Dyno numbers for junkyard 360

[Ghinmi]

Ok so I built a junkyard motor so I could take my time building the 401. Never-been-rebuilt 1976 360 that I stabbed a used cam in (.480 lift 224 duration). Swapped the heads for a set with a little clean-up and good springs. RPM intake and holley 750. Just a spare parts engine I threw together in one evening for the price of gaskets. Well it ended up running a lot better than I expected so I threw it on a chassis dyno today.

255.6 hp / 364.1 tq on motor
290.9 hp / 406.4 tq on a 50 shot

Taking into account an estimated 25% drivetrain loss those numbers turn into

340.4 hp / 485.5 tq on motor
387.9 hp / 541.9 tq on a 50 shot

That's almost 1 hp per cube and 5800 RPM out of a motor that could be duplicated with any 360 for around $1000 in a weekend without having to pull the engine. Try that with a 350 chevy.

[Ristow]

not bad.

i have an Offy Equaflow,P.A.W copy of a Performer cam with a 4180 holley on the 360 in my GW while the 391 gets corrected. been in it since last fall.

headers/dual exhaust and a 5600 rpm governor in the transmission.

it revs out good and hard. scoots along surprisingly well.

[AMC-J/20]

Nicely done


Mike

[fulsizjeep]

In my best Darth Vader voice "Impressive"

Originally Posted by AMC-J/20

Nicely done

No 390 comments?

[AMC-J/20]

Well . . .

AMC-390:


490hp@6,000rpm & 492tq@4,500rpm


I may have to rethink those low compression AMC-V8's . . .Nicely done nicely done


Mike

[Ghinmi]

What are the specs on that 390? Pretty sweet numbers! Just curious how my next 401 will compare.

[Greg Taylor]

Pretty cool post! Nice numbers for both engines.

[zachandandy]

Those numbers look nice. Makes me wonder how the 360 was only rated at 129 hp in 77. What ignition system are you running? Stock compession ratio? Makes me want to throw my junk on the dyno.

[AMC-J/20]

Originally Posted by Ghinmi

What are the specs on that 390? Pretty sweet numbers! Just curious how my next 401 will compare.

It's actually not all that altered form the factory specs really . . .

its slightly bored over, and has a slight bit less duration with a little more lift and Eddie performer head's

396Ci, 292*dur .580 lift, Eddie aluminum performer heads, High volume oil pump, Over sized oil pan, and HEI ignition.

The rest is all factory 12.5:1 AMC-390 Cross Ram parts


Mike

[AMC-J/20]

Originally Posted by zachandandy

Those numbers look nice. Makes me wonder how the 360 was only rated at 129 hp in 77. What ignition system are you running? Stock compession ratio? Makes me want to throw my junk on the dyno.

AMC sand bagged a lot of there ratings to stay off the "high Risk" insurance lists

The 68'-69' AMX & Javelin AMC-390 4bbl 10.2:1 was rated for 315 gross horse power Hot rod magazine did a write up on it and found in 100% factory form it actually turned 332 Net horse power after a quick rejet of the carb and recurve of the spark it cranked out 347 N-HP Cost $25-35 Now back that with AMC's optional 3.91 & 4.44 gear's you got a screaming street machine

Mike

[Ghinmi]

Originally Posted by zachandandy

Those numbers look nice. Makes me wonder how the 360 was only rated at 129 hp in 77. What ignition system are you running? Stock compession ratio? Makes me want to throw my junk on the dyno.

Ignition is a gutted HEI dizzy with a MSD 6al-2 and remote blaster 2 coil. Forgot to add that it's got shorty headers too. Stock compression, bottom end never been apart. Stock heads are good, just choked off by the stock intake, manifolds and cam. Fix them and you can pump more air = more power.

Originally Posted by AMC-J/20

It's actually not all that altered form the factory specs really . . .

its slightly bored over, and has a slight bit less duration with a little more lift and Eddie performer head's

396Ci, 292*dur .580 lift, Eddie aluminum performer heads, High volume oil pump, Over sized oil pan, and HEI ignition.

The rest is all factory 12.5:1 AMC-390 Cross Ram parts


Mike

Cool build! I'm doing a 10.5:1 iron head engine with a similar cam and a torker intake. It may see some time on the engine dyno so it'll be interesting to see how they compare.

[shackwrrr]

My stocker with a 4 barrel made 175 hp and 285 tq on a chassis dyno. That was in the dead of winter with 0% humidity. I later installed a melling cam and it made the exact numbers but at 100 percent humidity and it was about 90 degrees outside. I havent been back since.

[AMC-J/20]

AMC-V8's


Mike