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401 street strip build

Printed From: TheAMCForum.com
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=95255
Printed Date: Mar/28/2024 at 3:31pm
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Topic: 401 street strip build
Posted By: amx73
Subject: 401 street strip build
Date Posted: Jul/12/2018 at 8:47am
I recently picked up a 71' Javelin that I want to build into a street strip car. I have a standard bore 1973 401 long block. Weisco .030 over, 9.5:1 comp(w.58cc heads) forged pistons, ARP rod bolts. Was going to use the stock heads, Air Gap intake, Holley 750cfm double pumper, Hooker 1 7/8 tube headers.

The cam I have is a hyd flat tappet Lunati that CC used in there 370 build. It was the "small cam",

221/230 @ .050, .484 in/ex lift, 108LSA   Made 437hp@6000, and 470lb/ft torque@3900(but, that motor was 10.5:1 comp)

Transmission is either going to be a TF727(trans go shift kit, and red clutches) with a 10" 3000rpm converter, or a TCI 200r4 with a (2600-2800rpm conveter)  I have the Advanced adapters kit already and have used this trans behind my other 401!

Rear: AMC 20, 4.10 gears, Moser axles, and Eaton LSD

I want the motor to be pump gas and street friendly, and push the car to mid 12's.

What do you guys think about this combo?


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Red means run son, numbers add up to nothin'!



Replies:
Posted By: jpnjim
Date Posted: Jul/12/2018 at 2:53pm
I like it,
might want to tweek the heads a little,
and go with a faster acting cam with a little more lift.

At some point the RPM intake could be your limiting point 

Also those Wiseco pistons are awesome,
but going to .030" the first time through the engine limits you on future rebuilds.

Autotec knows how to make AMC pistons, and will make Standard bore, or whatever you'd need to hopefully save the .030" bore for the next time you rebuild.



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


Posted By: mixed up
Date Posted: Jul/12/2018 at 10:58pm
after building many motors my opinion on cams is go big or go home because I have always put bigger cams after putting the car on the road I run 540 lift 280 duration solid cam on my 290 drive it on the street take it to the strip love the pull it has at top end 0-6500 power curve its fun to drive my opinion the lift it limiting the power. you might see mid 12's on it

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69 amx 290 auto
65 220 290 4spd
80 ford fairmont


Posted By: amx73
Date Posted: Jul/13/2018 at 6:56am
Originally posted by mixed up mixed up wrote:

after building many motors my opinion on cams is go big or go home because I have always put bigger cams after putting the car on the road I run 540 lift 280 duration solid cam on my 290 drive it on the street take it to the strip love the pull it has at top end 0-6500 power curve its fun to drive my opinion the lift it limiting the power. you might see mid 12's on it


I'm not dead set on the cam I have. But, I have it. I thought with the 9.5:1 compression it would limit the amount of lift? I had an issue with a 8.5:1 motor that i used a .540 lift cam and it fell on its face at about 4500rpm. I didn't know it was 8.5:1 because after it was taken apart I realized the engine builder put the wrong pistons in it!!!




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Red means run son, numbers add up to nothin'!


Posted By: amx73
Date Posted: Jul/13/2018 at 7:00am
I have heard that .030 over on a 401 is its limit without over heating issues. The motor in my 73' AMX is bored .020 over, and she runs kinda warm. I will check out Autotec. Even if the pistons are $500-600, it will eliminate some machine shop costs.

Once the motor for my 73' AMX is back together and running, I'm going to drag the other 401 from under the stairs in the barn, and get it apart. To see where its at...

Originally posted by jpnjim jpnjim wrote:

I like it,
might want to tweek the heads a little,
and go with a faster acting cam with a little more lift.

At some point the RPM intake could be your limiting point 

Also those Wiseco pistons are awesome,
but going to .030" the first time through the engine limits you on future rebuilds.

Autotec knows how to make AMC pistons, and will make Standard bore, or whatever you'd need to hopefully save the .030" bore for the next time you rebuild.



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Red means run son, numbers add up to nothin'!


Posted By: Hurst390
Date Posted: Jul/14/2018 at 7:30am
I would run smaller headers on that combo..

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SC/Hurst Rambler

11.62 120

100% Street Legal


Posted By: Greyhounds_AMX
Date Posted: Jul/14/2018 at 1:24pm
I think with that cam you will be right at the edge of what you can run with good pump gas, as the DCR comes out to 7.82, and I've got a conservative limit listed of 7.75 for 93 octane with zero deck. If you can tune the timing right it'll make the most torque that way of course, but I'm sure it'll take some effort. It'd be good to have a distributor or ignition that lets you customize the advance curve easily and beyond what you can do with just springs and weights.

The Car Craft build using that cam was about the same deal, in that they ran just a little beyond what most folks would accept for a DCR limit in that 360, but I expect that all of their dyno testing was done with race fuel so knock wasn't an issue. They'd probably have to back off on the timing curve a little with pump gas.

The cam uses Lunati's UH4 and UH9 lobes, which are their "Baseline Hydraulic" 0.842 lobes that are just a smidgeon faster in the 0.050"-0.200" range than the Crane HMV lobes and intended to be very streetable. They should be nice and quiet and low risk.


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1968 AMX 390 w/T5


Posted By: amx73
Date Posted: Jul/14/2018 at 8:21pm
Checked out the motor. Standard bore, cylinder walls look great, crank is standard and in great shape too! I spoke to Autorec and a set of standard bore forged 10:1 pistons, are $610 plus shipping. I'm going to get the rods rebuilt with ARP bolts.

Heads are 993 castings. I was going to get them rebuilt with some mild porting(gasket matching) and that's it. Air Gap Intake, Holley 4150 750cfm carb, HEI distributor, and hooker 1 7/8 tube headers. TCI 200r4 with 2600-2800 stall, and an AMC 20 with 4.10s and a posi.

Now...I'm not married to the cam I have, and I'm open to suggestions. It's going to be primarily a street motor.
It's going in my other 73' javelin SST, and I'm going to put the 360/727 that's in it in the 71'!


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Red means run son, numbers add up to nothin'!


Posted By: PHAT69AMX
Date Posted: Jul/14/2018 at 10:36pm
Target 1/4 Mile ET in seconds kinda dictates everything...
12.00 sec is tied to 110 mph.  Choose a Target Engine RPM at 110 mph.
110 mph, target engine rpm, and tire size determine Ring & Pinion.
Trans gear ratios, Converter quality, & target engine rpm
determine Shift Points and engine rpm drop gear to gear.
Chose Camshaft for Engine RPM at 110 mph target speed
and Engine rpm drop after each shift...
Max Torque to Max HP, 3 times... this points to what Camshaft...
1-2 shift is usually at a different rpm than the 2-3 shift.
What rpm the motor drops back to after each shift is almost
more important that what rpm the shift is initiated at...

A lot of hot air... but I used it as go-by...
My car shoulda ran 12.00 flat but 12.6x is the best I got...
I was loosing 4.5% to 5.0% somewhere, had the MPH but not the ET.
It was a "cheap" B&M Super HoleShot 3k Stall $400 TF Converter...
It had 5-7% Slip at the top end... probably the culprit...
Needed a "good" 9" maybe 3k Stall ~$1k Coan Converter (less top end slip).
343 block, 304/360 Crank, cast slugs, iron heads, Elgin Cam, Torker, Holley, 3.73




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



Posted By: PROSTOCKTOM
Date Posted: Jul/14/2018 at 11:58pm
Those headers will be to large for that combination and RPM range. It would run better across the entire RPM with stock iron than it will with 1-7/8" headers. Just like over camming you can over header it and your heading there. While I will admit 1-5/8" headers will not look as cool as 1-7/8" your going to be giving away torque and HP. It's all about the combination and with everything else they are way out of place.

Tom


Posted By: amx73
Date Posted: Jul/15/2018 at 9:33am
Sorry, I just re read my post and realized I put 1 7/8 tube. I do have a set of those but, the car this motor is going into currently has 1 5/8 tube Hedmans. And a 2.5" x-pipe dual exhaust.

I've been checking out Comps website and like the specs on the XE262H cam.

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Red means run son, numbers add up to nothin'!


Posted By: mixed up
Date Posted: Jul/15/2018 at 10:06pm
take a look at howards cams they have a nice line of cams for amc

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69 amx 290 auto
65 220 290 4spd
80 ford fairmont


Posted By: amx73
Date Posted: Jul/17/2018 at 5:18am
I spoke to Howard's Cams. Very nice and helpful guy named Eric. I gave him all the specs on my build and this is what he recommended:


.520/.541 lift
235/243 duration @ .050
112LSA

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Red means run son, numbers add up to nothin'!


Posted By: WesternRed
Date Posted: Jul/17/2018 at 5:43am
That sounds better, the XE262H seemed a bit small to me.


Posted By: PHAT69AMX
Date Posted: Jul/17/2018 at 12:40pm
Those specs look a lot like an Elgin E-981-P AMC Camshaft...




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



Posted By: jpnjim
Date Posted: Jul/19/2018 at 3:42pm
Originally posted by amx73 amx73 wrote:

I spoke to Howard's Cams. Very nice and helpful guy named Eric. I gave him all the specs on my build and this is what he recommended:


.520/.541 lift
235/243 duration @ .050
112LSA


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:

http://www.competitionproducts.com/Howards-Cams-Hydraulic-Flat-Tappet-Cam-AMC-V8-290-401-Custom/productinfo/319991/" rel="nofollow - http://www.competitionproducts.com/Howards-Cams-Hydraulic-Flat-Tappet-Cam-AMC-V8-290-401-Custom/productinfo/319991/

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 LOL

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:
https://howardscams.com/rt-4932-downloads.html" rel="nofollow - https://howardscams.com/rt-4932-downloads.html
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.




 


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


Posted By: jpnjim
Date Posted: Jul/19/2018 at 3:55pm
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 LOL
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


Posted By: 6PakBee
Date Posted: Jul/19/2018 at 5:13pm
Originally posted by jpnjim jpnjim wrote:

I just overthink things that I think I understand until they either start to make sense to me or I really screw them up LOL


  Boy, do I identify with that!!think    


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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


Posted By: Red Devil
Date Posted: Jul/19/2018 at 5:19pm
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.


Posted By: PHAT69AMX
Date Posted: Jul/19/2018 at 5:22pm
Agree, I should have used a solid lifter flat tappet cam in my last build...

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



Posted By: amx73
Date Posted: Jul/19/2018 at 7:26pm
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.


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Red means run son, numbers add up to nothin'!


Posted By: mixed up
Date Posted: Jul/19/2018 at 10:43pm
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


Posted By: Juan Montoya
Date 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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