Another AMC 304 build - JeepForum.com
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post #1 of 23 Old 10-08-2020, 11:08 AM Thread Starter
Ben W
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Another AMC 304 build

Finally getting around to rebuilding my AMC 304 out of my 1977 CJ7. This site has been tremendously helpful in researching my build after I get my machine work done. So here it is, not stunning by any means when I pulled it out.

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post #2 of 23 Old 10-08-2020, 11:10 AM Thread Starter
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I tore down the engine a couple of weeks ago. Upon inspection, everything inside looks pretty good from what I can tell. Cylinder walls were nice and clean, no noticeable wear on the camshaft, lifters, crank, etc. Took it over to the machinist a couple of weeks ago and he is supposed to get started on it today.
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post #3 of 23 Old 10-08-2020, 11:12 AM Thread Starter
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This will be my first engine build. I have been doing a ton of research over the past 9 months, have the FSM, and read through BMannís 304 build thread again last night. Much thanks to Ben for putting the time into that thread. In his thread, I saw where another member had recommended a Lunati cam. I did some research and decided to order the kit which came in last week.

My bigger question that I am trying to figure out is whether to go with fuel injection or upgraded carburetor? My intended use is a weekend warrior, 90% street use. This Jeep has been beat to sh*t most of its life so she will be babied for the rest of it. I researched this and found a thread that was 10 years old. I am thinking there may be newer technology around by today? I compared the cost between and Edelbrock performer air intake and new 700 CFM carb versus the Edelbrock Pro-Flo EFI system and the cost difference was about $800 more for EFI. This may be the only vehicle I rebuild in my lifetime so Iím ok with spending the money if it is worth it. Any advice on this or the best system for my application would be greatly appreciated.

Other than that, I donít have any plans for any further modifications. If anyone has any other suggestions or input I would appreciate that as well. Thanks!
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post #4 of 23 Old 10-08-2020, 05:34 PM
cyates13B
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Quote:
Originally Posted by Ben W View Post
This will be my first engine build. I have been doing a ton of research over the past 9 months, have the FSM, and read through BMannís 304 build thread again last night. Much thanks to Ben for putting the time into that thread. In his thread, I saw where another member had recommended a Lunati cam. I did some research and decided to order the kit which came in last week.

My bigger question that I am trying to figure out is whether to go with fuel injection or upgraded carburetor? My intended use is a weekend warrior, 90% street use. This Jeep has been beat to sh*t most of its life so she will be babied for the rest of it. I researched this and found a thread that was 10 years old. I am thinking there may be newer technology around by today? I compared the cost between and Edelbrock performer air intake and new 700 CFM carb versus the Edelbrock Pro-Flo EFI system and the cost difference was about $800 more for EFI. This may be the only vehicle I rebuild in my lifetime so Iím ok with spending the money if it is worth it. Any advice on this or the best system for my application would be greatly appreciated.

Other than that, I donít have any plans for any further modifications. If anyone has any other suggestions or input I would appreciate that as well. Thanks!

I went with a Holley 350 2bbl carburetor on my 304. Similar use (mainly street with some light off-road travel to fishing spots). I like the responsiveness of that carburetor. I know some folks swear by 4bbl carburetors on V8s; but Iíve been pleased with the 2bbl (also have HEI if that makes a difference).

Iíve not personally seen them on Jeeps; but my father in law uses a Holley EFI on his Impala, and itís pretty impressive. Obviously thereís a fairly significant cost difference between the 2bbl and the EFI.


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post #5 of 23 Old 10-08-2020, 06:27 PM
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It is pretty important that the engine is built to purpose and the components complement that purpose and each other.

There are three basic builds: low RPM, mid range, and high RPM.
Low RPM builds are mild builds that are designed for a mild bump in performance focused on off idle and low RPM increases. They are a mild upgrade from stock and will accept pump gas. They are the best all around DD engines and are least effected by hot and cold weather. Stock exhaust manifolds coupled with dual exhaust, dual plane intakes coupled to small 4BBL carb and a mild cam.

Mid range builds are designed for an increase in the midrange with a bump in the upper end. This is accomplished with with a bump in compression, headers, single plane separate runner intakes, larger carbs, and a mid range cam. The may need higher octane gas, valve train modifications, and can start to be finicky with weather extremes. They can be coupled with stall converters for added launch capabilities. Serviceable DD with the focus more on strip/weekend performance.

High end builds: Large headers/exhaust, high compression, high lift/long duration cam, open plenum/tunnel intakes with large carb(s). Valve train modifications required. Weekend racing and strip use. High octane gas a must. Finicky runners that require more attention than any of the other builds. Work best with modified automatic transmissions.

These are generalities but are accurate.

Builds that use mismatched components are self defeating. Which ever build you choose, be sure all your components are designed for that build.
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post #6 of 23 Old 10-09-2020, 04:48 AM Thread Starter
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Definitely going with the mild build. Camshaft I got is a mild cam, my main question right now if carb or EFI. Thanks.
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post #7 of 23 Old 10-09-2020, 07:07 AM
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I upgraded the 304 in my ‘79 CJ5 this past summer. The 304 had an Edelbrock S.P.2-P 4-Barrel intake and a Holley 4160 carb. Both were about 30 years old and due for replacement. Had oil on intake near bolt heads, carb was leaking fuel and Jeep was very hard to start even if it sat for a day.

I went with an Edelbrock Performer Dual Plane intake model 2131 intake (no EGR) and an Edelbrock 4-Barrel carb model 1901 - 500 cfm. Also purchased an Edelbrock Heat Insulator gasket 9266. Jeep is stock otherwise - stock exhaust manifolds and single exhaust. I did need to lean out the carb a little - about 3/4 turn clockwise on both idle/mixture screws. Make certain to buy a vacuum gauge - link below.

She starts first time every time - I pump the gas pedal once to set the choke and the engine fires. Here are the links from Summit Racing:

http://www.summitracing.com/parts/ed...merican-motors

http://www.summitracing.com/parts/edl-1901

http://www.summitracing.com/parts/edl-9266

http://www.summitracing.com/parts/otc-5613
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post #8 of 23 Old 10-09-2020, 08:06 AM
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I am finishing up an engine rebuild/swap for my 76 CJ5, and I'll add my two cents. My intended use is mostly street/highway and a little offroading a couple times a year...no rock crawling, tough trails, etc.

I just swapped in a 351w and have gone with a mild build. A little taller/longer cam, higher compression, headers, dual plane air gap intake. I rebuilt the same engine years ago and was happy with a carbeurator, but it took a bit of tuning and jet swaps. When it was locked in, it ran perfectly for the couple years I had it before I sold it. With this current build for my CJ, I decided to go EFI. After a lot of research and talking with folks that own different brands, I settled on Holley's Sniper. I chose the Sniper because it self tunes fuel and you can program it. You can also purchase the accompanying Hyperspark ignition box, coil and distributor to control timing...which I did. It's a bit more technical, but you can program a timing curve to improve tuning. It's not necessary, but if you prefer to get into the weeds with tuning like I do, then it's the way to go.

Although there are more wires to run, setup is actually fairly simple. Everything has connectors and you only have to splice a wire or two if you go the Hyperspark route. The other issue is EMI...a lot of folks with Snipers complain of EMI issues when they use their stock or even "protected" plug wires. Folks who have these issues that switch to Magnecor plug wires no longer have problems.

My motor is all ready to go, but I just need to run exhaust...that project is for next week, so I can't report on results just yet.

If you do think about getting the Sniper, I highly recommend looking up EFISystemPro. I spoke with the owner for a few hours on the phone going through what I wanted to do with my rig and he helped me piece together the right system. They have excellent tech support...they helped me through a couple things with install. They also offer tuning review/advice and troubleshooting if you purchase from them...nobody else does that. They also have some great videos on their website on how the Hyperspark stuff works and how to install it. He also had the lowest prices on everything and gave me a nice military discount. Couldn't pass it up.

Hopefully by the end of next week I'll be up and running and I can report back on results.
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post #9 of 23 Old 10-09-2020, 02:42 PM
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I have a 80 CJ5 304, t176 4 speed. I tried and tried to get the carb tuned but could not get it to idle correctly. So I went with the Howell FI kit and haven't regretted that decision. It starts and idles fine even when cold. That stock engine is definitely not a power house, but runs fine for when I want to drive it.
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post #10 of 23 Old 10-09-2020, 08:11 PM
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hello
that is a very nice looking 304 to rebuild. there isnt sludge. on the old engines that mostly ment people actually kept there oil changed with a good oil. the nice thing about a amc block is they used a higher amount of nickel in the iron. so they didnt wear as bad as gm and some others. i always like to keep the oversized bore as small as possible. it just helps with cooling and gives one or two more refresh later.

i saw that you already have a camshaft. nowdays you have to really look at the cam and fuel system more then years ago. before it was to big of carb and to small of cam or vice versa. but now you have to also add in the part of does the cam grind like to play with fuel injection. some systems dont like to play with a cam that doesnt make good vacuum specially at idle. there are pro's and con's for both fuel infection of a carb.

if carb one thing that is important is not to have to big and of throttle bore for a small v8 especially the primaries. as someone mentioned earlier about how your building the engine to run. for a low rpm engine you want smaller throttle bores. the small bores gives more velocity off idle. actually you can get better performance and mileage from a 4 barrel over a 2 barrel if you arent heavy foot. edelbrock which is a new version of carter AFB. there nice because they are a spreadbore where most holleys are 4 of the closer to same size bores. just remember high cfm isnt always better. the more it flows wide open but the velocity of the air is not great at low rpms and plates opening.

oldschool
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post #11 of 23 Old 10-09-2020, 09:14 PM
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The carb I am using is an Edelbrock AVS2 model 1901 ( 500 cfm ). Here is some info about the AVS2:

https://www.edelbrock.com/avs2-carburetors

https://www.edelbrock.com/avs2-500-c...-egr-1901.html
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post #12 of 23 Old 10-14-2020, 04:27 PM Thread Starter
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Quote:
Originally Posted by cglax6 View Post
If you do think about getting the Sniper, I highly recommend looking up EFISystemPro. I spoke with the owner for a few hours on the phone going through what I wanted to do with my rig and he helped me piece together the right system. They have excellent tech support...they helped me through a couple things with install. They also offer tuning review/advice and troubleshooting if you purchase from them...nobody else does that.

Appreciate the advice, I will definitely check them out.
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post #13 of 23 Old 10-14-2020, 04:28 PM Thread Starter
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Quote:
Originally Posted by Hurricane4 View Post
The carb I am using is an Edelbrock AVS2 model 1901 ( 500 cfm ). Here is some info about the AVS2:

https://www.edelbrock.com/avs2-carburetors

https://www.edelbrock.com/avs2-500-c...-egr-1901.html


Hurricane, thank you for all your input. I am going to look into these as well.
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post #14 of 23 Old 10-14-2020, 04:32 PM Thread Starter
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So I heard back from the machinist the other day and he told me that the cylinders needed to be bored .030 over. I thought that sounded a little much but I didnít want to question him. Does that sound right or should go back and ask the question? I donít believe he has done the work yet but was going to order the pistons which I imagine could be returned if needed.
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post #15 of 23 Old 10-14-2020, 04:44 PM
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Quote:
Originally Posted by Ben W View Post
So I heard back from the machinist the other day and he told me that the cylinders needed to be bored .030 over. I thought that sounded a little much but I didnít want to question him. Does that sound right or should go back and ask the question? I donít believe he has done the work yet but was going to order the pistons which I imagine could be returned if needed.

Iíve only personally done one 304 rebuild; but that doesnít sound too over the top, from what me and a few others have had done. My 304 had to be bored over a bit more than that (.040 IIRC) because a couple of the cylinders had a little more wear on them.


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