4.2 with 4.0 head or stroker?

tower210

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Olathe
State
KS
#41
Will it hold speed on the highway? I don't care about power above 4k rpms. I just want to make good and sure that I have enough power to go down the highway.
My stock 4.0/4.56 gears/ 295/70/17 will do 75 on the highway.....not much more; but I fell that’s plenty. I ride 90 minutes each way to my local orp.... little rough with mud caked wheels on the way home
 

CJ-8_Jim

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
NW Chicago Suburb
State
IL
#42
Will it hold speed on the highway? I don't care about power above 4k rpms. I just want to make good and sure that I have enough power to go down the highway.
With 2.73 gears and 31s I easily do the legal max highway speed... I never go over the limit, so I wouldn't know what my budget stroker can comfortably cruise at above that. :unsure:
 
Last edited:

BDCCLARK

Member
LIFETIME
City
gravois mills
State
MO
#43
I'm not worried so much about top speed. I just don't appreciate under powered engines. The whole idea seems like an engineering mistake to me. I want to make sure my jeep will hold highway speeds in overdrive. Heck, I wouldn't even bother messing with a swap if I knew a 258 would do it. From what I read, I'm not so sure it won't. It seems to me that one of the major drawbacks to a solid running 258 is the stock ignition curve in the distributor. I see many people putting efi on and love the improvement in power and drivability. I'm betting that it has way more to do with the computer controlled spark curve.
 

YJ-8

Basic User
City
Austin
State
TX
#44
Will it hold speed on the highway? I don't care about power above 4k rpms. I just want to make good and sure that I have enough power to go down the highway.
Yes, when I had 31" tires and 3.73 gears it had no problem holding speed, it is solid. 5 speed manual, you could chirp the tires shifting 1-2 and once I chirped it going into 3. It will hold 70 no problem, it will hit 80, but its happy place is 30-60, so IDK how fast it will technically go. Fastest I ever hit in it was 95 mph (stock engine) and did not find it very fun, its a Jeep.

Now that I have 35's with the same 3.73 it has trouble on long mountain passes.

FYI: when it was stock (carter BBD carb) it could not hold highway speed if the wind was blowing against you, it was a dog.

All this said, its no modern V8. I drove a 6.0 Caddy Escalade and it would hold 80 up a mtn pass like it was flat, and that weighs 2,000lbs more than my Jeep. It would be nice in a CJ.
 

BDCCLARK

Member
LIFETIME
City
gravois mills
State
MO
#45
Yes, when I had 31" tires and 3.73 gears it had no problem holding speed, it is solid. 5 speed manual, you could chirp the tires shifting 1-2 and once I chirped it going into 3. It will hold 70 no problem, it will hit 80, but its happy place is 30-60, so IDK how fast it will technically go. Fastest I ever hit in it was 95 mph (stock engine) and did not find it very fun, its a Jeep.

Now that I have 35's with the same 3.73 it has trouble on long mountain passes.

FYI: when it was stock (carter BBD carb) it could not hold highway speed if the wind was blowing against you, it was a dog.

All this said, its no modern V8. I drove a 6.0 Caddy Escalade and it would hold 80 up a mtn pass like it was flat, and that weighs 2,000lbs more than my Jeep. It would be nice in a CJ.
Thanks for the reply YJ-8. I'm gonna give the inline 6 a whirl. The higher rpm engines are great for sure, but I love the low end pulling 6s.
Chris
 

YJ-8

Basic User
City
Austin
State
TX
#46
Thanks for the reply YJ-8. I'm gonna give the inline 6 a whirl. The higher rpm engines are great for sure, but I love the low end pulling 6s.
Chris

I think you will be impressed how stout a good running I-6 can be, It can surprise you. I also think they have charm.
You can PM me and I will give you all the specs I have on mine.

YJ-8
 
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