Adding a little more muscle to original 290

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Any suggestions on what cam to use to make the original 290 a little more powerful without going to alot of expense and trouble. It still has the original 2V carb. which was rebuilt when I was getting the tranny rebuilt. It also has the stock single exhaust that I will most likely replace to dual at some point, and possibly 4v carb in the future. Thanks

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RebelYell Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: May/04/2011 Location: North Carolina Status: Offline Points: 480	Post Options Post Reply Quote RebelYell Report Post Thanks(0) Quote Reply Topic: Adding a little more muscle to original 290 Posted: Feb/11/2012 at 3:13pm
	Any suggestions on what cam to use to make the original 290 a little more powerful without going to alot of expense and trouble. It still has the original 2V carb. which was rebuilt when I was getting the tranny rebuilt. It also has the stock single exhaust that I will most likely replace to dual at some point, and possibly 4v carb in the future. Thanks


farna Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: United States Status: Offline Points: 7132	Post Options Post Reply Quote farna Report Post Thanks(0) Quote Reply Posted: Feb/11/2012 at 4:13pm
	The Edelbrock Performer package is probably the best way to go for a mild street engine. You can get the cam and lifters now, change the intake and carb later. The cam should work fine with the 2V.
	Frank Swygert American Motors Cars Magazine www.amc-mag.com

Buzzman72 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Sep/15/2009 Location: Southern IN Status: Offline Points: 464	Post Options Post Reply Quote Buzzman72 Report Post Thanks(0) Quote Reply Posted: Feb/11/2012 at 5:07pm
	Just waiting for the folks to jump in and tell you to yank that "boat anchor" and drop a bigger engine in its place...3.....2.....1....
	Buzzman72...void where prohibited, your mileage may vary, objects in mirror may be closer than they appear, and alcohol may intensify any side effects.

RebelYell Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: May/04/2011 Location: North Carolina Status: Offline Points: 480	Post Options Post Reply Quote RebelYell Report Post Thanks(0) Quote Reply Posted: Feb/11/2012 at 5:36pm
	Being that both cars I have are original, and will require money to be spent on needs, as they present themself, I'm reluctant to spend money on wants until they are necessary. I know that I should just be happy with what I have, but that's not always so easy. Once you start making one change it seems to be necessary to make another, and another, and another.


fast401 Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List AMC Addicted Joined: Sep/16/2008 Location: swanton, ohio Status: Offline Points: 2188	Post Options Post Reply Quote fast401 Report Post Thanks(0) Quote Reply Posted: Feb/11/2012 at 8:47pm
	Maybe open the exhaust to 2.5 and they do make quiet good flowing muffler if you want it to look stock. Also go to a K&N air filter to fit your stock pan. The 290 wasn't no sloutch especially in the AMX. Also I have seen 2 barrels that were rejetted for more performance.
	Disturbing the peace since 1970!!! AMX 19245 www.fast-401.4t.com

wantajav Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Sep/04/2009 Location: PA Status: Offline Points: 537	Post Options Post Reply Quote wantajav Report Post Thanks(0) Quote Reply Posted: Feb/11/2012 at 9:05pm
	Hey Rebel: Me too on the 290. Funny in a way because I spent lots of time grab a 360 and a 343 both rebuilders in pieces but for now: wondering what I can do with what is in the car now, a 290 2V. In my mind : define little expense. Seems like a cam is the single thing you can do to make these engines more powerful that plus a small dry nitrous kit. Keep in mind the engine is ~ 50 years old and the pistons are cast aluminum. I have heard of the aluminum intakes etc...but someone also told me a bigger 2 bbl = 500 cfm is a big bang-for-the buck....FYI I think 2bbl and 4 bbl are measured at different vacuums so 500 cfm 2bbl does not equal 500 cfm 4 bbl --- may want to double check this. The pertronix points-free kit may not add a ton of HP but the car will run smoother. What tranny are you running we probably got a tight torque convertor = slow off the line. Finally I'm looking into some 304 heads heard they were way better than the 290's then again a cam/nitrous should overcompensate for the minor differences. DEPENDS ON HOW MUCH HP YOU NEED. A true 250 hp in a light car with good traction is a tough contender, I've had four 5.0 Mustangs they were plenty street strong and none made the big numbers. Good luck would love to hear updates Mike

1970390amx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jul/12/2008 Location: colorado Status: Offline Points: 1255	Post Options Post Reply Quote 1970390amx Report Post Thanks(0) Quote Reply Posted: Feb/11/2012 at 10:36pm
	Make sure your engine is in good shape. I would do a compression test an a leakdown test to make sure the base engine is in good shape. You can check timing chain stretch by grabbing the crank pulley and rotating it back an forth, you will feel the play as you turn it back and forth and you start turning the valve train. The more it is stretched the more it will retard cam timing. Retarded cam timing will hurt upper mid range and upper rpm power. You will have to decide if its loose enough to change. You said the carb was just rebuilt so I would leave it alone for now although some jetting changes may help hp. Ignition is by far the most under looked hp gain. A points type distributor almost always is worn severely at the upper bushing, this makes it impossible to set dwell. A petronix conversion in a good distributor is a good place to start, to will not make a lot of power but points wear, and this changes dwell and timing. There is lots of info on the web for timing and advance mods on a delco distributor. I have had the best luck not using the vacuum advance with 10-14 degrees initial advance with 34-38 degrees total advance. A 2'' duel exhaust is more than big enough for a 290. The factory designed a good all around package unless you are going to change alot making sure everything is tuned its best will make more power than anything. My opinion, yours and others may differ.
	1970 390 4speed Bittersweet shadow mask AMX 1970 Amx missing most everything, or in a box

17tamx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Dec/23/2008 Location: Peoria, AZ Status: Offline Points: 1123	Post Options Post Reply Quote 17tamx Report Post Thanks(0) Quote Reply Posted: Feb/12/2012 at 2:07am
	290 2 bbl with single exhaust. Biggest bang for the buck IMO. Install the 4 bbl carb and intake now, skip the cam for now and add the dual exhaust as soon as you can. Leave the stock exhaust manifolds for now. Have the distributor curved before you add the petronix ignition. It will be a fun motor.
	Kirk P. Fletcher 70 AMX BBG w/Shadow 390 4sp 71 SC360 Wild Plum Ram Air 4sp 67 Rogue Convert 343 4sp 66 Rogue Hardtop 290 Auto 66 440 Convert 232 Auto

RebelYell Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: May/04/2011 Location: North Carolina Status: Offline Points: 480	Post Options Post Reply Quote RebelYell Report Post Thanks(0) Quote Reply Posted: Feb/12/2012 at 8:52am
	Thanks Frank, I hope to see you at the Autofair. I appreciate all the input, and I'll most likely end up following the suggestions. The car has the BW M40 transmission. Not sure of the gear because the tag is not there, and I haven't pulled the plate. Like my old 70 Javelin, it sucks gas. That would be okay if I felt the urge to smile when I stepped on the gas pedal. I'll just be patient. When I come accross a good deal on something I'll pick it up. Edited by RebelYell - Feb/12/2012 at 9:34am


farna Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: United States Status: Offline Points: 7132	Post Options Post Reply Quote farna Report Post Thanks(0) Quote Reply Posted: Feb/12/2012 at 11:48am
	I have to agree with wantajav - EASIEST and cheapest thing to do is change the intake and carb for now. The 600 4V will probably improve mileage over the 2V and give a little torque increase. This is due to the smaller primary venturii over the larger 2V. There's the catch though -- open up the secondaries and you doubl;e the venturi opening and drop charge velocity, which will momentarily decrease torque until the rpm comes up to need the added size. That's the main reason you have a short lag when a 4V is suddenly opened. That's why you want a vacuum secondary for the street -- it doesn't open real fast and you don't get a big lag. On a race motor the cam/intake/carb (well, the whole engine!) can be matched/tuned to reduce or even eliminate that lag. A cam change will make as much or more difference as the intake and carb change though. If you can afford to do both, do it! You have to take the intake off to change the cam, so you're a bit ahead to do both at the same time. If you can't afford both, just choose. I think the cam change would make the most noticeable difference, it usually does since AMC was pretty conservative with their stock cams. Takes a bit more work. If it will be around a year before you can get to the intake and carb there won't be much loss in waiting to do that... just the cost of the intake gaskets. I've done things like this before due to limited funds. Sometimes it just can't be helped! Getting a little pleasure/benefit for now is just sometimes worth a bit of extra cost down the road. I know you get a bit of sound change from dual exhausts, but not much bang for the buck as far as performance. A 2.5" single exhaust has plenty flow for a warmed over 290. It's cheaper than dual 1.75" or 2". Only one muffler to buy, less pipe. An easy way to get the look and some of the sound is to use a 2.5" into the muffler then split into 1.75" or 2" dual pipes after the muffler. Or get a GM F body muffler that has one inlet and two outlets. A real big exhaust on a street engine can cost you low speed/cruising speed torque. You have to consider how often you really want/need a lot of flow. For a street engine that's rare. Drag car -- you need it for the high rpm power. For true duals on a 290 1.5" pipes would be a good compromise as far as low/mid rpm torque vs. WOT flow. Racing is totally different -- bigger is better, but you plan on going from fast idle to WOT in an instant. Road racers don't need the absolute biggest exhaust either. Good torque pulling out of the curves wins more road races than the drag race down the straights.
	Frank Swygert American Motors Cars Magazine www.amc-mag.com