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post #1 of (permalink) Old 05-30-2002, 05:16 PM
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304 buildup

well, i took my block and heads to the shop yesterday, and we've come up with a gameplan. we're probably going with chevy 305 pistons, since the block was previously bored .030 by the previous owner. he used low quality pistons and overheated the engine so we'll have to make up for his mistakes and bore .026 over, which will fit a 305 piston sized for a .060 over bore. this swap will be fairly easy, it requires boring or relocating the wrist pins. the connecting rods will be the stock AMC. if i can find an intake manifold gasket thats not a valley pan style. we can deck the block and machine the top of the block to the point where itll still fit the intake. the compression ratio should come out to 9.5:1. im going with an edelbrock performer plus cam to go with my intake and 600 cfm carb. (yeah i know 600 is a little overkill for a 304, but after this engine is done it wont be.) heddman headers and purple hornie sidepipes will top off the process. im thinkin ill actually have a powerful 304 when im done, who said you cant polish a turd? ill post buildup pics as i progress -- Andy
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post #2 of (permalink) Old 05-30-2002, 05:37 PM
 
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Re: 304 buildup

thats pretty neat and all, but WHY?

is the machinest your pal, giving you a price break or something? I cant imagine doing that kind of custom work on a 304, heck I dont think Id pop the coin on a 360 or 401 !

its pretty neat tho!

give us some dyno slips when its done!

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post #3 of (permalink) Old 05-30-2002, 05:52 PM
 
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Re: 304 buildup

I have to agree, you are polishing a turd!
That probably wonít be popular with the purists but if you are paying retail for this work you probably would miles ahead to build, at the very least, an AMC 360, which will bolt right in place of the 304. I built my 360 stock and I am completely satisfied with the power.
If your machinist isnít charging you much, you could take the money you are saving and buy a 360, they are cheap and plentiful and you will be much more happy with the results.
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post #4 of (permalink) Old 05-30-2002, 06:13 PM
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Re: 304 buildup

well i mean i know its a 304 and it basically sucks, but its what i have and i dont know if a 360 would be that much better, i mean maybe it would be, but im not really made of money, plus this is serious downtime to my daily driver. but then again, if i were to find a 360 with a good price, who knows. the machinist isnt really my buddy, i mean were cool and all, and he said he appreciated getting to talk to a guy who actually knows his stuff. so no price break, but real cool guy. im just not sure on the 360 thing, itd be diff. if i had one on hand
post #5 of (permalink) Old 05-30-2002, 08:29 PM
 
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Re: 304 buildup

I would suggest going with the 360 as well.. I'm in the process of this myself.. Find an 87 waggie that is kinda beat up and get it for cheap.. You now have a 360 (minus the fly wheel if it's an auto) and you now also have a dana 44 front and rear.. You won't be able to use the front, but might be able to part it out, but you can use the rear... some of the mid 80 waggies also came with the HD AMC 20 rear axel..

I would do a little more research about the 360 and parts that you could part out from the doner vehice.. You may find that it won't cost you very much... Apparently the 360 works very well with a 4 barrel on it too [img]images/icons/smile.gif[/img] ...
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post #6 of (permalink) Old 06-01-2002, 01:15 AM
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Re: 304 buildup

alright guys after much consideration, im going with the 304. not b/c its the best (haha no WAY thats the case) BUT i am convinced i can make it into a very good motor. many have tried, many have failed, but i like to be a little different and innovative so im goin for it. i think ill be pleasently suprized at what i can get out of this motor. with the 305 high compression pistons, the decked block,cam, redirecting the oil flow ( drilling and plumbing the lifter valley to direct more oil to the often starved rear main bearing) and a little time and money, i think it can be done. call me different, call me crazy but im gonna do it and it will be done right! i have almost completed sanding down and painting my axles and frame, and ill get some pics asap, probably tomorrow. as for the engine color scheme, im gonna go with dark primer grey for the block ( to match the frame and firewall i just painted), dark primer for all the bracketry etc.., as well as for the vaulve covers. the standout will be the heads and air cleaner housing which will be chevy orange. yeah i know color isnt the important factor at this stage, but what the hell, it gives me somethin to do and think about while the block is in the shop. for a peek into the future, my fall project is going to be a waggy d44 rear with 4.10's and an ox locker, and 31 spline shafts, and either a waggy or scout front axle with 4.10's and chevy flat top knuckles to do a high clearance steering setup to accomodate the spring over i will be doing also in the fall, with cj 7 rear leafs all around. 36x14.50 tsl's on 15x10 black rockcrawlers will round off the project. thanks for listening to my rambling, and let me know what you think -- Andy PS -- tf727 swap in place of tf999 will also be done this fall
post #7 of (permalink) Old 06-01-2002, 12:45 PM
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Re: 304 buildup

The 304 is not that bad of an engine. I had one that was swapped for the 360. The 360 gets about 5mpg less than the 304 did so it has advantages. The 304 also made plenty of power for me, I just had bigger in a parts truck and went with it.
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post #8 of (permalink) Old 06-01-2002, 01:04 PM
 
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Re: 304 buildup

a question.... why do the high-compression thing on a low rpm torquey truck motor that sees off-road duty and hills? With the lower 8.5:1, it will start easy, have no trouble with carbs, use cheap gas, no timing issues, no overheating issues, plenty of bottom-end torque, and idle all day long.

Once you start getting above 9:1 with a carb, count on premium gas if you don't want to ping and have to retard the timing till it won't move. Higher compression = hard to start when hot, overheats easy, and takes expensive gas.

Then add a high performance cam and a big carb and you are talking an engine that loads up and fouls plugs at idle and stalls every time you touch the pedal or try to climb a hill. That is great if you run in the mud and you won't see less than 3500 rpm, but for a daily driver/ general use 4x4 -- no way.

Why not go with what works and is tried and true for a truck: stock nice low truck compression ratio, flat top pistons, RV cam, 2-bbl non-emissions carb, RV headers, high volume oil pump. Maybe even consider a stroker kit. Then you will have all the low-end grunt (idle - 4,000 RPM) in the world and decent fuel economy. Those have plenty of vacuum at idle and have no trouble climbing steep stuff.

Just my opinion.....

Regards

John
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post #9 of (permalink) Old 06-03-2002, 05:27 PM
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Re: 304 buildup

john -- i am not going over 9 to 1 compression, they dont make flat top 304 pistons, and i wouldnt think with 9 to 1 itd be any harder to start. i am advancing the cam timing 4 degrees to make more low end power available, but as long as i dont go over 9 to 1, you think ill be ok? ive never heard moderately high compression pointed out as a bad thing, i mean most v8's got higher compression from the factory than amc's, ive always heard 8.4 is too low.
post #10 of (permalink) Old 06-03-2002, 10:17 PM
 
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Re: 304 buildup

"the compression ratio should come out to 9.5:1. im going with an edelbrock performer plus cam to go with my intake and 600 cfm carb"

I see that since then, things have changed a little. Under 9:1 is more managable for a street vehicle. I would still aim back down below 8.7 for a Jeep that sees off-road.

I had an old 4x4 pickup truck with a 11.5:1 compression big block Police Interceptor engine swapped into it. Boy, would that thing go, but don't ever try to pull a load with it. It was almost worthless as a 4x4. It didn't even run right with premium gas unless I added like 5 bottles of STP octane booster every time I filled up.

The things to pay attention to when you compare compression specs is the year they were made and the type of vehicle they were in.

69-72 were the highest compression engines we have ever put on the street. They were like 10.5-12.5:1 -- but only in cars. Those engines needed high lead 100-110 octane to run right. Heavy truck engines stayed around 7:1-8:1. Pick up truck engines (even in the late 60's and early 70's) never usually went above 8.5:1. Take a look at the old school bus, heavy duty truck, pickup truck, and Jeep stock engines. They were made to be beasts of burden, to pull everything in the world, and to be dead reliable.

Once fuel emissons hit, the compression ratios quickly dropped to 8:1 - 8.5:1. Almost every car and light truck engine in America from the mid 70's through now is built with compression around 8.5:1 because:
1. lower cylinder temps make emissions more managable
2. unleaded gas burns much hotter, pings, and melts pistons with higher compression.
3. For carbs to be trouble free and easy to live with, you need lots of room for error.
4. It just works well.

My opinion: A carbed Jeep that will see lots of low rpms (idle - 4000), 8.5:1 is about ideal. It just makes it so much easier on you when it comes time for carb jetting and timing setting with regular unleaded pump gas.

Of course, the thing to remember is that it is your Jeep, not mine. You are the one writing the check, so you gotta be happy with what you are getting. Whatever you decide to do with it, enjoy it. New Jeeps don't have V-8's, and I am jealous.

Good luck with the build up.

Regards

John
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