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Hot street 343 build

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Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: https://theamcforum.com/forum/forum_posts.asp?TID=94581
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Topic: Hot street 343 build
Posted By: pipefactory
Subject: Hot street 343 build
Date Posted: Jun/06/2018 at 6:49am
I decided my 562 hp 401 in my rambler was too much for the street.
It has a 4 speed with 410 gear now and is fun to drive but would be better with less motor.
I have a low mile standard bore standard crank 343 I'm building.
I have new badger flat tops that will end up .010 in the hole after decking and squaring the block.
Already have the milodon timing drive all mocked up as well as timing cover.
I'm going with a solid crane with 238 248 dur. .512 .533 lift 112 lisa
I'm swiping the sr401 heads that flow 333 at 700 of my 401
torker intake and my e85 carb
Should end up 11.52 and run e85.
Any input?

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Face distorting torque
10.99@121 mph



Replies:
Posted By: WesternRed
Date Posted: Jun/06/2018 at 7:06am
Sounds like a pretty stout 343, would like to see what it makes when done.


Posted By: pipefactory
Date Posted: Jun/06/2018 at 7:17am
These are the original pistons.
Sorry about the crappy aluminum welding, I got a new high tech welder and didn't read the instructions. I'm used to my giant old Miller.



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Face distorting torque
10.99@121 mph


Posted By: 1982AMCConcord
Date Posted: Jun/07/2018 at 9:01am
Originally posted by pipefactory pipefactory wrote:

I decided my 562 hp 401 in my rambler was too much for the street.
It has a 4 speed with 410 gear now and is fun to drive but would be better with less motor.
I have a low mile standard bore standard crank 343 I'm building.
I have new badger flat tops that will end up .010 in the hole after decking and squaring the block.
Already have the milodon timing drive all mocked up as well as timing cover.
I'm going with a solid crane with 238 248 dur. .512 .533 lift 112 lisa
I'm swiping the sr401 heads that flow 333 at 700 of my 401
torker intake and my e85 carb
Should end up 11.52 and run e85.
Any input?

Have you considered using the 304/360 crankshaft to stroke it out a little? There's a lot of those around here... and it seems like a good build. A couple of guys running that crank/block combo are pulling some really impressive numbers in the dyno too. Its a unique build and its been done with a high degree of success.



Posted By: pipefactory
Date Posted: Jun/07/2018 at 10:34am
Originally posted by 1982AMCConcord 1982AMCConcord wrote:

Originally posted by pipefactory pipefactory wrote:

I decided my 562 hp 401 in my rambler was too much for the street.
It has a 4 speed with 410 gear now and is fun to drive but would be better with less motor.
I have a low mile standard bore standard crank 343 I'm building.
I have new badger flat tops that will end up .010 in the hole after decking and squaring the block.
Already have the milodon timing drive all mocked up as well as timing cover.
I'm going with a solid crane with 238 248 dur. .512 .533 lift 112 lisa
I'm swiping the sr401 heads that flow 333 at 700 of my 401
torker intake and my e85 carb
Should end up 11.52 and run e85.
Any input?

Have you considered using the 304/360 crankshaft to stroke it out a little? There's a lot of those around here... and it seems like a good build. A couple of guys running that crank/block combo are pulling some really impressive numbers in the dyno too. Its a unique build and its been done with a high degree of success.

I've put flat top 343 pistons in 360's in the past. I've just never built a straight up 343 yet. 
The crank is an Arm-asteel , don't know if that means anything but it is standard and will just need a polishing.
I also have Doug 1 3/4" long tube headers and an E84 carb I built with a 750 Proform body.
It should be fun with a 4 speed, 4.10 gears in my 2900LBS Rambler Classic.


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Face distorting torque
10.99@121 mph


Posted By: 1982AMCConcord
Date Posted: Jun/07/2018 at 12:22pm
The ArmaSteel 290/343 crank is nothing really special. ArmaSteel was just the name of the General Motors foundry where it was cast. AMC used that foundry early on but technically... the metal from the later 304/360 crank is actually supposed to be better than the earlier ArmaSteel.

Anyway... Since you are using a 4 speed I guess there is no real point in swapping to a longer stroke and spending extra to modify the later model 304/360 crank flange for an earlier manual trans but the possibility is there because all of AMC crankshaft are swap-able between the various AMC V8 blocks.  

http://www.hotrod.com/articles/can-you-stroke-an-amc-290-v8/

It does sound like you will have a pretty potent set up regardless.. I just thought I mention the 304/360 crank swap because in several cases its helped a few guys make a real screamer out of their 343's.


Posted By: 343sharpstick
Date Posted: Jun/13/2018 at 9:50am
I'll be watching this one closely. My Javelin Came with a 343 and I used it stock for about 5 years. Very happy with it
My Javelin currently has a slightly modified 401.
At some point the 401 may go into a different car, and original 343 back into the Javelin. If/When I do that I'd like to go through the motor and do something similar to this.


Posted By: jcisworthy
Date Posted: Jun/13/2018 at 11:27am
I built a 343 for a customer a couple years ago. 10.3 compression, flat tappet custom ground Bullet cam, ported iron heads with an air gap intake. 455 hp 446 tq




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Specializing in dyno services, engine building, and cylinder head porting

rbjracing.com
Phone Number 518-915-3203


Posted By: PHAT69AMX
Date Posted: Jun/13/2018 at 11:27am
Short 3.28 stroke of the 290 - 343 ought to wind up like something fierce...
Gonna drill extra holes in the lifter valley for improved drainback ?
Work the front Main Cap and Timing Cover ? 


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Link to a http://www.youtube.com/watch?v=MySiKQsmWxU" rel="nofollow - Short YouTube Burnout Video



Posted By: Red Devil
Date Posted: Jun/13/2018 at 11:35am
Originally posted by PHAT69AMX PHAT69AMX wrote:

Gonna drill extra holes in the lifter valley for improved drainback? Work the front Main Cap and Timing Cover?

Often wondered if drilling holes in the valley and dumping oil onto a spinning cam, crank and rods would make it worse for oil to get back to the sump ... and maybe even toss more oil mist from below up top? Really need a low-pressure to draw oil back to the sump or rely on surface tension and gravity to drain.


Posted By: SC397
Date Posted: Jun/13/2018 at 11:49am
Originally posted by Red Devil Red Devil wrote:

Originally posted by PHAT69AMX PHAT69AMX wrote:

Gonna drill extra holes in the lifter valley for improved drainback? Work the front Main Cap and Timing Cover?

Often wondered if drilling holes in the valley and dumping oil onto a spinning cam, crank and rods would make it worse for oil to get back to the sump ... and maybe even toss more oil mist from below up top? Really need a low-pressure to draw oil back to the sump or rely on surface tension and gravity to drain.


That's a good question. In my opinion, I would rather direct the oil to a cam lobe than have it pool up.
https://flic.kr/p/Goi8D8" rel="nofollow"> https://flic.kr/p/Goi8D8" rel="nofollow - 017 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr
Learned this one from Mr. Landis. I drill the 2 holes in the very back to 5/16" and smooth out a channel to make it a little easier for the oil to flow.
https://flic.kr/p/24RXq1Y" rel="nofollow"> https://flic.kr/p/24RXq1Y" rel="nofollow - IMG_4319 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr


Posted By: WesternRed
Date Posted: Jun/13/2018 at 5:20pm
Looking at it, it seems that the drilled holes would direct oil away from the am rather than onto it. All I did with mine was clean up the casting flash on the existing drain back holes, not that there is likelt be any restriction there. Is there any benefit of drilling out the oil return holes in the heads to a larger size?

Would there be any benefit in running a longer rod and a dished piston to achieve some quench in a 343? It seems you have that covered by decking the block and retaining the flat tops anyway.


Posted By: PHAT69AMX
Date Posted: Jun/13/2018 at 6:10pm
The heads drain to the Lifter Valley, there has got to be a lot of oil that collects in the valley at rpm
and in the heads before it drains to the valley.  Long time ago Bulltear Matt posted what size
the head drain back holes could be enlarged to, fail to remember to what size...
I lack real world hands-on, but it just seems with high rpm drainback becomes an "issue"...
How many times have you made a mess pouring old oil too fast into a funnel into a jug ?
In the Projects Section, the dude with the awesome vintage SCCA BP car,
has the Drain Back Lines that go from Valve Covers to the Pan like in the PAS book.
In the old AMC TransAm video, when Penske & Mark D. first started with AMC Oil was a problem
which once they figured out they did much better, wonder if it involved Drainback?
It makes sense, AMC's Oil Pump outlet feeds the Lifter Galleys first, a bunch of oil
has to end up on the heads and in the valley faster than it can drain back to the pan... at high rpm anyways...
All 16 Lifters in their bores are potential "oil leaks" like loose main / rod bearings...
Lifter Bores are seldom bushed, new replacement lifter diameters maybe "compromised" to Mopar size...
Not like I "know", but I can just see how, thinking about it...
Chevs oiling from the bottom feeding the crank first if it's loose / leaks, less of an issue...
And the 3.28 Stroke 290-343 Crank is gonna just beg to be rev'd...
And agree, would look at reducing the stock .060 Deck Clearance for better Quench...
Then open up the Head Combustion Chambers to unshroud the valves to keep CR reasonable... 


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Link to a http://www.youtube.com/watch?v=MySiKQsmWxU" rel="nofollow - Short YouTube Burnout Video



Posted By: Boris Badanov
Date Posted: Jun/13/2018 at 6:47pm
Getting that oil past everything that rotates is the best solution.

You can EASILY store a few quarts in the valve covers and the back of the lifter gallery
under hard acceleration and at high rpm.

IMO if you have a roller cam you do not want or need any oil on the cam and crank from above.


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Gremlin Dreams


Posted By: Trader
Date Posted: Jun/14/2018 at 6:01am
Everything is like a pendulum, swings one extreme and back. I like removing all flashings, internal and external, just seems prudent to remove the little pieces that may come loose or start the beginings of a crack.
But here is an old post that goes to the extreme end:
http://theamcforum.com/forum/weird-oiling-modification_topic29999_page1.html?KW=valley+holes" rel="nofollow - http://theamcforum.com/forum/weird-oiling-modification_topic29999_page1.html?KW=valley+holes


Posted By: jpnjim
Date Posted: Jun/14/2018 at 8:14am
Originally posted by Trader Trader wrote:

Everything is like a pendulum, swings one extreme and back. I like removing all flashings, internal and external, just seems prudent to remove the little pieces that may come loose or start the beginings of a crack.
But here is an old post that goes to the extreme end:
http://theamcforum.com/forum/weird-oiling-modification_topic29999_page1.html?KW=valley+holes" rel="nofollow - http://theamcforum.com/forum/weird-oiling-modification_topic29999_page1.html?KW=valley+holes

Wow that's one way to "fix" things!

Just goes to show,
you never really know what the last guy did until you pull it all apart ConfusedConfusedConfused


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71 P-code 4spd Javelin/AMX
some Jeeps and some Fords


Posted By: Boris Badanov
Date Posted: Jun/14/2018 at 11:24am
That seems like a bad idea to me.

IMO Keeping oil OFF the rotating assembly is best.




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Gremlin Dreams


Posted By: gremlinsteve
Date Posted: Jun/14/2018 at 11:56am
I agree
Keep oil off the rotating assembly
They make hi performance coatings that help do that


Posted By: 67 Marlin
Date Posted: Dec/22/2018 at 9:29pm
Any update on this sweet-sounding 343 build?


Posted By: pipefactory
Date Posted: Dec/25/2018 at 8:01pm
On hold at this time.
I'm on the hunt for a 71-72 javelin as a driver then put the 343 in it


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Face distorting torque
10.99@121 mph


Posted By: pipefactory
Date Posted: Feb/11/2020 at 6:27am
343 block just went to the machine shop for deck square -.020
I got my 71 javelin has a 304 and the 343 is going in it.
Changed a few details
6" 5143 Procomp rods, 
Keith Black 4.080 claimer pistons
Dish, with two valve reliefs
Hypereutectic aluminum
1.433 Compression Height
+18.00 Piston Head Volume cc

360 crank .010 on the mains .015 rods
I have a nice Sig Erson cam I'm going to check specs with my degree wheel but it has a .474 lift
I using late heads with 5/16" outer exhaust bolts



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Face distorting torque
10.99@121 mph


Posted By: Sonic Silver
Date Posted: Feb/11/2020 at 9:33am
Originally posted by pipefactory pipefactory wrote:

343 block just went to the machine shop for deck square -.020
I got my 71 javelin has a 304 and the 343 is going in it.
Changed a few details
6" 5143 Procomp rods, 
Keith Black 4.080 claimer pistons
<span style=": transparent; font-weight: bold; font-family: Arial, Trebuchet, sans-serif; font-size: 14.4px;">Dish, with two valve reliefs</span>
<span style=": transparent; font-weight: bold; font-family: Arial, Trebuchet, sans-serif; font-size: 14.4px;">Hypereutectic aluminum</span>
<span style=": transparent; text-align: right; font-family: Arial, Trebuchet, sans-serif; font-size: 14.4px; font-weight: bold;">1.433 </span><span style=": transparent; text-align: right; font-family: Arial, Trebuchet, sans-serif; font-size: 14.4px;">Compression Height</span>
<span style=": transparent; text-align: right; font-family: Arial, Trebuchet, sans-serif; font-size: 14.4px; font-weight: bold;">+18.00 </span><span style=": transparent; text-align: right; font-family: Arial, Trebuchet, sans-serif; font-size: 14.4px;">Piston Head Volume </span><span style=": transparent; text-align: right; font-family: Arial, Trebuchet, sans-serif; font-size: 14.4px; font-weight: bold;">cc</span>

360 crank .010 on the mains .015 rods
I have a nice Sig Erson cam I'm going to check specs with my degree wheel but it has a .474 lift
I using late heads with 5/16" outer exhaust bolts




I have an Erson catalog that is a few years old, and they list a Street Fighter hydraulic with 288 advertised duration, and 218 at .050 with .474 lift. It is on 112 lobe centers with 5 degrees ground in advance.
They have 2 others with .478 lift. One with 214 duration on 111, and one with 222 on 114.


Posted By: greendragon
Date Posted: Feb/29/2020 at 9:30am
I know this is a old post...but I have to ask...what was..’too much for the street mean?....just finished my own 560hp bullet cam build and very excited to feel the 560hp...just what was about it you didn’t like?

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moneypit


Posted By: pipefactory
Date Posted: Mar/01/2020 at 10:22am
My 63 Rambler is still fun to drive but it gets about 3 miles to the gallon and with the cam that's in it she really gets to bucking going down Tower Ave at 35 mph. I'm just leaving it in the trailer until I take it to the drag strip.
My 71 Javelin I bought is real cool but the 304 was not so its getting a 9.3 to 1 343 with later dog leg heads.

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Face distorting torque
10.99@121 mph


Posted By: pipefactory
Date Posted: Mar/01/2020 at 10:25am
Found the cam card, it's a little more than I wanted but going to try it.
.484" lift 234 @.050 108 LSA

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Face distorting torque
10.99@121 mph


Posted By: Trader
Date Posted: Mar/01/2020 at 10:46am
I;m assuming you have manual brakes? With that cam your going to be about 14" to 15" of vacuum and that is just under the 15+" that is usually recommended.
You could advance that cam more to get above the 15" vacuum but would have to be very careful on the intake valve clearance.
Advancing that cam would also give it better street manors. 


Posted By: Sonic Silver
Date Posted: Mar/01/2020 at 11:26am
Originally posted by Trader Trader wrote:

I;m assuming you have manual brakes? With that cam your going to be about 14" to 15" of vacuum and that is just under the 15+" that is usually recommended.
You could advance that cam more to get above the 15" vacuum but would have to be very careful on the intake valve clearance.
Advancing that cam would also give it better street manors. 
I don't see that cam having anywhere near that much vacuum.


Posted By: pipefactory
Date Posted: Mar/01/2020 at 2:16pm
Just manual. They are all rebuilt and have had to panic stop twice last summer and did just fine.

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Face distorting torque
10.99@121 mph


Posted By: pipefactory
Date Posted: Mar/01/2020 at 6:47pm
I weighed my new pistons and rods, 192 grams lighter than stock.
Also I have a nice Torker I welded up heat crossover and an Offenhauser 360 not sure which I'm gonna use.
I'm using Edlebrock shorty headers, I removed the small exit flanges and welded on 3" mandrel bent pipe I ran an 11.26 with these in my rambler.
650 Summit carb.
Internally balanced.
Later rocker bridge heads converted to screw in stud.
I port matched intakes and cleaned up the exhaust ports, polished up the pockets.
I tried not to change the shape as I don't have a flow bench.
You guys think it will make 350 hp



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Face distorting torque
10.99@121 mph


Posted By: purple72Gremlin
Date Posted: Mar/01/2020 at 7:28pm
Just me. I get it about performance.    But in my experience performance and gas mileage doesnt mix. If you want fuel economy  go buy a 4 cyl car.  I get 35 mpg on a Honda civic. 


Posted By: sweatlock
Date Posted: Mar/01/2020 at 7:47pm
It’s about balance - avoid extremes, in life and cars. A rumpity-rump car that bucks at speeds less than 35 MPH and gets 3 MPG while being loud as he!! gets really old, really quick. If you’re after sub-11’s in the quarter, okay. 

For a ‘street’ car (and I get there’s a difference of opinion in what that means), a good running/idling engine with crisp throttle response and low-end torque that pushes you back in your seat while you can still hear the radio is a wonderful thing and a joy to drive. 

However, like everything else in life, it’s extremely subjective. 


Posted By: pipefactory
Date Posted: Mar/02/2020 at 7:17am
Heres the heads and an oil pan I built



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Face distorting torque
10.99@121 mph


Posted By: pipefactory
Date Posted: Mar/22/2020 at 6:30pm
Finished flycutting the intake reliefs in my pistons tonight.
Dropping parts off to the balancer Wednesday.
Heads are finished, stainless valves 10 degree retainers and locks.
Pulled 16" vacuum.



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Face distorting torque
10.99@121 mph


Posted By: pipefactory
Date Posted: Sep/07/2020 at 7:51am
Well heres an update on my 343.
Its in a 71 Javelin, shorty headers, full quiet exhaust with 2" tail pipes, 2.87 gears and a trac loc and Cooper Cobra 60's.
I went to the drag strip with it. My freind bet me $20 bucks I can't make the 13's.
My 1st run was 13.87 and the fastest was 13.64 all from the little 343.
Mines on the left, Phil Hansons on the right.


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Face distorting torque
10.99@121 mph


Posted By: Hogman
Date Posted: Sep/07/2020 at 10:08am
  NICE!!!!!!

     Thumbs Up


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Hogman


Posted By: PHAT69AMX
Date Posted: Sep/08/2020 at 5:16am
And most likely ran that ET using only 1st and 2nd Gear pulling those 2.87 Gears ! Shocked

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Link to a http://www.youtube.com/watch?v=MySiKQsmWxU" rel="nofollow - Short YouTube Burnout Video



Posted By: pipefactory
Date Posted: Sep/08/2020 at 6:05am
Originally posted by PHAT69AMX PHAT69AMX wrote:

And most likely ran that ET using only 1st and 2nd Gear pulling those 2.87 Gears ! Shocked

99.7 in 2nd.  Might have hit 130 if I had another 1/4 mile


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Face distorting torque
10.99@121 mph



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