Guys/Gals, I am a novice and need some help. Here's my story. I have a beautiful 83 CJ7. I am putting a 304 in it. I bought a 304 and am going to send it to the remanufacture shop. I am going to have them put the engine together for me. What I mean is I am asking them to put the intake manifold and carbuerator on also. The 258 I have in there now has no egr stuff on it. I am running electric to the HEI distributor and all the other computer stuff is gone. I want to do the same on my 304. Can I just get a non egr intake (Edelbrock Perfromer) and then I am good to go with just a carbuerator?
What kind of carb do you all suggest and should I go with what the engine rebuild guys called a "towing" cam that gives more horsepower and more torque?
This is the way I see it going. I get the engine rebuilt and assembled with a non egr manifold, HEI distributor, and a new carb. I get my transmission rebuilt while it is out (it's a 3 speed auto) I put the whole thing back together with some new mounts, headers and dual exhaust. I am looking for about 250 horsepower.
Thanks for listening and I would really appreciate a reply from some of you experienced folks. I hope to be experienced myself soon.
Don't know what the emissions laws or pending emissions laws are in Michigan, but that'd be the first thing I check. I had an aftermarket intake with no EGR/CTO and a non-OEM carb and thought I was good, she ran like a champ. A year later, northern CO passed higher emissions standards and, while it may have passed a sniffer test, it would never pass a visual. Had to undo all of my work and toss on fuel injection. Food for thought.
I would suggest going with at least a 600cfm 4 barrel especially if you go with the bigger cam. My step dad put a big cam in his 304 and his 500cfm wouldnt quite do it.The 304 is a relatively low horsepower engine out of the box (rough shot i would say maybe 150hp) now the intake, carb, cam, HEI, and headers will all be a big bonus for the 304, but i dont think shes gonna push out 250. Not to mention and you probably already know that AMC motors are expensive and the part stores never have parts in stock. if your looking for an easy 250 hp, put a small block 350 with the same upgrades. Parts are cheaper, always in stock and its a much stronger engine out of the box. but if you still want to keep it somewhat "original" and want the 250hp i would suggest looking into a 360 or even a 401 AMC and go from there..(This is only my opinion of corse).
have the shop pay real close attention to the oil pump portion of the timing cover for wear and grooves etc. Depending on your budget, consider using Bulltear's complete assy. Little spendy but a lot to be said for 45# @ 600 rpm idle and 65# at anything over that, hot.
Also get your heads "pressure tested" before they start working on 'em. I had 1 cracked and they are a little hard to come by.
Remember to buy a new flywheel flex plate. 6 won't work. Harmonic balancer won't either. Summit has billet ones reasonable.
Finally assemble it w/ GMB HiFlow water pump. (Advance Auto).
If it's good TO you, it's gotta be good FOR you....
Torque & 'Towing' package camshafts usually require carbs and header tubes on the SMALL SIDE, and usually use 'Y' pipe and single exhaust...
If this is going to be 'Street Driven', the slightly smaller carb and exhaust will limit your 'Horse Power' a little,
but unless you are replacing the factory cast iron rods with some stronger steel rods and having everything balanced,
Then it works in your favor anyway, you won't be getting about 5,000 RPM anyway, so you aren't loosing anything...
MAKE SURE YOUR SHOP KNOWS ABOUT CHECKING FOR 'Slag' or 'Overcast' in the top timing chain sprocket!
Not many AMC builders out there, and they keep missing the 'Casting Flash' in the oiling passage of that top sprocket.
With a Performer intake, stick with about 1-1/2" to 1-5/8" header tubes with fairly long primary tubes and don't get stupid with the collector/tail pipe size...
This will give you a LOT of torque, you will sacrifice only the RPM range you CAN'T USE ANYWAY, so it's no sacrifice at all really...
Thanks for the repy. The purpose of the vehicle is street (show) 90 % and light off-road 10%. If I understand you correctly I think you are saying I should stick with a "normal" or "stock" cam and still go with the Edelbrock 2131 and a 600 cfm carb. Along with headers and a HEI I should have plenty of power for what I want to do with this jeep?
I live in Michigan and there is no smog controls here so do you beleive the total abandonment of the EGR is acceptable? I have no choice anyway because all the computer stuff is gone.
My rebuild shop is very well respected around town (Grand Rapids) so I will be sure and mention to them about the "slag" in the chain sprocket. Is this an oil restriction thing?
Do you know if my power steering pump from my current 258 will still work?
SLAG in the oil passage in the top sprocket is the #1 reason fuel pump eccentrics, distributor/camshaft gears fail, and timing chains stretch/erode.
For some reason, many engine builders MISS that passage and don't check it...
Probably because there aren't a lot of AMC engines getting built these days!
EGR on a 'Show' vehicle is a waste of time.
EGR will help you with 'Cold Starts', but show vehicles don't get started and have to run DAILY in the winter, and they are NEVER left outdoors where the worst of the winter can eat on them...
The 'Stock' camshaft is going to produce 'Stock' results for torque and horsepower, so that's NOT what I'm saying at all.
A mild 'Street' cam, or a 'Torque & Tow' camshaft would do you a better job in your situation.
What I'm saying is,
DO NOT get stupid on the exhaust size, fastest way to kill any potential fuel economy or torque building.
And since the engine is pretty much 'Stock' on the lower end, you don't want to break about 5,000 for a rev limit or you will have holes in the oil pan from the inside using factory cast iron rods...
The 'Larger' the camshaft you use, the higher up in the RPM range you will have to reach to achieve the power ratings for that camshaft...
Since you CAN NOT reach way up into the RPM range,
You are better off with a MILD CAM that makes good power lower in the RPM range,
And that will require smaller exhaust & intake, carb, ect.
Which is all good news since the smaller stuff is usually cheaper also...
On a 304 engine, the 'Performer' is going to run about of intake runner size about 4,000 RPM, Just flat won't make any power past that point, so it's about perfect.
A reasonable size carb will feed a smaller engine, and give you better throttle control, and that will give you better fuel mileage & driveability.
Reasonable size header tubes will keep the 'Overlap' in the camshaft from allowing your fuel/air mixture from getting 'Scavenged' or 'Sucked' out of the combustion chamber,
So that means increased fuel mileage and power.
DO NOT let anyone talk you into larger than a 650 carb, and around 550 or so would be MUCH better for a 304.
DO NOT let anyone talk you into larger than a Performer carb (NOT THE RPM VERSION!),
EGR is your choice, it's an ugly spot for a 'Show' vehicle, but it does help with cold starts and emissions.
DO NOT let anyone talk you into 1-3/4" or 2" header tubes! WAY TOO BIG and will scavenge the incoming fuel air mixture out of your cylinders on that particular little engine.
Longer primary tube headers make more TORQUE,
While shorter primary tubes make more horsepower.
Torque is what gets you moving, presses you back in the seat.
Horsepower is a byproduct of torque...
And since you are NEVER going to build a 304 with factory rods to make any real horsepower, might as well go for a good torque curve and a reasonable gear ratio for the street...
The taller your tires, the 'Deeper' you need the gears to be for the engine to work well in the vehicle...
Even 'Torque' cams need to be around 2,500 RPM to make much of any real power, so the deeper your gears, the faster you reach the engine efficiency RPM zone.
I've more or less gotten away from camshaft recommendations on here because most guys end up going with some "rv" cam that their machine shop recommended and it's usually some old re-packaged Melling grind from the '60s that has too much seat duration, too little duration at .050, too little total lift and too wide of a LSA to make any torque worthy of note.
This is probably the cam I'd select for what you're doing. http://www.compcams.com/Company/CC/c...x?csid=20&sb=2 Modern cam profiles make more torque and horsepower with less duration, better manners and more manifold vacuum than any of those older "rv" cams ever could.
As was already mentioned, the regular old Performer intake, 600 cfm carb is plenty and long-tube headers with no larger than 1 5/8 primarys and hopefully only a 2.5 inch collector. I'd stay away from 3 inch collectors.
Go for it
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What Swanson said about camshafts.
I can't really get into lift, duration, duration at lift, ect. since you loose EVERYBODY when you do that...
He's right about the 'Torque' cams, they usually don't get the valve open soon enough to suit me, and they don't keep the valve open long enough to suit me...
And since we don't 'TOW' or are running them in big, heavy RVs, they are really not fitting the application very well, but it was the ONLY alternative for many years.
Figure out what RPM range you are going to run, find a camshaft that works in that RPM range, and keep things REASONABLE if that RPM range is reasonable...
Edelbrock has a reasonable camshaft that works well with stock heads, just remember to use the correct spring/lifter package with that camshaft, and keep the intake/exhaust reasonable.
If you use the camshaft Swanson recommends, use the springs/lifters Holley/Comp Cams recommends and you will be fine.
When they give a big range of engine displacements like 290 to 401, remember, the smaller the engine, the 'Lumpier' the cam will seem, in a small engine it might 'Lope' a little,
While a larger displacement engine will tame that camshaft down a little...
Don't get too stupid large on a camshaft, or you will have vacuum issues and you won't get into it's operating range, while if you go too small on the camshaft, you won't make torque or horsepower...
Big cams need a LOT of seat pressure (Springs) to get the valve train to follow the camshaft lobe, so you wind up with problems with spring bind if you don't cut the heads for the larger springs,
And hammering valves on the seats when the lobe drops out from under lifter and the valve spring slams the valves shut,
So something that will install in stock heads is usually best and lives longer...
What's supposed to be there, anyway.
Ouch! There's another set-up that would require a custom grind for optimum results.
Based on your header thread, if you aren't able to find the right headers and are forced to use exhaust manifolds, this is the cam I'd go with. It has thirteen degrees less overlap which will help you not screw up your intake manifold vacuum.