supercharged 304 build

[brickproof]

ok thanks i found a amc 304 that i liked on this website and they list what they have done to it so this might be a little useful to me http://www.c-dperformance.com/CDP_Engines_Others.html

[tufcj]

I had a 304 built nearly the same (10.5:1 compression, flat tappet cam and torker intake). Ran it in my Jeep when I mud bogged. Spun it to 6500 regularly, lots of guys thought I had a SBC conversion until I raised the hood.

Bob
tufcj

[brickproof]

I had a 304 built nearly the same (10.5:1 compression, flat tappet cam and torker intake). Ran it in my Jeep when I mud bogged. Spun it to 6500 regularly, lots of guys thought I had a SBC conversion until I raised the hood.

Bob
tufcj

any idea the horsepower/torque? could i run that compression on pump gas? how did you get to that compression? sorry about the questions but i have never done anything like this before and only know what iv read online. and i also want the exact same reaction when i raise my hood. that it really the whole reason with building this motor and not a common motor like everyone else.

[tufcj]

Mine was running 350+ HP. I had to run race fuel, it would ping on pump gas, even with the timing backed down (which really hurt HP). To run premium pump gas, you're going to have to keep compression in the 9 to 9.5 range depending on cam specs and dynamic compression ratio. The pistons I ran were forged TRW, I know they aren't made anymore. Google "static and dynamic compression ratios", there are calculators out there. You'll need to know the compression height of the piston you're going to use, the volume of any dish in the piston, as well as the volume of the combustion chamber in the head and cam specs. It all has to work as a team. You see why professional performance engine builders aren't cheap.

I ultimately went to a 360. 1 HP per CU IN is very easy to attain, going past that number is where it starts getting expensive and abusing parts. When I went from bogging to rock crawling, I needed an engine with a much different HP and torque curve. The 304 ended up in a Hornet, my Jeep ended up with a much milder built 360.

Bob
tufcj

[brickproof]

i know making power with the 360 would be loads easier but still want to use the 304. is there a certain route someone can suggest i take in order to reach decent horsepower ratings? i have also heard that forged pistons don't do well in daily drivers...can someone shed some light on that subject as well? i appreciate all the help

[tufcj]

You have to build the engine for the application. There is no "formula", you have to pick parts in a combo that will work together. That's where a professional engine builder will help. A high HP engine will lose some torque, a high torque engine will sacrifice HP. In drag racing, torque makes ET, HP makes MPH.

You need to make any AMC engine breathe. Keep compression around 9-9.5:1, Spend your money on valve/head work. With my 304, 1.94/1.50 valves, a good polish/port, and a cam with about .500 lift really made for a potent combo. Balancing is important for both performance and longevity. Forged pistons work well on the street, but they do require a little more piston/wall clearance, so you may hear some cold "piston slap", and you want to warm up your engine before romping on it. I've been running forged pistons in my AMX 390 for 7+ years with no problems. I built that engine with forged pistons and stainless valves so I could give it a 100 shot of N2O if I wanted to, so far, I haven't seen the need.

Bob
tufcj

[brickproof]

i understand that everything needs to work together and since this is going in my jeep with future plans being maybe 40 inch tires i would sacrifice the horsepower for torque and i will use forged pistons but can the piston slap be prevented? if warming the engine up eliminates it thats fine because i always let my cars warm up plenty and don't ever really plan to romp on it i just want to know the power is there if i ever want to shred some tires or tow something. i plan to keep the jeep on the road 90% of the time. with any luck i will be heading to the machine shop within a week or two *fingers crossed*

[jeepsr4ever]

You should not hear piston slap with any forged piston unless your going with a 2618 material piston. The reason is the 2618 needs more clearance due to the expansion clearance it requires when other types dont need that type of clearance. You run a 2618 piston when your in excess of 800hp and over a 150 shot of NOS or your running 12lbs of boost.

[brickproof]

ok so i know not to use that material when selecting pistons thank you for clueing me in on that. I'm going to start comparing prices for the machine work today when i get a chance.

[brickproof]

iv dropped my engine off at the machine shop with the guy saying he will have a estimate within a week. he pretty much shot down all my ideas, saying to gradually increase my bore instead of going straight to .060 over, he told me to avoid polish/porting heads because it will decrease my torque, and he also said he could have me running a 10 for compression with the right distributor and etc. hopefully this guy knows what he his doing and can actually accomplish what he is saying.