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Max HP for an amc 360

20K views 15 replies 9 participants last post by  **DONOTDELETE** 
#1 ·
What is the MOST horsepower that AMC put out with a 360 in any automobile? EVER? I need facts, have a friend that swears his 360 out of a (rambler?) has 425hp. Does anybody have anything to shut him up with?
 
#3 ·
Your friend is delusional. It might be best not to argue with him - just smile and say "Oh, really? I had no idea they were so potent!" He doesn't own any firearms, does he?

Unfortunately, you're in a position of 'disproving a negative' here. He can claim that it's a super secret development engine, done for the Trans Am series - Team Highball and all that.

If you really want to shut him up, and he doesn't own firearms, take the car to a shop with a chassis dyno, and see what numbers it makes.
 
#4 ·
The most I know of for a 360 is 245HP and 365lbs/ft torque. There were undoubtedly more powerful engines in the AMXs, Javelins, and maybe Matador police cars. But as I remember, the high HP engines were 390s and 401s.

360s were good torque motors, but were limited in power by some pretty weak heads. My guess would be that your friend's motor is race built, to put out that kind of power

There's alot of AMC info on the net; probably some definitive engine specs.
 
#5 ·
Unless your friend has had alot of work done it is unlikely his 360 makes that kind of power, possible yes, but not likely. There`s a saying," The dyno don`t lie". Refering to 360 AMC heads as "Weak" though, Is completely inaccurate. All 360 AMC heads from the factory were equiped with 2.025 intake/1.680 exauhst valves, And due to the dogleg port design, flowed better than most small block head designs. Some very credible numbers can be put up by AMC heads, Almost 300 cfm per cyl., From a port and polish job. Don`t let anyone sell you short on AMC motors, They`re beter than most people want to admit.
 
#7 ·
Aren't the numbers for the AMC engine before 1971 rated "gross" rather than "net", making them appear more powerful than they really are?


I just find it hard to believe that in 71, an AMC 360 made 285HP in 71, but in 74 makes only 195HP.
Parasitic power loss shouldn't amount to a 90HP loss.
<shrug>
Just something that confuses me...


Anyway, as was suggested already - take him to a chassis dyno and let him run a few times and then average the numbers out. That'll shut him up.
There's only one public chassis dyno in Albuquerque, and they charge $50 for 3 runs or you can rent the dyno for an hour for like $80.
Of course, pricing in your area may vary.
 
G
#8 ·
The 1970 4 bbl. 360 was rated at 290HP@4800rpm, 385ft. lbs. of torque @3200rpm. This was a 10.25-1 compression engine, while the 2bbl. was 9.0-1. 425hp from a 360 isn't unheard of, but it won't have to many "stock" parts. Mildly modified dogleg heads will easily support 400hp.
 
#9 ·
Yes, the numbers for `71 and prior are gross, And `72 up are net. The reason for the HP difference between those years are due to combustion chamber volume and differences in piston profile. The early AMC heads had a 51cc chamber volume as opposed to 58cc for the later style.
 
G
#10 ·
Don't forget about stricter emissions too, that killed a lot of power out of the AMC motors. The 304 head comment is totally true, they suck! I wonder how a 304 with 360 heads would perform? I bet it's just a smaller version of a 360 with 401 heads
It takes a lot of work to turn a 360 into a HP monster, especially with the oiling system, these motors weren't designed good from stock to turn high revs.
 
G
#11 ·
360 heads will bolt on a 304 block, but the tops of the cylinders need to be notched for intake valve(2.02 for the 360, to the 1.787 for the 304) clearance, & even then, the small bore of the 304 can't take advantage of the larger valves. I've seen 304 heads on 360's, & it makes for great torque for about 50 feet, but then they're all done. They do respond pretty well to larger 1.94/1.50 Chevy valves & mild porting for a "hot" 304. The 304 gets cast aside, but they are actually good little engines. True, the AMC dosen't have the best oiling system for high rpm's, but they don't really NEED to be wound tight to make power, even in a drag race situation.
 
#12 ·
Although 425 seems a little high I believe that you can get a 360 up to 300 ish. I was thinking my engine gets around 240hp but I could be wrong. It is an 82, has edelbrock performer intake, Tbi, headers and low miles. The reason don't like the hp ratings is because 90% of them are done at different rpms so it is hard to compare different engines.
 
#14 ·
Thanks for the response. It`s just that the boys at the body shop are getting tired of hearing the owner say it, ALL the time. One of them asked me to get some facts. I will give this print out to him. P.S . I drove the jeep ysterday to try out his reverse shackle. I would rate the motor at about 190 tops
I hope the 350 I am building will have a little more low end than his 360.
 
G
#16 ·
Jeeplvr, the main thing is checking clearances in the oil pump to make sure they're in spec. For high rpm use, a popular mod is a line inside the lifter vallev from the front of the block to the intersecting galley's over the #4 main feed. I have to disagree with the failure of distributor gears being due to lack of oil. These gears are pressure fed oil & I know of more than a few engines that have munched these gears even with the external feedline. The wearing of the gears is most commonly from cam walk or mis-matched gears. Although I have run gears from 2 different engine without failure, it is very common for gears that haven't been run togther from new to fail. I haven't seen the other links mentioned, so you may see some duplicate info. there are other oiling system mods for race use, but for lower rpm deals, checking specs & clearances are a good way to insure long engine life. You're right about the power....I built a stock(except for an RV grind cam)360 for a friend who put it in an '80 CJ-5. Yikes !! That thing was a blast to drive !!! It caught many a "race" car off guard in stoplight duals, & also made for some adventure's off-road !! lol Hope this helps...
 
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