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360 renovating/tuning |
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shushqa
AMC Fan Joined: Jun/02/2017 Location: Sweden Status: Offline Points: 15 |
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Posted: Mar/26/2023 at 5:51pm |
Hello!
A few years back I wrote here to get some advices for my Javelin -74. Now I’m back to bring a few questions since I plan to make HP/torq next winter. Only mods so far I’ve done is new camkit(springs, lifters, shaft and rods) 10100703LK RPM airgap edelbrock Edelbrock 750 cfm (1407?) And prepped converter, with renovated 727 After some reading I’ve been looking at boring/stroking. How hard/expensiv would storke with std. 360 shaft be, Compared to 390/401 or even K1? Also heads: Read great stuff on eddys, indys and std dogleg. Wich is the to go to? I mean even if ported. And bore .045? Or what is recommended? Will talk to the builder more about what stuff he got to work with like ultrasound and so on. Anything i missed please tell med (Y) pistons, rods and all that i suppose depend on stroke and bore. Best regards Oscar! Keep ’em ramblin’ |
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1970390amx
AMC Addicted Joined: Jul/11/2008 Location: colorado Status: Offline Points: 3314 |
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The second page of this section has a write up on a 397 cubic inch build by sc397 you should read
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1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box |
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shushqa
AMC Fan Joined: Jun/02/2017 Location: Sweden Status: Offline Points: 15 |
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Ye been reading it, also got me reading on offset stroking(is that something ang enginerenovater would have all the knowledge for, or do I need data on AMC cranks?)
Also how far can i push de the build before a forged crank is needed to consider? He told me atleast not till 400hp. But like could i stretch it till 500-600 w/o problem or is 400 reasonable?
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5799 |
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You don’t seem to hear of people breaking 360 cranks, so they will take a fair bit of power.
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I've finally given up drinking for good...........now I only drink for evil.
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shushqa
AMC Fan Joined: Jun/02/2017 Location: Sweden Status: Offline Points: 15 |
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Okay, so unless I get a bargain on a 390/401 crank, offset and stroke the stock and go for 4.125 would be a good ”base”.
How about the heads? Heard indy’s is more of an ”race-only” choice. So ported eddys or porting my original doglegs?? Best regards, Oscar
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White70JavelinSST
Supporter of TheAMCForum Joined: Aug/08/2012 Location: Minnesota Status: Offline Points: 4866 |
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Max boring the block is asking for heating problems in a street engine. Keep the bore to the least that is possible and still have good cylinder walls. That is unless you can find a replacement or service block with extra thick walls. Those blocks do not have the displacement cast into the side by the motor mount bosses. Indy heads can be problematic due to casting issues, porosity and other troubles. Edelbrock heads are much better out of the box. Kevin Fontenont is in the process of making some new aluminum heads for AMC. See his post on Facebook. Original 291C heads are darn good heads as long as someone didn't crack the heck out of them. There's another later model cast iron head that works well also, can't recall the part number. Maybe someone will add that. Check for cracks in those heads too. Don't forget that AMC V8 engines are NOT neutral balanced. Everything from the vibration damper back to and including the flywheel/flexplate need to be balanced together. Good luck.
Edited by White70JavelinSST - Mar/27/2023 at 4:28pm |
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70 Javelin SST, second owner, purchased 1972
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shushqa
AMC Fan Joined: Jun/02/2017 Location: Sweden Status: Offline Points: 15 |
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Thanks! About the bore I guess I’ll have to get back to pistons later on. Read around abit and got tipped that along with .045 you’d be able to find a broader variety of pistons(might have mixed it up).
Won’t be doing anything untill the end of summer except for researching. While I’d love to pick it all apart and learn all the mechanism of the engine, I’m going to leave that job for a professional who’s got the tools. Though I’d love to have some idea of what the outcome will be! tldr/ Preparing a “wishlist” for the mechanic. ^^’ Thanks again! :)
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5799 |
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What realistically are you going to do with this engine and what fuel will you run, that will dictate some things. What gears are you going to run and what stall is the convertor?
Seems you have the basics for nice performance engine. With the 360, you generally need to add some compression, how much will depend on what fuel you are prepared to run. Your best option for an off the shelf forged piston is Wiseco, they come on 0.020" and 0.045" oversize, I would always run the smallest oversize you can, you won't see much difference between these two. For rods, there are a few options for a stock replacement forged rod, Molnar, K1. Remember that if you are doing a stroker combination, you will generally need some custom pistons, you can't just increase the stroke and run stock pistons and rods. For heads, I think if you can do your own porting, the factory iron heads are a good option otherwise they will probably end up costing you more that a set of Edelbrock heads. The Edelbrock heads are a nice performance upgrade, think of them as equivalent to a set of ported factory heads with all new hardware, of course you can improve them too with porting and other upgrades. Indy heads will be more of a race application, they do make 2 heads, one which is basically a performance replacement factory head and the other is a race head that will need more to make the work, like custom headers. Kevin's heads, saw them, they will be for a serious race motor and will need a lot of other stuff to make them work, I'm going to guess 700+ horsepower applications. Don't forget you have other options to make power, a little N2O if it's just for a blast down the strip, you can add a centrifugal supercharger (Torqstorm) or a turbo, maybe two. 400 HP is a good number for a street car and you can get there with fairly basic upgrades and not a lot of money. I'm a big fan of the old 343 flat top pistons into a 360 combo, which will get you somewhere around 10.0 - 10.5:1 compression with the larger chamber factory heads and half a point more with Edelbrock heads and all you need to do is run premium pump gas. |
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I've finally given up drinking for good...........now I only drink for evil.
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shushqa
AMC Fan Joined: Jun/02/2017 Location: Sweden Status: Offline Points: 15 |
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Fuel of the pump option around here(Sweden)
95octane(belive it’s called E10 nowadays due to environmental mixture) 98 octane and e85 It’s not the daily driver but still want to be able to go to a car meet as well as doing some runs down the 1/4. When I had the 727 fixed they send the converter asking for a stall around the recommended(Lunati) 2200-2400 rpm. The rearend will see some changes aswell(3.15 at the moment). Have had a blower dream for about 8years, not sure if it will ever come true ^^’ but at least getting the flow up and compression for now. (Have promised myself not ti remove the headers again until I work the heads,pistons and cylinders since it’s been a nightmare to keep ‘em from leaking..) |
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BassBoat
AMC Addicted Joined: Aug/29/2008 Status: Offline Points: 1719 |
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That cam would really be better matched to an engine with 10 to one compression via Wiseco flat top pistons. I have a couple 360s under construction with that cam. To add to what was said above, power comes from the heads. A 360 with good heads will make more power than a 397 or 401 with stock heads. Spend your money on good heads. Read some of jcisworthy's stuff on this forum.
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