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401 street strip build |
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Juan Montoya
AMC Fan Joined: Jul/19/2018 Location: Cape Coral FL Status: Offline Points: 1 |
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Posted: Jul/19/2018 at 11:08pm |
Hi I just registered my question is I'm thinking to buy a 1981 amc spirit,it's a 6 on line with stick shift can I install a 304 with the same gear box ( transmit) I really don't know to much about motors and transmissions set ups can someone give advice
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mixed up
AMC Addicted Joined: Jun/16/2015 Location: Monroe mich Status: Offline Points: 2177 |
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the howard cam looks good I run a 540 lift solid in my 290 with a torqer intake it give good power in the whole rpm range and as far as solid cams I run the shur lock nuts and very seldom have to readjust the rockers so I would not be afraid of a solid cam good luck on the build sounds like your heading in the right direction for fun
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69 amx 290 auto
65 220 290 4spd 80 ford fairmont |
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amx73
AMC Nut Joined: Aug/28/2009 Location: NJ Status: Offline Points: 294 |
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I asked Eric at Howard's cams, "why such a big cam" and he basically told me what jpnjim said. The lobes aren't aggressive so it's easier on the valve train. And with 4.10's and a good converter, and the 112LSA it would be fine. Soooo, I ordered it from Jegs to put in my 73' 401!!! It's very similar to the one I'm going to build.only differences are Its got Edelbrock heads, and 10.5:1 .020 over Ross pistons. Oh, and FI Tech fuel injection, and a five speed manual trans. It's currently apart for a "freshen up" and I've been wanting to see what a better cam would do. I'm currently running a Comp 280H grind. The Intake is an RPM Air Gap because it's mostly street driven.
Edited by amx73 - Jul/19/2018 at 7:34pm |
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Red means run son, numbers add up to nothin'!
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PHAT69AMX
AMC Addicted Joined: Jul/07/2007 Location: West Virginia Status: Offline Points: 5919 |
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Agree, I should have used a solid lifter flat tappet cam in my last build...
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Red Devil
AMC Addicted Joined: Jul/10/2007 Location: Canada Status: Offline Points: 1743 |
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If you don't mind setting lash and checking periodically, a solid cam is likely a better option than a big hydraulic. For a comparable rpm range, typically less seat timing, more @0.50", @0.200" duration, more lift, more stable at higher rpms ... and no lifter start-up rattle and a bit easier on the starter for a seldom-driven car.
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6PakBee
Supporter of TheAMCForum Charter Member Joined: Jul/01/2007 Location: North Dakota Status: Offline Points: 5457 |
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Boy, do I identify with that!!
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Roger Gazur
1969 'B' Scheme SC/Rambler 1970 RWB 4-spd Machine 1970 Sonic Silver auto AMX All project cars. Forum Cockroach |
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jpnjim
AMC Addicted Joined: Nov/25/2007 Location: New England Status: Offline Points: 2752 |
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One more thing, I'd be leaning away from the Performer RPM with any of the bigger cams we're talking about. I don't claim to be an intake expert either but the RPM seems to trade mid range for top end compared to a Torker. No sense going with the bigger cam if the Performer RPM will be the limiting factor when you get to where the cam really starts working. |
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71 P-code 4spd Javelin/AMX
some Jeeps and some Fords |
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jpnjim
AMC Addicted Joined: Nov/25/2007 Location: New England Status: Offline Points: 2752 |
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I like Howards Cams, it took about a week to get a custom AMC cam from them a couple months ago, I ordered it through Competition Products, they are in the same building as Howards and had the best prices: I'm not a cam expert, I just overthink things that I think I understand until they either start to make sense to me or I really screw them up From your description, I think these are the lobes he's recommending: 1hf235325 Duration 289@.006" 262@.020" 235@.050" 147@.200" Lift .325" lobe .520" w/1.6 rockers 1hf243338 Duration 297@.006" 270@.020" 243@.050" 156@.200" Lift .338" lobe .543" w/1.6 rockers Lobe list is here: these lobes are on page one and two "standard ramp hydraulic flat tappet" This is a pretty healthy cam, obviously bigger than the cam from the Car Craft build. with 4.10's and a decent converter he probably figured you could handle it. A few things I'd point out: 1)you have to make sure the heads are set up for over .500" lift 2)289/297 gross duration on a 112 lobe center is going to have a fairly late intake closing, which will lower your dynamic compression ratio quite a bit from the Lunati cam you first mentioned, not that it's a bad thing on pump gas, but it might be happier with 10:1 compression 3)This is what most people would call a "Chevy Grind", meaning the lift to duration is optimized for the smaller diameter Chevy lifter, not a bad thing, it tends to be easier on the valve parts than a lobe designed for our wider lifters. The faster acting cams optimized for wider .903/.904 lifters are on page 25 of the Lobe List above. What usually ends up happening (if you choose a .903/.904 cam instead) is you can pick a cam with less .050" duration, much less .006" and .020" duration, but more lift and more .200" duration. The cam can act more mild, because it isn't open as long, but because it opens and closes at such a steeper rate, it actually allows more flow in that shorter time period. Compare: HM2303541A Duration 277@.006" 254@.020" 230@.050" 150@.200" Lift .354" lobe .567" w/1.6 rockers to the 1hf235325 Duration 289@.006" 262@.020" 235@.050" 147@.200" Lift .325" lobe .520" w/1.6 rockers Much less gross duration 277 vs 289, 8 degrees less at .020", 5 degrees less at .050", but then 3 degrees more at .200, that's the "under the curve" lift people talk about. A side effect of the .904 grinds is you end up with more lift even in a smaller cam, which you'd want your head to be able to handle, and hopefully be worked to flow well at these lifts, but on the positive you may end up with an engine that idles better, pulls better at a lower RPM, and makes more power on top. (in a perfect world). The added stress on your valvetrain and added potential to wipe out the more aggressive lobes should be taken into account too, which may be why they went with a standard grind for your recommendation. Page 4 of that lobe list has "Aggressive Hydraulic Flat Tappet" lobes that are part way between the standard type grinds that were recommended, and the .903/.904's. Page 26 has Ford .875 lobes that can be slightly tamer than the .903/.904 grinds, but not always. I hope my advice didn't just muddy the waters too much, and if I'm in error in any of this I'd invite anyone to clear things up for me. Edited by jpnjim - Jul/19/2018 at 3:45pm |
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71 P-code 4spd Javelin/AMX
some Jeeps and some Fords |
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PHAT69AMX
AMC Addicted Joined: Jul/07/2007 Location: West Virginia Status: Offline Points: 5919 |
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Those specs look a lot like an Elgin E-981-P AMC Camshaft...
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5799 |
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That sounds better, the XE262H seemed a bit small to me.
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