbs of torque and 630hp get you...a lot of H O L Y S H I I I I TTTTT
We are just about to forge new AMC V8 crankshafts.. please check here
http://www.bulltear.com/forums/showthread.php?19564
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Points: 6917 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Nov/24/2021 at 9:50pm
Will add to this, mathematically, with bore, stroke, cylinder pressure, cylinder flow restrictions, intakes ... a 360 with forged internals, including crankshaft, will out perform most built 401's.
For that matter, a 343 with forged internals, the shorter stroke and modern parts should out perform a 360 for a race engine, built for sustainable 8000 RPM.
The sweet spot is approximately 42 degrees BBDC exhaust open when the cylinder pressure maximizes the piston speed on a 4.100" bore, on "paper".
Many will only consider the intake close as the best power "moment". Agree, to the point when you have sacrificed too much combustion pressure, all based on RPM goals.  
Smaller rod journals = less friction and more RPM capabilities. Again, forged 343 crankshaft is the winner. 360 forged internals are a close second.
For a race engine.
Win a lottery and I'd build a 343 with the upcoming 3.44 forged crankshaft, ported Edelbrock heads, Victor JR intake ...  and the current 401 would be shelved back in the 70's as the ultimate AMC engine.
You would have to put a 3.44 forged crankshaft and all the goodies in a 401 block to even compete - on paper!
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