304 on craigslist

[dalefan88]

i found a AMC 304 on craigslist for $275. it says it has 300hp what do you guys think. i think it would take alot of $$$$$ to get 300hp out of a AMC 304 .

 

[CJ]

Good matched intake, correctly ported and CCed heads, up the compression, larger valves (requires cyl bore notching), correct cam, good headers, more other go fast dodads, MAYBE...

1:1 CID to HP is a tough one to accomplish.

I have spent thousands to get there.

 

[BusaDave9]

Where's the link?
I am curious too. The best that a CJ AMC 304 ever got was AMC 150 horses from the factory. But of course that's factory. AMC 304 Wagoneers and pickups in 1971 got 210 HP. As CJ said mods that can bring the HP to CI of 1 to 1 is possible. During the muscle car era a lot of cars did it from the factory. Nowadays a lot of small engine performance cars do better than that.
I would like to hear what the owner did to get 300 horses out of the AMC 304 . That engine doesn't do good at high RPMs and that is usually where you get the HP.
Check out this link for AMC HP specs: Engine Specs - Jeep Engines

 

[dalefan88]

AMC 304 Engine Strong

sorry it was $250. if i had that much money in it id want more than $250.

 

[CJ]

~~~ That engine doesn't do good at high RPMs and that is usually where you get the HP. ~~~

Yep - all AMC 304 components are cast - weak. I did shot peen my rods to 12N (alman strip standard setting). Tufftriding the crank is really necessary, as well as cross drilling and a crank scraper or you will never get the RPMs you need to achieve those HP levels. You also need some pretty complicated oil gallery modifications. Expect to spend big bucks for 300 hp out of a AMC 304 .

When I dragged, my little AMC 304 reved to 7+,

 

[CJ]

AMC 304 Engine Strong

sorry it was $250. if i had that much money in it id want more than $250.

Looks like a stock AMC 304 - I'd still pay 250 if I could see it run.

 

[dalefan88]

Where's the link?
I am curious too. The best that a CJ AMC 304 ever got was AMC 150 horses from the factory. But of course that's factory. AMC 304 Wagoneers and pickups in 1971 got 210 HP. As CJ said mods that can bring the HP to CI of 1 to 1 is possible. During the muscle car era a lot of cars did it from the factory. Nowadays a lot of small engine performance cars do better than that.
I would like to hear what the owner did to get 300 horses out of the AMC 304 . That engine doesn't do good at high RPMs and that is usually where you get the HP.
Check out this link for AMC HP specs: Engine Specs - Jeep Engines

i know what you mean about more power out of smaller engines. my 03 honda accord with a 2.4l 4 cylinder has 161 horsepower. thats like 50 more than my inline six jeep with probally alittle less torque.

 

[ken98k]

i know what you mean about more power out of smaller engines. my 03 honda accord with a 2.4l 4 cylinder has 161 horsepower. thats like 50 more than my inline six jeep with probally alittle less torque.

Chevy has v-6s putting out over 300hp.

 

[BajaEdition]

HP is a very deceptive number
Chrysler can get way over 200 out of a 4 popper
but at what expense

Low end torque

most high hp to cid ratios are done by getting the HP way up in the rpm range, and stressing that range up in numbers we would not try to acheive 40 years ago.
Look at a modern (no not a neanderthal Harley) motorcycle engine of 1200 ccs pushing 180 hp, that is what 73 cid with 2.47 HP per CI. Now take that same engine and put it in a jeep and see how far down a trail you get.

We as Jeepers want low end torque, and that does not translate into high HP engines per sey, What it does mean is larger jugs per CI and that is why some of the best of our engines have not been v 8s but 6s and 4s.
those same engines that guys hate on the road they swear by in the dirt.
Look at Jeeps AMC 258 i6 / 4.2l and 4.0 engines, neither of them are known for being able to scratch a set of tires in third gear but how man guys run them here on this board and would rather fight than switch.
Not to mention the 134 in both flat and f head configs, 80 hp new when tested at the factory dyno, and that was the final version, but legendary engines still being run today in very large numbers.

 

[CJ]

Chevy has v-6s putting out over 300hp.

Modern electronics, modern technology...

Try getting 1:1 with 70's or even 80's engineering - very difficult.

 

[dalefan88]

i know i want to trade in my accord for a acura tl. thing get high 20s mpg and has almost 300 hp. but you guys are right about jeep engines. i love my inline six. people tell me to drop a v8 in it all the time. for what i do with my jeep the inline is just fine.

 

[Old Dog]

Modern electronics, modern technology...

Try getting 1:1 with 70's or even 80's engineering - very difficult.

You got that right, takes a lot of money and machine work.
And as Baja noted as horsepower goes up it's in the higher rpm range and at the expence of torque.
But you can make a v8 a torque monster if you buld it right.

 

[dalefan88]

You got that right, takes a lot of money and machine work.
And as Baja noted as horsepower goes up it's in the higher rpm range and at the expence of torque.
But you can make a v8 a torque monster if you buld it right.

yep its called a stroker lol. i have a couple of buddies with 383 strokers in their chevys and one with a 347 stroker in a mustang and all 3 have tons of torque. all 3 can melt the tires at will.

 

[CJ]

350 / 383 / 400 Strokers are easy with SBC, AMC's - not so much. There are so many interchangeable GM parts.

You can destroke an AMC but it takes bucu bucks! Trust me - I know...

 

[BusaDave9]

Here are some specs. All of these numbers (except the dragster) are non-modified from the factory specs.
.
1975 Jeep CJ5 AMC 150 HP with AMC 304 CI Engine = 0.49 HP per Cubic Inch
1969 Camaro 425HP with 427 CI Engine = 0.99 HP per Cubic Inch
New Ford Mustang 194 HP with AMC 232 i6 CI engine = 0.83 HP per Cubic Inch
Porsche Boxter 295 HP with 207 CI engine = 1.4 HP per Cubic Inch
My Hayabusa 145 HP from a 79 CI engine = 1.83 HP per Cubic Inch
Top Fuel Dragster 8000 HP from a 500 CI engine = 16 HP per Cubic Inch
.
Then comes the topic of horsepower to weight ratio.

 

[BajaEdition]

Busa, nice figures, let me point out something though
that 69 camaro, with the high hp figures
It has a special casting number on the block. You are not going to take any 69 block and get those kind of figures out of it.
1 to one was extremely difficult to get in that day and that was a special engine.

 

[BusaDave9]

Busa, nice figures, let me point out something though
that 69 camaro, with the high hp figures
It has a special casting number on the block. You are not going to take any 69 block and get those kind of figures out of it.
1 to one was extremely difficult to get in that day and that was a special engine.

if you went with the 302 engine in that '69 Camaro you would get 290 HP
A '61 Chrysler 300 got 385 HP from a 413
1970 Dodge Coronet with a 440 got 390 HP
1970 Dodge Coronet with a 383 got 335 HP
1969 Dodge Charger with a 426 got 425 HP
1967 Ford Fairlane 500XL with a 427 got 415 HP
1969 Mustang Boss with a 302 got 290 HP
1969 Mercury Cougar with a 390 got 320 HP
A have a book of collectible cars and there are a lot of muscle cars that made up to 1 to 1 right from the factory. Google verifies these numbers.

 

[BajaEdition]

Busa, what I was pointing out is that those high HP motors do not even share the same blocks with engines that are a lot lower in HP
example, you get a early body without a motor and run the numbers looking to see what exactly you have. Comes up it was a 69 zl 1 with a 427
that was an aluminum block engine with 450 hp that only 69 were built to homologate the car for Transmission am racing.
so now, go find a block for that. or heads or even valves. not stock items at all.
more typical for the day was a 327 rated at 210 HP

Lots of special engines in the day, HP was king, but the majority of all the Camaros, Mustangs, darts etc came with inline 6s. Base modles out sell upgrades even today.

 

[BusaDave9]

These are not special high performance engines. They are production cars the dealers had on the showroom floor. Everyone expected high horsepower. Look over my list. The '61 Chrysler 300 isn't even a performance car. It's a family car. Chrysler (unlike other car makers) usually only offered one engine for each model. So if you wanted a '61 Chrysler 300 you better be able to deal with 385 horsepower because there was no other options. Check out this link:
Chrysler cars, 1924-1966
Start looking at 1960. There is a 375 HP station wagon. No other engine options.
In 1962 you get 405 HP out of a 413 CI engine.
The book I have been referencing has production numbers by year but not engine. So maybe a lot of the Darts and Mustangs did come with a six cylinder.
My point is that during the '60s and very early '70s it was easy to get an car with almost 1 to 1 ratio of horsepower to cubic inches. And yes, there are also low HP options too.

 

[CJ]

We have got WAY OFF tangent of this thread -

On topic or closed...