401 for drag racing

[barneybrendan]

finaly managed to get a 401 here in the uk.just came in from usa.im after as much detailed info as possible on building this engine.i want to be aiming for around 750-800hp in a 2000lb car,which will be street legal.
amc engine people over here are non excistant.so if anybody has a run down on how to get this sort of power out of the 401 i would be most gratefull

[jeepsr4ever]

To achieve this kind of power you will need major head work. Flow should be around 310-320 @ .700lift on the intake and near 235-240 @ 700 on the exhaust. The crank shaft should be offset cut and ground to accept 2.00" chevy journal. Read this about stroking your motor

http://i2.photobucket.com/albums/y29/bulltear/pssible401sto.jpg
Available as a .dxf as well

4.128 stroke Acura/Mitsubishi bearing 1.771 id

0@450CI
.010@452CI
.020@454CI
.030@456CI
.040@458CI
.050@461CI
.060@463CI
.085 (Big block chevy bore) @468CI
____________________________________________

4.010 stroke Honda bearing 1.889 id

0@437CI
.010@439CI
.020@441CI
.030@443CI
.040@445CI
.050@447CI
.060@450CI
.085 (Big block chevy bore) @455CI

_____________________________________________

3.899 stroke Chevy bearing 2.000 id

0@425CI
.010@427CI
.020@429CI
.030@431CI
.040@433CI
.050@435CI
.060@437CI
.085 (Big block chevy bore) @442CI


These are based off the std 401 bore of 4.165 and using a 401 crank that started at a good cleanup @.030 (after offset grinding) at the top of the journal. This is just a nice reference for those who are thinking of different combos.


Acura/Mitsu journal (4.128 stroke)
6" rod 1.144 compression height piston
6.125" roc 1.019 compression height piston

Honda journal (4.010 stroke)
6" rod 1.203 compression height piston
6.125" rod 1.078 compression height piston

Chevy journal (3.899 stroke)
6" rod 1.2585 compression height piston
6.125" rod 1.1335 compression height piston

Based on a 9.208 deck height (stock 70 and up without any machining done to the deck!)

58cc heads (compressed head gasket = 10cc) = 68cc - 10cc vlave relief

58cc compression ratios

Acura/Mitsubishi (4.128 stroke 30cc dish and 45cc dish)


30cc vs. 45cc dish
0@11.47-9.949
.010@11.5-9.989
.020@11.56-10.02
.030@11.61-10.06
.040@11.68-10.12
.050@11.73-10.16
.060@11.77-10.2
.085 (Big block chevy bore 2.25) 11.89-10.30

Honda (4.010 stroke 30cc dish and 45cc dish)

30cc vs 45cc
0@11.17-9.69
.010@11.21-9.73
.020@11.26-9.77
.030@11.31-9.81
.040@11.38-9.869
.050@11.42-9.909
.060@11.47-9.949
.085 (Big block chevy bore 4.25)@11.59-10.04

Chevy (3.899 stroke 30cc dish and 45 cc dish)

30cc vs. 45cc
0@10.89-9.452
.010@10.93-9.491
.020@10.98-9.531
.030@11.03-9.571
.040@11.07-9.611
.050@11.12-9.65
.060@11.17-9.69
.085 (Big block chevy bore 4.25)@11.28-9.79


Lets say we are looking at a piston for a Blower/NOS application we would want at least a .300 top ring land. We could be looking at a distance of .900" from the bottom of the oil control ring and with a .927" chevy pin and a compression heights of

Acura/Mitsu journal (4.128 stroke)
6" rod 1.144 compression height piston
6.125" roc 1.019 compression height piston

Honda journal (4.010 stroke)
6" rod 1.203 compression height piston
6.125" rod 1.078 compression height piston

Chevy journal (3.899 stroke)
6" rod 1.2585 compression height piston
6.125" rod 1.1335 compression height piston


We are looking at a possible total from top of piston to top of wrist pin to be

.927/2 = .4635 + .9 = 1.3635 (For the lowest possible compression height without having the lower oil control ring touching the top of the wrist pin bore using 5/64 rings .300 top ring land)

Now we know that 1/16 rings are a better choice and are stock on chevy motors and when you use a .927 pin you are in fact using a stock size chevy pin so lets use their better ring choice and recalculate the optimal height.

.927/2 = .4635 + (.9 "at 5/64 ring" - {.0781(5/64) -.0625(1/16) = .0156 * 2 = .0312} = .8688 ) = 1.3323 (For the lowest possible compression height without having the lower oil control ring touching the top of the wrist pin bore using 1/16 rings .300 top ring land)



Acura/Mitsubishi 1.144 compression height 6" rod the oil control ring groove enters the wrist pin bore by .1883

Honda 1.203 compression height 6" rod the oil control ring groove enters the wrist pin bore by .1293

Chevy 1.2585 compression height 6" rod the oil control ring groove enters the wrist pin bore by .0738

Now I do know Chevy LS1 (NOS/Blower application), Chevy small block (NOS/Blower application), BBC (nitrous domes), Ford Boss 302, and Ford big block 385 all use oil control grooves entering the wrist pin bore so I dont see an issue there.

So custom rods and custom pistons will be required as well as possibly a 4 bolt main setup or a stud girdle. For that kind of horsepower you will need a dual 4bbl high rise intake and a couple of 750 dominators. Your asking for a motor that will spin 75-8500rpm for that kind of hp at least. That makes for poor street manners. Fastrouge here on the baord has alot of great info on racing fuel injection and may be a good resource.

[jeepsr4ever]

Your camshaft should have about 290-300 degrees of duration with at least a lift of .700. This means you will need some serious valve springs, keepers and a roller cam setup. It can be done it just gets expensive.

[barneybrendan]

i know its going to be expensive,but i dont know of anybody in the uk using an amc engine to that potential or evan using 1 at all .i had my 360 for years and loved it.street manners wont be an issue as its only to drive to local meets about 25 miles away.
im not realy an engine person in respect of what to do .im 1 of those that if someone said put that in there i can do it no problem thats why i asked for the detailed run down .my thing is more building the car.

[82Waggy]

Check out Indy's 500ci 850HP bracket master AMC engine.

http://www.indyheads.com/id3.html

[jeepsr4ever]

Check out Indy's 500ci 850HP bracket master AMC engine.

http://www.indyheads.com/id3.html

If you dont mind spending 20K..I know it can be done cheaper :wink:

[barneybrendan]

maybe later on .want to use the original engine realy.plus havnt realy red of anyone using it to see what its realy like .

[82Waggy]

I was not suggesting that you purchase an Indy engine, but offering it up as an example of a build making the kind of power you were looking for.

IMO it is going to take alot of expensive prep work and aftermarket parts to get that kind of power out of stock core components - if you want it to stay together very long.

Cheaper than $20k? I've got nearly half that in my relatively mild 401 build with warmed over stock heads and blueprinted stock core components and it is nowhere near the level it would need to be for 800hp. Take a look at Blown7's build or Ken-P's Challenge motor - and they don't make 800hp.

I think you would be looking at Indy heads, aftermarket nitrided stroker crank, Corillo or equivelent rods, custom pistons, splayed 4bolt mains, line hone, good bore sleeves, fix block core shift, and on and on. That is about $8k+ in just parts not including all the stock stuff and custom machine work.

BTW: Are you planning to use any power adders like nitrous or forced induction?

[jeepsr4ever]

Yes easy to put 10K into this motor :shock:

[barneybrendan]

wasnt planning on any power aders but if needs be then i dont mind.reference 8-10k is that in your money or mine

[82Waggy]

wasnt planning on any power aders but if needs be then i dont mind.reference 8-10k is that in your money or mine

Yours I hope! - USD.

That estimate is just for the parts I mentioned. I think you will easily spend 20k having someone build this for you.

[radamx]

bored .085 to 4.250.
crank offset ground to large journal 2.100 chevy rod and 3.825 stroke.
Indy 401-1 heads and intake.
702,722 lift 274,280 duration at .050.sollid roller.
6 inch chevy rod ,custom JE pistons 13.2 ot 1.

this engine was built to run on nitrous so it is not maxed out on the motor.It could make more if it was built to run without the nitrous.

motor pull
741.6 HP at 7500 rpm
572 ft torque at 5800 rpm

1st stage nitrous 200 hp
942.9 hp at 6800 rpm
851.0 ft torque 5700 rpm

2nd stage nitrous another 200 hp total of 400 hp.
1162 hp at 7300 rpm
1000.8 ft torque at 5800

there is a lots of ways to do this it is not that hard to get the results you are looking for .I would suggest looking at heads before doing anything else. for that power level.you will need either the Indy heads,Hermin lewis or Brewer heads. just depends how crazy you want to get.

[82Waggy]

Hey rad, did you bore stock cylinders to 4.25?

[Blown7]

I know now I would not build a stock cast iron block to over 600 HP at 6000 RPM ever again.
I did have good luck, (and hope to for the long term future) but when you look at the aftermarket part prices that you will have to spend to use the OEM block and still have a 30 yr old piece of Iron holding it all together I would at least spend the 4 thousand US dollars and start with a Indy block and crank to get that high horsepower and reliablity.
If you are looking to get in RADAMX's league of over 1000 HP I'd hate to see your crankshaft break and send it all down the tube.( I understand he does have a aftermarket crankshaft.
I myself have over 30K US dollars in my engine but 18K of that is poweradders and electronic engine management.

Jeff

[barneybrendan]

ok lets say keep the motor to the 700hp region with nos would that be an easier solution or cause even more of a headache.car not planned to be completed until easter 2009 so build can be steady anyway.

[milnersXcoupe]

What Transmission / Rear Combo do you have in mind to hook to an AMC 401 to take 800 HP - if you don't mind my asking ?

I suggest you read everything on this site - then:

Build your 401 for 550HP > have Crane Cams cut you a Hydraulic Roller Camshaft > use Forged Pistons > extra head bolt > '0' ring heads /cyl. > have 'Bulltear' mod you an Edlebrock intake for Fuel Injectors > use a belt Driven Supercharger - not 6-71 - style > or use Turbo Charger[s].
:t:

For a 25 mile drive - you won't know the difference between 600 or 700 HP as you won't be able to pull a 'Quid' off the dash when @ WOT in second gear - with simply 500HP - in a 2000 lb. car ...... heLO?

Building for 500-550 , your engine will last and your investment can be driven anywhere simply by rolling off the Boost.

If you want more - buy the INDY AMC engine and Turbo Charge that to 1200 HP - by adding more Boost & Fuel.

Were'nt 'MERLIN' Aero Fighter Engines 1200 HP ?
:razz:

[82Waggy]

Here's a build article for a 390 making about 540hp. Should give you some ideas.

http://www.hotrod.com/techarticles/engine/113_0403_amc_390_engine_build/index.html

[barneybrendan]

ok just been on a fiew sites using the estimated 1/4 mile times .so 2000lb car with 550hp roughly in the low 9s obviously depending on gearing .so maybe thinking of more hp is overkill for the time.
looking back through old posts this sort of hp seems a more realistic capability.the idea of turbos was my first thought when i had the 360 motor but was advised then to get a 401.
ref box 727 axle ford 9"

[milnersXcoupe]

Everything I've read - been 'advised' - is that the 360 cast crankshaft is fine with 500HP. - but stop there.

Weak point has been the cast connecting rods and the lack of swaps as the big end is wider - .

Mad Dog Racing now sells SCAT AMC 360 Forged 'H' Beam or 'I' Beam conncting rods.

A 360 Cast Crank weighs as much as 15 lbs. less than a 390 / 401 - I've heard, as no one here has weighed them side by side or is talkin' ....

A 360 block I have heard is some 40 lbs. lighter than a 401 - I have heard - as no one here has weighed them side by side or is talkin'....

I was all set to install a 'needs alot of work' stock 401 crankshaft in my 1978 360 - but have decided to save the weight and the money - and spend that on a Turbo or Two.

I've a 2004 Lexus A761E 6spd automatic 'warmed' by IPT :

http://www.ipttrans.com/

trans is good for 450HP - and on the Street - I won't know the difference of '50HP' after surviving 450HP with 6 speeds and a lo rear........

For what you've explained - go with Stock Heads freshen'd after a call CRANE Cams in Florida for a 'Custom' Turbo grind Hydraulic Roller Cam Kit / extra head bolts / O-ring heads to block / ARP everything / OIL MODIFICATIONS ala 'Bulltear' / take a look at EDELBROCK's mpfi for AMC as you can swap out easily available parts to fit your build and pick up two nicely sized Turbos.

Run to the Beach using very little Boost on 8 to 1 Forged - then spin the Boost up to punish the local Bizzarrini 5300 GT Strada -



"A Perfect World" =D>

[radamx]

I know now I would not build a stock cast iron block to over 600 HP at 6000 RPM ever again.
I did have good luck, (and hope to for the long term future) but when you look at the aftermarket part prices that you will have to spend to use the OEM block and still have a 30 yr old piece of Iron holding it all together I would at least spend the 4 thousand US dollars and start with a Indy block and crank to get that high horsepower and reliablity.
If you are looking to get in RADAMX's league of over 1000 HP I'd hate to see your crankshaft break and send it all down the tube.( I understand he does have a aftermarket crankshaft.
I myself have over 30K US dollars in my engine but 18K of that is poweradders and electronic engine management.

Jeff

I agree the Indy block is a good Idea. But the reality for most of us is it is too expensive.
I am saveing for one as we speak.
I am useing a factory block with 3/4 fill of block filler.
I am also useing a factory crank offset ground to a chevy large journal rod.it was cryo treated after grinding.
I hope to build a new engine with the indy block and aftermarket crank in a couple of years .but untill then I have confidence in what I have now .
I think I am pushing the factory crank and block to the limits .So far I have not stepped over the line yet.
the bigest problem I have seen is if you do not have the extra head bolt of some kind .does not have to be big. they tend to leak by the head gasket below the spark plug.
As said above I too have been lucky and hope it stays with me for a long time to come. :razz: :razz: :razz:

[barneybrendan]

anybody got any pics of extra head bolts fitted

[radamx]

anybody got any pics of extra head bolts fitted
These had to be trimmed to clear the spark plug on the 401-1 heads.
I am useing a 5/16 stud from ARP with 12 point nuts counter sunk in the heads.
http://memimage.cardomain.net/member_images/11/web/671000-671999/671473_11_full.jpg

[AMX69PHATTY]

304/360 crank weighed 53 pounds on a bathroom scale.
Dont have a 390 or 401 crank handy.

[barneybrendan]

now thats what im after whats the build cost on your motor radamx

[radamx]

I try not to add up the totals but I think about 15 grand and I pulled a lot of favors.
I have access to a machine shop so labor was not part of the $$$$$.
I do most of my oun work porting ,line hone , balanceing,decking and assembly .
I only paid for crank work and boreing of the block.

[Ghinmi]

304/360 crank weighed 53 pounds on a bathroom scale.
Dont have a 390 or 401 crank handy.

My 401 crank weighs 63 pounds on my bathroom scale.

[1980_Cj7]

That's funny, that's almost the exact amount the stock intake weighs.

[HRST390]

I read alot of assumtions regarding the iron block........You have guys like RADAMX and STICKSHIFTER that are pushing the iron block to the limit(of which they have not found yet) and have had excellent reliability....yet the general opinion I am getting is the Indy block is the way to go....
Personally for me I haven't quit using the stock iron heads, block,or crank....If you want something that looks fast spend your money on all the aftermarket stuff and sell your stock stuff to me...If you want to have a real AMC engine that runs there is not a thing wrong with any of the stock parts prepared correctly.....
401 block 4.195 bore
401 crank 3.8 stroke 2.100 jnl. nitrided
090 iron heads ported
torker intake modified for a dominator carb
hooker headers
720hp @ 7800rpm
jerico 4-speed
3000# Spirit runs 9.60's all day spinning the tires(getting close on rear suspension set-up)
I would tend to listen to people that have real world experience in any situation...not the ones that THINK it should be one way or another....
I have yet to see a 401 block break because the block was at fault...I have yet to see a 401 crank break because the crank was at fault.... :t: :shock:

[HRST390]

I have 10k in my engine carb to pan......it might take a little less or more depending on what you have to start with....

[HRST390]

reliability.......This engine ran all last year...ran the total piss out of it...changed the oil and run the valves is all...over the winter had a few lash caps wearing so I changed them and the oil again.....I will replace the lifters, valve springs and bearings this coming winter 08....
And due to the fact that it is a manual transmission car if there is ever a driveline failure then the engine will come out and replace rod bolts at a minimum or the whole set of rods....this is based on real world experience from people that learned the hard way.....

[barneybrendan]

what cfm dominator are you running and keeping the motor all amc to start with is what im planning on now.the 401 i have is a 1975 .i still have my 72 360 to sell yet (maybe).

[jeepsr4ever]

4.43 bore, 4.2 stroke 14.3-1 compression and cracked the block in the main and threaded holes for the studs. The two outer 4 bolts on the middle three mains survived and I havent pushed a iron block that far since then. I think I found the limit of my abilities with the iron blocks but then again all cores arent made the same. I may try a cry'ed block next time I have money laying around to waste on the biggest and the baddest. If I was flat out drag racing I might be inclined to try a 4.43 bore 3.5" stroke or maybe even a lower stroke number(For high rpm). Setting up for stroke can be tricky and sometimes you will need to press fit a plug into the bore of the rod oiling hole. Have it ground under and weld it up then have it ground down again and then drilled and then nitrided and then cry'oed. Its a extremely time consuming and expensive procedure and thats just on the crankshaft. I love the sport itself but wonder if the effort spent on getting 13-1500 reliable hp is really worth it or possible. I havent built anything over 650hp for about 7 years now.

[tarior]

I have 10k in my engine carb to pan......it might take a little less or more depending on what you have to start with....
Is that a Barry Allen motor?

[HRST390]

Barry Allen engine

8896 Dominator