Best way to get 250-300 HP? (AMC 360)

[Mr.Wagoneer]

Depends on whether you want and expect longevity. The real-life cost is more than the initial build-up price. Consider now getting 6-7 mph average forever, and replacing transmissions, transfer case chains, rear-ends, u-joints, and motor mounts you'll keep tearing up...because no way will you reserve all the extra horsepower only for the occasional on-ramp.

Don't get me wrong: For special purposes such as off-road racing or reserved for towing heavy stuff several times a year, that would be wonderful. But I've never seen built-up performance schemes last as long as stock when used primarily for general, frequent road use.

Comes with the territory, But I'm not really concerned with durability, I'm pretty sure a AMC block can handle 300 HP and maintain longevity plus a TF727 can handle that power and torque like it was nothing (because that is nothing to a 727) not to mention my Four wheel drive doesn't work as it is so I'm gonna be ditching it anyways just dead weight now plus stronger motor mounts are easy to fabricate, I'm not thinking about building a 500 Hp monster MAX HP i would go is 360HP cause I think it would be cool to match HP to displacment XD

[Josh D]

It really doesn't take much to get those kind of numbers with a stock compression AMC 360. The heads flow well stock and they come from the factory with large valves. They are very detuned from the factory for mileage and emissions purposes.

Carb, intake, exhaust, cam, and gearing to get what you want. I believe my setup makes those numbers your looking for, and I do own on-ramps! My truck hauls the mail!!

[marshotel]

It really doesn't take much to get those kind of numbers with a stock compression AMC 360. The heads flow well stock and they come from the factory with large valves. They are very detuned from the factory for mileage and emissions purposes.

Carb, intake, exhaust, cam, and gearing to get what you want. I believe my setup makes those numbers your looking for, and I do own on-ramps! My truck hauls the mail!!

Do tell Josh....you know how we love the gory details.... What components are you running? I am interested in the same - increasing torque to own the on-ramps.

[Ghinmi]

I built pretty much exactly what you're talking about. Took a bone stock 360 and added a Comp Cams 270H cam, lifters, and springs. Also put on an Edelbrock air-gap intake, holley carb, and Edelbrock headers. The ignition is upgraded with an MSD box. Aside from that the engine is all original. I put it on a chassis dyno and made 255.6 hp / 364.1 tq to the wheels. Easy as cake.

[marshotel]

I built pretty much exactly what you're talking about. Took a bone stock 360 and added a Comp Cams 270H cam, lifters, and springs. Also put on an Edelbrock air-gap intake, holley carb, and Edelbrock headers. The ignition is upgraded with an MSD box. Aside from that the engine is all original. I put it on a chassis dyno and made 255.6 hp / 364.1 tq to the wheels. Easy as cake.

Which holley? Which edelbrock intake? sorry - not up on the technical lingo - Im a wannabe mechanic that buys parts and has then installed! THat package sounds about right! The only parts on the list that I have installed so far is the edelbrock headers. Thanks

[Josh D]

It's nothing exotic really.

My stepdad is a machinist/engine builder with his own machine shop, so my machine work is free.

It's bored .030 with deck plates. The block was decked a couple thousandths. The line bore checked out so it didn't need line boring. The crank was turned .010/.010, polished, and oil holes chamfered. Stock rods were weight checked, resized, and ARP rod bolts used. Main bolts are stock.
Pistons are cast Keith Black/Silvolite 8.5:1 replacements with Fed Mog molly rings. Bearings are Clevite 77. Head gaskets are Fellpro.
Heads were shaved .005", three angle valve job, hardened exhaust seats, bronze guide liners. A 70* throat cut was done on the exhaust ports to open the throat up a little. I blended the bowls, knocked down the short side radius on the intake and exhaust, and did some general cleanup of the ports. Port shape or volume was not changed. Valves are stock, as are the pushrods and bridged rockers. Valve springs and lifters are Comp Cams. Cam is Comp Cams HE268H. Great bottom end and midrange cam with a slight lope at idle. Timing chain is a Cloyes true double roller. I did the valley line oil mod. The timing cover is a Crown replacement piece and the oil pump gears are Melling.
Intake is Edelbrock Performer with a 1" carb spacer. Carb is a Holley 600 cfm 1850S with a vent crossover tube and spring loaded needle and seats. Distributor is stock Delco with a Pertronix Ignitor to replace the points. An Accel Super Stock coil lights the fire.
Headers are Headman and dump into 2X2.25" pipes into a single Flowmaster with a 3" outlet.

Realistically I would put this motor in the 300-325 hp, 350-375 ft/lb range. It should be a solid, long lasting, non-temperamental motor.

[marshotel]

Ghinmi,
Did you change the gears?

[marshotel]

Thanks Josh! Although you lost me pretty quick there. sounds like my machine shop bill would be significant. Unfortunately for my wallet, I do not have any connections to get this stuff done for less than retail

[Josh D]

Thanks Josh! Although you lost me pretty quick there. sounds like my machine shop bill would be significant. Unfortunately for my wallet, I do not have any connections to get this stuff done for less than retail

Most people wouldn't have some of the machine work done I did for what is basically a warmed over stock rebuild. Example: boring with deck plates cost extra and is to similate the distortion on the block with the heads torqued down. Racers have used this trick for years to free up a little internal friction and it's known to make an engine last longer. Is it really necessary in a low HP build? Not really, but when you can might as well.

As far as the headwork, I feel hardened exhaust seats are necessary, especially with aftermarket cams and stiffer valve springs. AMC V8's are known for burnt exhaust valves. This is usually due to the exhaust seats getting hammered over time and then you lose heat transfer from the valve to head. Stiffer valve springs and fast closing cam profiles will cause the seats to get even more hammered. Worth the investment.

The other head work, i.e. the bowl and port work grinding I did myself. Benifits are in the magnitude of 20-25 hp. Not significant enough to pay for it.

Everything else is just the use of good quaility parts. Stay away from no name things like bearings, gaskets, rings, lifters, etc.

[SnowShoe]

Great question...Excellent answer...

[marshotel]

Most people wouldn't have some of the machine work done I did for what is basically a warmed over stock rebuild. Example: boring with deck plates cost extra and is to similate the distortion on the block with the heads torqued down. Racers have used this trick for years to free up a little internal friction and it's known to make an engine last longer. Is it really necessary in a low HP build? Not really, but when you can might as well.

As far as the headwork, I feel hardened exhaust seats are necessary, especially with aftermarket cams and stiffer valve springs. AMC V8's are known for burnt exhaust valves. This is usually due to the exhaust seats getting hammered over time and then you lose heat transfer from the valve to head. Stiffer valve springs and fast closing cam profiles will cause the seats to get even more hammered. Worth the investment.

The other head work, i.e. the bowl and port work grinding I did myself. Benifits are in the magnitude of 20-25 hp. Not significant enough to pay for it.

Everything else is just the use of good quaility parts. Stay away from no name things like bearings, gaskets, rings, lifters, etc.

Thanks for the tutorial, I appreciate it. My GW is mostly a cruiser. I spend most of my time in it with the family in tow daytripping, camping, cruising the beach. I take it hunting, fishing, light wheelin, pull a trailer for firewood etc. im looking to have a motor that has more punch than stock but not be revved out on the highway at 65. I do love the sound of a well tuned V8 thats for sure. Thats where I'd like to end up - somewhere in there!

[Ghinmi]

Which holley? Which edelbrock intake? sorry - not up on the technical lingo - Im a wannabe mechanic that buys parts and has then installed! THat package sounds about right! The only parts on the list that I have installed so far is the edelbrock headers. Thanks

The intake is a Performer RPM air-gap. The carb is a 750HP double pumper and completely mismatched for this combo. Something around 600 cfm with vacuum secondaries would be best. The 750 was all I had handy and it works OK but not great. Yes, I did change gears to 4.10s.

[marshotel]

The intake is a Performer RPM air-gap. The carb is a 750HP double pumper and completely mismatched for this combo. Something around 600 cfm with vacuum secondaries would be best. The 750 was all I had handy and it works OK but not great. Yes, I did change gears to 4.10s.

What are stock gears for an 87 Grand Wagonner with the 5.9? 3:73? I like the cruisability of the present gears but still desire more low end performance.

[smogdredd]

Grunt

Leave the cam alone and raise the compression to 9:1 or 9.5 with aluminum heads, You'll have plenty of grunt and still be able to run premium pump gas. You might be able to pull off 10:1 with aluminum heads but that's pushing it hard for pump premium.

[Josh D]

What are stock gears for an 87 Grand Wagonner with the 5.9? 3:73? I like the cruisability of the present gears but still desire more low end performance.

More like 2.73 or 3.31 if you have the tow package. Are you running stock size tires? Do you have a plan to go bigger?