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Thread: the first 304

  1. #1
    Join Date
    Mar 2007
    Location
    b'ham
    Posts
    15

    Default the first 304

    I just bought a 304 2v. I was told the motor came out of a 1970 javelin, and It was the orig. Is this possible? I thougt 72 was the first year. If so, does it have more horse power?
    2nd. question. Did the lower end on 304, 360, and 390 come from the same block? are the heads similar?

    3rd. question. What cfm are factory 2 barrels. could I use a 500 cfm w/ a short header set up?

    I would like to stay with a 304, and I think I can get enough h.p. using it. But I would like to know if any one has hot rodded one, and what they did. I dont want a drag racer, I am going for scca type road machine.

  2. #2

    Smile 304's and the such

    Quote Originally Posted by bp2800
    I just bought a 304 2v. I was told the motor came out of a 1970 javelin, and It was the orig. Is this possible? I thougt 72 was the first year. If so, does it have more horse power?
    2nd. question. Did the lower end on 304, 360, and 390 come from the same block? are the heads similar?

    3rd. question. What cfm are factory 2 barrels. could I use a 500 cfm w/ a short header set up?

    I would like to stay with a 304, and I think I can get enough h.p. using it. But I would like to know if any one has hot rodded one, and what they did. I dont want a drag racer, I am going for scca type road machine.
    The first year of the 304 was in 1970. This was a upgraded motor from the 290 which was produced from 67-69. The 70 304 has a few more ponies than the later model 71-78 (the last year I do not recall, they were used in Jeeps but I do not know the last year that they were used). Also the 70 motors had smaller combustion chambers which would increase the horsepower of the engines. The draw back to these motors are the smaller valves that were used in the heads than the 360, 390, and 401 engines. So in essence the valve train in these heads are somewhat inferior to the larger engines. The bottom end in these motors (304) were not re-enforced like the 390 or 401 blocks and with any engine is prone to breakage at higher sustained RPMs. My advice is go to at least a 360 block for endurance and the larger valves. The 304s were good engines for the use that they were designed for, but not very good for racing purposes without major modifications. I do know of a person who put nitrous on his 304 along with some larger valves and the engine produced some decent horsepower, but he probably spent more money on that motor than if he would have built a good 360 or 401. If you upgrade to a larger motor, keep your heads and have them built for the larger valves. These heads to some collectors are the cat meow for they are of the smaller combustion chambers and thus higher compression and horsepower.
    I have in the past converted the 2 BBL factory setup to that of the 4 BBL on 304s with various degrees of success. I took an Edelbrock 4 BBL and jetted down to about 2 or 3 sizes smaller and got some result. Since the valves are smaller and the such, the CFM of the carb had to be adjusted. I would look into a larger 2 BBL such as Holleys or Carters.

  3. #3
    Join Date
    Mar 2007
    Location
    b'ham
    Posts
    15

    Default

    Thanks for the tip, I found the motor by chance and Javelins are very rare in Alabama. So i will have to get a 360/390 out of a Jeep. Will a AMC jeep motor have other needs I will need to be aware of?

  4. #4

    Default Jeep Drop ins

    To the best of my knowledge, there is no modifications needed to drop a Jeep V-8 AMC motor into a passenger car. I recently took a 401 that came out of a Jeep Wagoneer and drop it into my Javelin. No muss, no mess. I do not believe that you could get a 390 in a Jeep vehicle since AMC did not buy Jeep until 1971. Up to that time, I do not believe that Jeep had a V-8 that was used however I could be in error.

  5. #5
    Join Date
    Feb 2006
    Location
    victorville,CA
    Posts
    172

    Default

    one other thing to remember is the 70-71 motors had the crankshaft end made to accept the borg-warner automatic(nub on front of torque converter).as to 72-up,you are ok with any torque-flite trans amc used fom 72 on up

  6. #6
    Join Date
    Oct 2007
    Location
    Fort Wayne, Indiana
    Posts
    2

    Default

    Quote Originally Posted by donsjave
    To the best of my knowledge, there is no modifications needed to drop a Jeep V-8 AMC motor into a passenger car. I recently took a 401 that came out of a Jeep Wagoneer and drop it into my Javelin. No muss, no mess. I do not believe that you could get a 390 in a Jeep vehicle since AMC did not buy Jeep until 1971. Up to that time, I do not believe that Jeep had a V-8 that was used however I could be in error.
    A 390 V8 was never installed into any Jeep product.
    Only a couple of years was 304 installed into Full Sized Jeeps.
    I've only heard about a 304 in a J10.
    The standard powerplant for FSJ were the 258 I6, 360 V8 and 401 V8.
    In Baby Jeeps, CJs, the only V8 was the 304.
    Bryan Smith
    2004 KIA Optima (wife 's DD)
    1999 Jeep Grand Cherokee Limited (my DD and I hate it!)
    1986 Grand Wagoneer (currently stored, but has turned into a 6.2L Diesel repower project! )
    1981 J20 ex-USMC Stock with a super kewl commercial flat bed
    1993 GMC Vandura 3500 (6.2L Diesel Donor)

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