a few stroker questions

[89 Sport]

OK, I know this is a little different then other stroker questions. I was contacted from a guy in town with a CJ, 258, man. Im thinking its an 85 maybe 86 who is looking to have it restored. Thats not a problem we have done this in the past. He wants more torque out of the 258. So, I was thinking about putting a 4.0 in it with stroker parts in it He would rather go without F/I so it looks STOCK (thats a hoot because he already has a glass tub and a ton of other after market parts). Ill be doing some searching on my own regarding this but I am looking for as much input as I can digest. Getting this job would free up some cash around here so I can get back to my projects and since he has 2 other parts cj's I might get lucky and get some stroker parts for my xj . .

How do these strokers run being carbed?

Would we be able to expect the same or maybe a little more performance because of the lack of smog equipment?

If I stick a 4 bbl. on it, what cfm's would be best suited for this motor?

What head should be used?

 

[NorCalChris]

No offense, but if you can't calculate needed cfm you probably shouldn't be charging to do a motor build. Just my opinion.

 

[89 Sport]

I am NOT a motor builder. If I was I would not have asked any questions about building a motor. I know enough about the subject to comprehend what I am told. I want to be able to talk to the builder about what he is building. In the end its my A$$ and reputation on the line. So because I cant (and dont want to) set up gears I shouldnt get paid when I install the diffs.? If I am restoring a car should I not be paid for my time? Would you install a motor for free. I wouldnt expect you to. I am asking here on naxja because I have been around here awhile and I know there is a lot of info here and there are people here that know thier $h!T. With some discussion I can get ideas and therefore learn something in the process.
I have to give you a thanks for the quick reply and :flame:. Oops I just saw your sig. How many pizzas should I charge for a motor install. LOL.

 

[89 Sport]

I am NOT a motor builder. If I was I would not have asked any questions about building a motor. I know enough about the subject to comprehend what I am told. I want to be able to talk to the builder about what he is building. I am trying to figure out what the volume efficiency is. If I knew that I wouldnt have to ask for help. In the end its my A$$ and reputation on the line. So because I cant (and dont want to) set up gears I shouldnt get paid when I install the diffs.? If I am restoring a car should I not be paid for my time? Would you install a motor for free. I wouldnt expect you to. I am asking here on naxja because I have been around here awhile and I know there is a lot of info here and there are people here that know thier $h!T. With some discussion I can get ideas and therefore learn something in the process.
I have to give you a thanks for the quick reply and :flame:. Oops I just saw your sig. How many pizzas should I charge for a motor install. LOL.

 

[4.whoa]

Just my opinion but a 4bbl doesn't look stock either. Way back when I was thinking of building one, I was planning to get a Clifford intake and run a 4bbl on my 7120 head, but I was looking for more strip than street.

 

[89 Sport]

Yea I know. But its closer then stock then f/i. He likes the simplicity of a carbed engine because it would be something he can wrench on himself if he has to. He wont be doing much wheeling just something to get around his land with (farmland) while hunting and short trips around town. He is an older gentleman and he hunts from his 63 Ford PU now and he is wanting something that would give him more room to use a crossbow or shotgun from. I sugested the stroker route to him and he liked the idea. out. Probably have to use the 4.0 pulley system and get an a/c delete or give it oba, I doubt that he will ever need it but ya never know.

 

[Dr. Dyno]

How do these strokers run being carbed?

Would we be able to expect the same or maybe a little more performance because of the lack of smog equipment?

If I stick a 4 bbl. on it, what cfm's would be best suited for this motor?

What head should be used?

If you're going to build a 4.6L stroker using the crank & rods from the 258, you'll want to use the 4.0L head for best performance.
The '99+ curved runner 4.0L intake manifold would be a good candidate to adapt for a 4-bbl carb. By my calculations a 280ci stroker with a 5200rpm rev limit and an 85% VE will require 358cfm of air so you'll need to be looking for a 390cfm Holley or Edelbrock carb.

 

[89 Sport]

Thanks doc. I was waiting for you to chime in. One more question if you dont mind. Will the performance gains be the same with a carbed engine?

 

[Johnnie Walker]

Thanks doc. I was waiting for you to chime in. One more question if you dont mind. Will the performance gains be the same with a carbed engine?

Carb setup will never be able to be as finely tuned as EFI. However, you will definitely see improvement. Heck, Even swapping a good running 4.0L with a carb setup would net you more.

 

[89 Sport]

Thanks!

 

[Dr. Dyno]

EFI offers better gas mileage, driveability, and emissions than a carbed set-up and probably offers a better spread of torque. That said, a carb does offer simplicity and if set up correctly, can still perform very well.

 

[yossarian19]

F1 abandoned carbs and NASCAR abandoned carbs. So has every automaker - decades ago. Just sayin' - it's a big step backwards in reliability, drivability, emissions, mpg, probably power / torque too.

 

[Dr. Dyno]

Agree 100% except for the reliability part. I grant that you won't need to frequently tinker with EFI but it does have a lot of sensors so there's more potential for a malfunction, and failure of certain sensors could leave your vehicle dead in the water with the engine refusing to start.

 

[O-Gauge Steamer]

This is all very true. An EFI engine is far more complicated than a simple carb'd engine. But, it is the very complications that deliver the drivability and fuel economy. Carb'd engines have no idea what the AFR is and go out of tune as a rule whereas an EFI engine corrects itself during running.

I can say, from looking at the code that operates our PCMs, that the level of control over the AFR is light years ahead of any carburetor out there.

Mind you, I was a major supporter of both Dellorto and Weber carburetors when they were the "state of the art" This is true no longer. By contrast, there is not a single American built carb that is in the same league as these. Both manufacturers provided main jets, intermediate jets and some of them had "emulsion tubes" to get a handle on the mid range performance.

Most American carburetors have main jets and those jets are expected to provide fuel, in the proper ratio, throughout the rpm/load range. This is, obviously, impossible.

If you all could see the amount of code dedicated to fuel and ignition management in our PCMs, you would, I believe, change your opinion.

 

[Root Moose]

In thirty years of driving EFI vehicles I've never had an EFI issue strand me at the side of the road - and that includes some crufty old crap that had no rights being on public roads.

Carb'ed vehicles... yeah, don't go there.

Seriously, put all new sensors and crap on the built engine and the guy will likely be dead and buried before that part of the engine has issues.

2¢