400hp out of a 360 AMC (discussion)

[jeepsr4ever]

This is taken from my posts on another board and may help some builders here, let me know if I left anything out.


recipe for a 400hp 360

p.s. easy to do

360 bored over at least .030 (.060 if you dont mind block filler)
ported heads mostly behind the valves and enlarge teh ports to the intake and exhaust.
headers .....stock manifolds do not flow as well (some older AMC cars guys will argue this with the free flow manifolds.but its bs)
Valve train you will need springs in the 110-140 area for this buildup
Roller rockers (chevy rockers work {1.6 ratio} or harladn sharps although when your over 6500rpms the poly locks break) you will need guideplates for your pushrods and dont run guideplates without moly pushrods
Solid lifters (forget hydraulic they are a huge waste of power and energy) or Roller lifter (roller lifters are the top dog for building power but depending on the company you buy from you may need to have the lifter bores bored and sleeved)
Take your cam bearings and drill a .201 hole in them and use that hole for your oiling (every bearing but the front cam bearing {it feeds the dizzy gear})
drill out your mains to .339 {letter R or a 11/32 drill} make sure to drill out your bearings as well, we always do the last 4 bearings.
Cross drill that crank (400hp is alot on a butter crank like the 360 crank any more and you can cause over stress of the crank and major thrust bearing wear that can attribute to piston pin landing damage and un constant knock which also break rods and makes engine builders unhappy cause you just punched a hole in that block)
Camshaft..this is one of the most important things you will do. You must use a quality cam with a solid or roller rocker lifter. Comp cams 280 or 290 are great for this
Oil pump...do not build around a used oil pump, they are cheap enough today to replace when building an engine. Bulltear sells em cheap and so does performanceamstyle.com and a ton of others.
oil filter adaptor do not use a old adaptor without either plugging it (where the oil filter bypas is or replacing it with a new upgraded one with that area cast in (chrysler found out in the late 80's that this was a bad idea and suddenly the engines were lasting longer.
Deck height what is ideal is a zero deck height and a minimum of .042-.044 quench for rod stetch and crank twist between top of piston and head. We make copper head gasets in a .030 (this will not work with a zero deck height...you may need to run fel pro at .046 or ROL gaskets if you deck your block)
Intake...400hp is a fair amount and you wont get it with a stock 4bbl intake. You want at least a torker if not air gap R4B or a edelbrock MPFI. You can hit that mark pretty well with a cross ram but they require alot of carb and generally hit high hp in the higher rpm 5000-7500, tunnel ram can get you there as well as a blow through turbo or super charger
carb...dotn bother with a edelbrock 600cfm opt for the larger edelbrock or a large DP holley or a demon...predator carbs are great for rock climbing but can be bastard gas hogs as well.
piston compression ratio.....at least 10-1...343 pistons will give you 10.5 to 1 compression this may be too much with the decking for the stock cast rods.
Scat has new forged rods for the 360 coming fast so keep an eye out if you need these at Bulltear.com or fastengineparts.com
you want a good roller timing set and may want to balance the rotating assembly
under drive pulleys help we make those in 10 - 20 and 40 percent aluminum...shameless plug
the really hot spark is required as well as a very high breathing air cleaner...avoid the open top elemnt air cleaners they dont flow better than stock as they will cause air cavitation at the top of the carb. Closed elemnt dual snorkel is always best or a higher air cleaner to get cold air from the outside not warm air from the engine bay.
a dry sump oil pan may be needed if you expect very high rpm's we make a new upgraded sandwich plate that port matches your oil ports for better flow than the Milodon plate of yrs past...check out performanceamstyle.com for info on dry sumps and pans.
a good oil filter doesnt hurt either...avoid fram and instead purchase either Wix and napa gold. these filters are desinged to work with the engine and not a general filters all amterial like you will find in cheaper filters like fram.
when your building above 350 hp you dont want tight as nails crank tolerances you may want to stay around th middle of the tolerance for a strong hi hp motor


We also suggest for long term oiling modifications to your oil pump like this one, we explain the tech so you can hae this done yourself or we sell them done complete


Here is member brad arthur's nickle coated timing cover after eating 3 sets of gears. We found the height of the distributor gear to be wrong (not a cover defect) Normally one sets of roached gears will eat the oil pump up to the point of very low efficiency. The nickel not only protected the pump but the pump is still in spec after the nickel was chewed away and that is only a small amount but their is still sufficient nickel left over to give the pump many times longer service life than pumps without the nickel coating. Here is the proof

http://jeepsr4ever.imgbay.com/timing%20cover.JPG


and here we see the oil filter adaptor with cosmetic scratching and a very small amount of nickle worn out, the nickel is just worn on the surface of the stock grooves and will still protect the pump for may many years.


http://jeepsr4ever.imgbay.com/oil%20filter%20adaptor.JPG


here are pics on the sandwich adaptor

1. Port matched for superior oil control and flow
2. hole size opened up for better oiling and less restriction
3. Billet aluminum
4. more material on the tapped holes allows for ZERO restiction caused by over tightening fittings
5. gasket matched
6. available soon with various thickness of gaskets and in different coatings
7. superior oiling angles when compared to all aftermarket pieces


Only avaible at Performanceamstyle.com for 6 months

More Pro part Line up coming soon

http://jeepsr4ever.imgbay.com/Midpl.jpg

and pics of a block that has been bored from the mains...do not bore with cam bearings installed!!!!

http://mpcrescenzo.imgbay.com/DISPOSE%20001.jpg




With the help of Frank in norways website

Lets stay on track and do a little learning between wheelers here. I may have gone overbored and that combo I listed may hit the 450-475hp mark...oops. Here is the combo listed from a amc 360 for the dyno below, if the pic doesnt come up please click the link


AMC 360 bored .30 over
Stock crankshaft .10 under
Cast pistons 9:1 comp.
Stock rockers
2.02 int./1.68 ext valves
PAW camshaft 214/224 @050
Chevy chrome-moly push rods
Edelbrock Performer Manifold
Holley 600 carb.
K&N 14x5" Air Filter
Jacobs Ultra-Team ignition
BlackJack headers
Custom 2 1/2" dual exhaust


http://www.fullsizejeep.com/1024/pics/drivetrain/dyno3.jpg
http://www.fullsizejeep.com/1024/pics/drivetrain/dyno3.jpg



Well, I have not had the chance to do an actual dyno test. I did however do several computer simulated test that showed me a peak Hp of 364 at 5500rpm and a peak torque of 400 at 4000 rpm. The torque was 361 at 2000rpm. This is the bare engine so I suspect different numbers at the wheels :-)) I also simulated a run down the 1/4 and ended at 13.91/102.3mph with my 35" mudders. I suppose the day I'll try the Wagoneer on the strip will never come, but it's nice to know :-))



And the original 360 and the rebuilt one on the dyno
http://www.fullsizejeep.com/1024/pics/drivetrain/dycompare.jpg

http://www.fullsizejeep.com/1024/pics/drivetrain/dycompare.jpg

[Woody Long]

Would these work for this application?


"Roller Rockers for a chevy small block. 1.5 Rocker Ratio. Roller Tip and Rocker. Will Fit : Chevrolet V-8 55-87, 262 thru 400"

[ol' school power]

Why would you want to use a rocker that would reduce the actual valve lift?

[jeepmonster]

This is very similar to how I am building up my 343. Although I am "only" shooting for 360-375 Horespower :? . Here is the combo.

.030 343 pistons
10/10 on the crank cross drilled and polished
blueprinted oil pump assembly
milodon 7 quart oil pan
decked for flatness block
1970 390 doglegs milled just a tad and ports and chambers "cleaned up"
ARP rod, head bolts, and main studs, arp 7/16th rocker studs
Harland sharp 7/16 1.6 roller rockers
Comp Cams titanium retainers and 10 deg super locks
Custom order Crane Hydraulic roller cam 220/222 501/508 112 8)
Rollmaster Torrington bearing double roller timing chain
R4B Intake(BUT with the heat risers blocked) :wink:
Competition Series AFB with modified metering circuits.
1/2" fuel line from tank to pump
Edelbrock Shorty headers or Hooker full lengths (not quite sure how much difference in power there is -one from the other?? But the shorties will put an end to starter removal hassels and scraping on unexpected uneven ground surfaces.
SS/AMX repro carbon fiber hood and large 14"X4" air cleaner tapping the cool air from the scoop.
3.73 rear posi.

68 AMX under 3100Lbs. :mrgreen:

[ol' school power]

I'd be going for more carb than Carter has to offer, but that's just me.

[jeepmonster]

....I was thinking holley as well but it "IS" a 750 AFB. I have already installed high flow needle and seat assemblies and recalibrated the float level. Also did the little known secondary enrichment early feed mod.
On the original combo; stock cam ,hooker headers, and R4B this really woke that carb up. I have the stiffest enrichement springs on the primary side with the original 750 calibration rods and primary jets. This eliminated the minor flat spot I had a WOT from rest and low speed rolls and she pulled pretty hard to redline and wanted to keep going-no fall off or flat spots anywhere. Drop it into second and punch it on the highway and it becomes VERY clear why AFB's have been around so long :!: .
Never even had to touch the accelerator pump either. With the new cam, bore and heads, all I'll need to do is fine tune the jet/rod ratio-most likely richen it a bit for the better breathing heads and then maybe might need a pump adjustment with the better cam and increase the jet size on the secondary side, but that should do it. I like the aluminum 2 piece design of the AFB, love holley double pumpers as well, but the AFB flows plenty of air and fuel for this combo and the cost of a holley/demon is way too much to make it an even marginally better choice than the 750 afb foe what I am doing. If I decided to go bigger, an 800 CFM carb is the next step up, and Edelbrock has already taken care of that with the reintroduction of the vaunted 800 CFM dual feed AVS with adjustable air valve.

If I were going with 3.91 or 4.10 gears I'd probably get a 800 CFM double pumper,($$$$)!!! but the 750 AFB can supply plenty of fuel and air for the upcomming combo, works great with the R4B and with the blocked heat to the manifold, the all aluminum carb is going to deliver a nice dense fuel charge. The holleys I used to run were very prone to heat soak, and led to inconsistent performance, I usually had to use a 1" phenolic spacer between it and the manifold , and that did give good results but AFB's "run" much cooler even on a heated intake and spacers are often times just a crutch compensating for mixture distribution problems.

Holleys/Demons are just WAY to expensive, personally I think they have a LOT of nerve to charge so much money for them. They just keep going up and up in price year after year and AFB's have stayed very cost effective. I CAN afford holley and Demon-heck I am spending 500 bucks on a set of hydraulic retro-fit crane roller lifters-so it's not a money thing I'd just rather spend the money on the edelbrock coated shorty headers! :lo1l:

[gremlin boys]

ok i have a 360 that is pushing my gremlin drag car to 11.32 118mph here is my combo360 30 over 9to1 comp mild port and polish heads crane golds 1.6 rockers, airgap intake 750 holley double pumper and believe it or not summits biggest hyd cam cheap headers i even spray this motor with nitrous which puts her in the high tens, no the car isnt stripped at all just missing seats, the tranny is a turbo 400 3500 stall rear is a amc 20 with stockaxels double keyways 3.54 gears, i have been racing and building cars for 25 years i have found that tons of power can be gained with just tuning the complete drive line properly, and it helps one of my best friends has a chassie dyno, the right combo and proper tuning will make well over 400 hp. this is stock rods and crank, i even have a 401 old amc dealership race motor i tried in my gremlin and i didnt believe the guy i bought it from but the power band on that is 4500 and up. i had it on the dyno and at 7400 it was still climbing in the power band, the man told me it shifted at 8800. well my dyno buddy told me to shut it down i asked why well with the 3.54 gears it was pushing 173 mph with a amc 20, this motor allso is a stock crank and rods, Don

[Woody Long]

Why would you want to use a rocker that would reduce the actual valve lift?

I could have got a good deal on a set, I'm not to smart on the whole valve train math and such.

Sorry for the dumb question :smile:

[ol' school power]

One thing with carbs over the last several years is that the numbers ( CFM) do not match between the brands due to the measurement standard used.
So an 850 Demon flows more air than the Holley which generally flows more than the Carter. The old standard was measured at 1.5"/hg. That's a lot of struggle for an engine creating a restriction on top.
For track usage, you don't want more than a .5"/hg reading on top end.
If you're going to play top end horsepower, then don't be bashful with cfm when it comes to AMC motors. The stock 35 year old stock heads on these motors flow more air than many of the factory heads today.
Something else to ponder. Back in 69/70, AMC offered a dealer installed 950 Holley on top of the R4B. That's the reason for the notch between the secondary butterflies ( clearance for the single oval secondary butterfly).

[jeepmonster]

One thing with carbs over the last several years is that the numbers ( CFM) do not match between the brands due to the measurement standard used.
So an 850 Demon flows more air than the Holley which generally flows more than the Carter. The old standard was measured at 1.5"/hg. That's a lot of struggle for an engine creating a restriction on top.
For track usage, you don't want more than a .5"/hg reading on top end.
If you're going to play top end horsepower, then don't be bashful with cfm when it comes to AMC motors. The stock 35 year old stock heads on these motors flow more air than many of the factory heads today.
Something else to ponder. Back in 69/70, AMC offered a dealer installed 950 Holley on top of the R4B. That's the reason for the notch between the secondary butterflies ( clearance for the single oval secondary butterfly).

Good points! I have run a 4150-4779 750 double pumper with very impressive results years back on the old combo and loved it, I also had a 780 vacum secondary holley that I ran out of the box and it ran strong with that carb, didnt loose any bottom end either although I did have to adjust the pump shot on both the 750 and 780 to cover up the "hole" in the transition circuits. Ther is no doubt 343's like BIG carbs so I 'd have to say you'd get no argument from me that AMC's respond to very well to bigger carbs than the equations normally dictate. The 950 3 "barrel" was one bad ass looking carb an I'll bet it had the performance to match. It would be interesting to see how it performed with more modern intake and cam designs. The new Edelbrock (reintroduction) of the AFB AVS was a long time comming an 800 CFM dual feed AFB is nothing to sneeze at. I removed the choke plate from the 750 AFB and didnt notice any ill effects. Since I already have a decent carb and a nice vintage intake, I don't think these parts will be the bottle neck on my combo. I am sure the velocity through an air gap (VS an R4b) is higher however, so a slighlty larger carb with that intake could make for a few more lb ft of torque and horsepower on my new combo-modern induction technology will always have advantages over the vintage parts.

[ol' school power]

My son runs around in the summer with a 79 Spirit, 360, auto, small Summit cam and a torker.
Originally we had a 600 on it, but it always seemed a little flat even with a bunch of jetting and secondary spring changes.
I decided to toss on my old Holley 750 ( annular "list 4011").
Out of the box so to speak, this car picked up 4 tenths in the quarter.
I currently run the 870 Avenger on my 401 and feel like it can still handle a little more. Had I known then what I do now, it would have been a Demon 850 which actually flows more to the middle 900's by the spec Holley uses.

[jeepmonster]

Speaking of CFM, the edelbrock TBI is rated at 1000 CFM!!! Given the precise metering of fuel injectors in the runners, there has got to be tremendous potential over carburators of the same "CFM", especially taking into consideration all around driveability, off idle performance, fuel injections inherent characteristics to compensate for weather changes etc. etc. and the advantages of modern technology become very attractive. :-|

[ol' school power]

I've looked at that too, but idle vacuum requirements changed my plans.

[jeepmonster]

Thats not the same problem that it "used" to be. Modern fuel injection systems are best with wide lobe seperation in the camshaft, so I wouldnt choose a carb over fuel injection based on idle vacuum requirements when it is in FACT the camshaft that is the factor you need to address, instead of running a carb with cams in the 108 - 110 lobe sep and 224-236 deg @.050 a cam with a modern TBI system would work much better with and produce a substantially stronger and wider power band with cams in the 112-116 deg lobe sep "club", mild .050 numbers 210-220 and strong lift numbers .500-520. Much stronger vacuum and earth flattening torque will be the answer. Of course this is all application specific :wink: Just look at the new Vette pumping out 500 horse from a 427 pushrod small block :sa:

[ol' school power]

I'm talking specifically in the engine that i run now. I looked into the Edel system but as a map system, my engine vacuum is too low@ idle.
My cam is a 238 degree, 110 degree separation and just over .500" lift.
Actually a little more since I'm running 1.65 rockers.

[jeepmonster]

I'm talking specifically in the engine that i run now. I looked into the Edel system but as a map system, my engine vacuum is too low@ idle.
My cam is a 238 degree, 110 degree separation and just over .500" lift.
Actually a little more since I'm running 1.65 rockers.

Yeah, that cam wouldnt produce adequate vacuum, if you ever did step up to the edelbrock tbi system a cam swap in the range I specified above would work very well for you and you will see a substantial power gain across the RPM range, nut it WILL be expensive relative to your carb/cam set up now.

[ol' school power]

Looking at it as bang for the buck or horsepower per dollar, I don't see it as a worthwhile investment. For a cruiser where low and mid range is needed, maybe it could do something but time on mine is spent mid to top end ( 3~6K).
Given the same a/f mixture and actual cfm flow ( not advertised), an engine will produce the same power.

[jeepmonster]

Well if this becomes a bang for the buck discusion than Nitrous Oxide is the obvious answer. :wink:

[jeepmonster]

Also might want to look into the comp cams 4X4 cams for AMC/Jeep V8's ! Talk about some nice profiles!! :!:

[ol' school power]

The Extremes are nice. I've had 2 of them custom ground for my 6 bangers.