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401 Build For My Rock Crawler

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SirDigger View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SirDigger Quote  Post ReplyReply Direct Link To This Post Posted: Aug/09/2017 at 9:08am
Get an Deep Sump Oil-Pan...

And as others menstions, get an Standalone EFI...


SirDigger&his german Friends are looking for Parts http://theamcforum.com/forum/the-german-amc-forum-ambassadorsirdigger-needs_topic83570.html
1970 Javelin SST 304
1970 Javelin SST 360
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jpnjim Quote  Post ReplyReply Direct Link To This Post Posted: Aug/15/2017 at 5:51am
I'd run a compression test on it before cracking it open (if you haven't yet),
would help to judge ring seal and if you ought to quickie-hone and ring it while you are there.

I'd also take a peek at the bearings,
AMC engines were designed for tight bearing clearances, pressure suffers as the bearing shells wear out.

AMC rule of thumb is keep the lift under .500 and the stock valve train is happy,
for what you're trying to do I would go with nice gentle ramps in whatever cam I chose.

The .904 lifters can take an aggressive fast acting cam,
but in a rock crawler there's not much benefit to doing it, no sense opening yourself up to the possible wear issues that go along with that.

What transmission are you using?

Also
400-450 hp might be unrealistic depending on the RPM you are building for.

Hp = Torque at 5252 RPM

So 400 HP = 400 Tq @5252 RPM

As you lower the RPM you make max torque at, you lower the resulting HP.

500 Tq at 4000rpm = 380 hp
600 Tq at 3000rpm = 343 hp
700 Tq at 2000rpm = 266 hp

^these numbers are all pretty unrealistic for a junkyard engine,
and still don't give 400-450hp.

Horsepower needs RPM,
If you're not building an RPM engine, I wouldn't worry about where the HP ends up.

I think the engine will do everything you want it to otherwise though Smile
71 P-code 4spd Javelin/AMX
some Jeeps and some Fords
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jeep_Guy Quote  Post ReplyReply Direct Link To This Post Posted: Aug/16/2017 at 3:54pm
Thanks for all the info. i did some more research and made some decisions. so here is where i am at. i compression tested the 401 and my lowest hole was 125 and the highest was 140 so seams to be sealed up pretty good. i got the motor out last night and on the stand. i will be running a TH400 behind the 401 with a stick ish converter and rebuild.  i have also ordered all my part to freshen up the 401 here is the list:

summit 8600 cam and lifters
comp cam springs
valve seals
machined valve locks 
double roller timing set
melling oil pump kit
billet HEI
edelbrock dual plane intake
set of headers
and a rebuild for the 650 holley
gasket set

i also did alot of research on the oiling mods and decided to do the mod where you drill and tap the timing cover at the dist gear and install a copper oil line Tee'd off the oil pump gauge port to aid in dist. gear and timing set oiling. also saw a video of a guy who "ported" the timing chain cover to improve flow. Is that a worth while mod? anyone see anything i have missed?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote shootist Quote  Post ReplyReply Direct Link To This Post Posted: Aug/18/2017 at 10:48am
If you are not going high RPM you really don't need any oiling mods. I would however take extra care on the timing gear install by ensuring that the distributor drive gears oil paths are open and in alignment. You can search that for picture but basically the cam should be checked to ensure the front race and bearing is used. There are two types, one were the oil channel is in the bearing and the other the oil channel is cut into the cam. The top timing chain gear from some places have had flashing blocking the dizzy gear oil feed hole and/or had the oil feed groove not cut all the way through the sprocket. Those are probably the most common causes for failure and why most people see so many threads about it. I was personally bitten by the bad timing cover where it was drilled incorrectly and caused the gear mesh on the distributor to be off and thereby destroy distributor and cam gears. To each their own of course but I feel the external dizzy line added is not needed should you take the previously mentioned steps. Of course matched gears are also required. I run the MSD iron gear set in my motor since I chewed the stock ones with a bad timing cover. Have had no issue since swapping the cover with a known good bulltear one. I also would recommend bulltear's HRC oil pump gears. I think the relief groove they cut into them also really helps reduce the potential for dizzy gear failure.
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