Where to start? Jeep CJ7 with AMC 360

[JEEPCJ360]

Hello All,

Been reading a lot, but this is my first post. A few months ago I purchased a 1978 Jeep CJ7 that has an AMC 360 in it with 15K since a rebuild. Currently it has the following:

- Edelbrock 600 CFM carb with electric choke (no spacer)
- Edelbrock Performer AMC intake manifold
- Stock ignition module (the one installed is made by Wells)
- Stock Distributor with large cap and tall rotor modification
- Engine Bore unknown
- Crank stroke unknown, but most likely stock
- Cam unknown, but the idle says it is most likely NOT stock
- Stock exhaust manifolds to a single exhaust out the rear (no cat)
- No emissions components except for the charcoal vapor cannister
- T150 tranny and Dana 20 t-case.

It starts very easily when cold and is a bit harder to start when warm, but starts after about 4-5 crank revolutions. It idles well and runs strong. The problem is that I have no idea what strong really means because I have nothing to compare it to (unless my 2007 Avalanche counts, but this is like comparing a go-cart to a limo). I have already ordered the HEI dizzy from right hear at Bulltear so I will see if that adds to the performance.

My question is...short of putting the Jeep on a dyno, what is the best way to get a feeling of how close to perfect the engine is running? What I mean by perfect is...am I getting the torque and horsepower out of it that it is designed to produce? I am sorry if this is an odd question, but reading through this forum is a bit overwhelming. I want to steadily improve the Jeeps performance, but I am not a fan of big dollars for small gains if you know what I mean. I like low hanging fruit...YUM!

Any and all comments and suggestions are greatly appreciated.

--Aaron

[Old Rugged Crosser]

If you don't have visions that require uncontrollable horsepower I would suggest that you enjoy it for what it is.--Probably a good reliable 360. Don't go hunting for trouble.

[JEEPCJ360]

If you don't have visions that require uncontrollable horsepower I would suggest that you enjoy it for what it is.--Probably a good reliable 360. Don't go hunting for trouble.

How did you know what my vision was? Are you a mind reader? OK, I don't want uncontrollable power, but I do want controllable power.

[tufcj]

Enjoy it as is for a while, then modify to fit your needs. My 77 has a near stock 360, minor head/valve work, an Edelbrock cam/manifold, EFI (Howell), and a single 3" exhaust. I rock crawl with mine, so gearing and suspension flex is important. I went from the T-150 to a T-18 and swapped the model 20 for a Dana 300. WIth the 4.27 gears in the axles, I have a 70+: 1 crawl ratio. I run about 7" of lift and 37" tires. It could use a bit more gear on the street, but it does great on the trails.

See what you need before you change things.

Bob
tufcj

[Old Rugged Crosser]

How did you know what my vision was? Are you a mind reader? OK, I don't want uncontrollable power, but I do want controllable power.

Hey, calm down, don't get you panties bunched up in a wad. If you will take the time to look at my statement I said "IF YOUR VISION REQUIRED" I'm not pretending to read your mind. Just trying to give you some stellar advice. Take it or leave it. It was free.


Any and all comments and suggestions are greatly appreciated. Apparently it ant so!

[JEEPCJ360]

Hey, calm down, don't get you panties bunched up in a wad. If you will take the time to look at my statement I said "IF YOUR VISION REQUIRED" I'm not pretending to read your mind. Just trying to give you some stellar advice. Take it or leave it. It was free.

Apparently it ant so!

WOW! I don't think I have ever had somebody take a comment so wrongly. I apologize, I was attempting to make a joke. This is the very reason that email and text is so dangerous as a form of communication. If you could have seen my face as I typed it you would have known what I meant. Trust me, there was not a single once of ill will intended in my statement. I am sorry it was taken that way.

[msalaba]

I run pretty much the same setup as you.

360
stock rotating assembly
stock heads w/ recent valve grind
edelbrock performer manifold
summit K8600 cam
edelbrock roller timing chain <- only cause the stock set was shot
stock exhaust manifolds
stock motorcraft dist w/ ford 460 big cap
T-15 w/ D20

Major difference is I'm running propane and have a MSD 6AL ignition.
(added 6al for hotter spark for propane)

Good strong running torquer

Not much else I'd like to do to this engine. Maybe advance the cam timing to get a little more low end power. (seems my torque curve is a little higher than I want)

To your hard start warm issue, check the timing. iirc you want 12* @ 600 RPM vac advance disconnected.

Before you get all gung ho over the HEI dizzy, you may want to search for posts in reference to vac advance can clearance. HEI is convenient but IMHO a POS copared to a motorcraft dizzy. (Pretty bad comming from a chevy guy)

Good luck and let your wallet be your guide!

[msalaba]

Hello All,

Been reading a lot, but this is my first post. A few months ago I purchased a 1978 Jeep CJ7 that has an AMC 360 in it with 15K since a rebuild. Currently it has the following:

- Edelbrock 600 CFM carb with electric choke (no spacer)
- Edelbrock Performer AMC intake manifold
- Stock ignition module (the one installed is made by Wells)
- Stock Distributor with large cap and tall rotor modification
- Engine Bore unknown
- Crank stroke unknown, but most likely stock
- Cam unknown, but the idle says it is most likely NOT stock
- Stock exhaust manifolds to a single exhaust out the rear (no cat)
- No emissions components except for the charcoal vapor cannister
- T150 tranny and Dana 20 t-case.

It starts very easily when cold and is a bit harder to start when warm, but starts after about 4-5 crank revolutions. It idles well and runs strong. The problem is that I have no idea what strong really means because I have nothing to compare it to (unless my 2007 Avalanche counts, but this is like comparing a go-cart to a limo). I have already ordered the HEI dizzy from right hear at Bulltear so I will see if that adds to the performance.

My question is...short of putting the Jeep on a dyno, what is the best way to get a feeling of how close to perfect the engine is running? What I mean by perfect is...am I getting the torque and horsepower out of it that it is designed to produce? I am sorry if this is an odd question, but reading through this forum is a bit overwhelming. I want to steadily improve the Jeeps performance, but I am not a fan of big dollars for small gains if you know what I mean. I like low hanging fruit...YUM!

Any and all comments and suggestions are greatly appreciated.

--Aaron

You have all the "low hanging fruit"

make sure you have 120 - 150 psi even across the cylinders and that you ignition timing is in spec.

Outside of the engine, you may want to look into gearing.
this is really important if you do not have a stock tire size.
many people call their engine a turd when they bolt on 35" tires w/ 2.73:1 gearing

[JEEPCJ360]

Before you get all gung ho over the HEI dizzy, you may want to search for posts in reference to vac advance can clearance. HEI is convenient but IMHO a POS compared to a motorcraft dizzy. (Pretty bad coming from a chevy guy).

Thank you for the thoughts.

I was going to go with the MSD or Summit CDI unit and stick with the Motorcraft dizzy but I have read so many threads on the jeepforum.com site of people having noticeable performance gains with the HEI. I will keep my duraspark/coil/dizzy in case the HEI fails, but I like the simplicity of the HEI. I have not read anything about clearance issues, but I would hope that Bulltear wouldn't sell HEI units that have this issue.

I am running 410 gears so that shouldn't be a problem, right? I will check my timing and see where I am. IIRC i am around 10 BTC right now without vac advanced hooked up. I was a bit more advanced but was getting slight kickback when starting so I retarded it a few degrees.

I think the next upgrade is going to be exhaust. I know you are running stock manifolds, but what are your opinion on headers? Also, what are your thoughts on single versus dual exhaust? Thanks for your time.

[Old Rugged Crosser]

The clearance problem comes in with clearance between the dizzy cap and the power steering pump. If you have that problem like I did, I made a bracket to move the p.s. pump down out of the way. I still have the pattern.

[msalaba]

I think the next upgrade is going to be exhaust. I know you are running stock manifolds, but what are your opinion on headers? Also, what are your thoughts on single versus dual exhaust? Thanks for your time.

My opinion? Headers are for race cars. 111!!!

After listening to the wise sages of this board, there are only two choices for headers. Edelbrock shorties and full custom.

The Headmans are really light construction and hang too low for a Jeep. (had a set and they rotted out) The fenderwell exits may work for a pavement pounder but I would not use them if they salt your roads in winter.

Single exhaust is more suited for low end torque, where duals are more for high rpm. Some of the low torque can can be gained back by putting a balance pipe between the banks behind the engine. This can introduce ground clearence issues if you go off road.

The only reason I'd go duals is racing or if you just have to have the tone (which I did) they are a PITA to route in a CJ frame. My exhaust guy almost fired me! (figure that one out)

On exhaust I'd wait for some of the more knowledgeable ones to comment.

If I were to do it again, I'd go single exhaust and try to find a home for a late GM pickup muffler under my Jeep. I'm just sick of listening to it and I'm running 2 chambered mufflers.

Oh, and stay away from glasspacks, they are proven to reduce power.

[msalaba]

I was going to go with the MSD or Summit CDI unit and stick with the Motorcraft dizzy but I have read so many threads on the jeepforum.com site of people having noticeable performance gains with the HEI. I will keep my duraspark/coil/dizzy in case the HEI fails, but I like the simplicity of the HEI. I have not read anything about clearance issues, but I would hope that Bulltear wouldn't sell HEI units that have this issue.


The issue is not a Bulltear HEI one. It is a physical space limitation on the engine itself. Have you ever seen a GM HEI unit? They are huge and a PITA to work on. They also seem to be hydrophobic. A condition I can't explain.

As to the Motorcraft dizzy issue; if the shaft bushing is wore out it will not hold a stable timing. This is true for all dizzys. The other issue is they tend not to be stable over ~6000 RPM. They are also much easier to tune than a HEI. IIRC, the HEI does not have a mechanical advance limiter, which is only a concern for high RPM usage. The only other downside is the external ignition module. I always carried a spare.

The best part of a Motorcraft Dizzy is they were engineered to fit. The timing curve is also set close to what the engine needs. (70's dizzys)

The only reason to use a MSD billit is for the predictable adjustability. I've worked on these and they are by far the easiset to adjust (versus factory units) thus easy to setup a custom curve. But you pay $$$ for it.

Most likely the power increase you are hearing about is from guys with heavily emmisioned 6 cyl jeeps from the 80's. This was a transitional period where they started to integrate the carb with the ignition. You change the carb and the ignition is thrown off. So, drop in a HEI and OMFG, I got huge HP gains, when all that happened was the timing curve was corrected.

In this society of advertising mania, the OEM gets lost in the shuffle. These engineers, or rather teams of them, spent uncountable hours designing and balancing performance to reliability. Race car stuff does not lean much to the reliable side. It just has to last for a race.



I am running 410 gears so that shouldn't be a problem, right? I will check my timing and see where I am. IIRC i am around 10 BTC right now without vac advanced hooked up. I was a bit more advanced but was getting slight kickback when starting so I retarded it a few degrees.


You did not mention tire size. 4.10's should be good for 35" tires on a D/D. I prefer 4.56 w/ 35" but that leans more to off-road use as the MPG would suck.

Book says 8* @ 800 RPM for timing. I mispoke before as that was 258 w/ auto.
Don't forget to check compression. This can tell you is you have a dead hole or burnt valve. Conditions that cause all sorts of gremlins. If you don't have one, most auto parts stores will loan you one and some for free! :)

My jeep is an stubborn SOB on a cold start (after sitting for many weeks) but pops off in one or two revs warm. This may be cam related.

[JEEPCJ360]

You did not mention tire size. 4.10's should be good for 35" tires on a D/D. I prefer 4.56 w/ 35" but that leans more to off-road use as the MPG would suck.

Thank you so much for your well thought out comments. I truly appreciate your time. I am running the 4.10 gears with 33x12.50R15 BFG ATKO's. So that puts me at about 3000 rpm to do 70 mph.