HP at 2500RPM and below, is a stroker worth it?
Posted: January 23rd, 2022, 12:34 pm
Hi all,
It is time to rebuild my 258 and I am contemplating several options. I have some questions and my intent is not to bash anything. I am just looking at numbers, understanding how I drive my Jeep and being realistic. The options I can do are: 258 stock build, bolt on a 4.0L head to the 258, build a full 4.6L stroker, of swap in a V8.
My goal is not to make massive HP, but would like a little bump for highway power for mountain passes over the Sierra Nevada would be nice if I could. When I drive I tend to keep her at or under 2500 rpm, and drive 60mph max (I am realistic with a CJ7). I have installed the Howell TBI on her and that works wonderfully and would like to keep that. With the NP435 I installed, she just pulls up mountain hills at slow spends wonderfully. But at 60 mph through the Sierra Nevada freeways/highways. well....here I am looking for solutions.
So I can do:
1. A V8 swap. But this options just seems to costly and more work than I really want to do, but it is not off the table yet. It will yield the biggest difference, but at a cost that is not attractive.
2. A 4.6L stroker. I know they make impressive HP, but at rpms I never achieve. This has me thinking that it may be pointless to build for what I am looking for. I rarely see HP/Torque number below 3000rpm. I did see one 4.6L stroker build HP/Torque printout that was at 2500-5000rpm. At 2500 rpm the HP was better than my 258, but it was way less than I thought it should be considering the extra cost to get a new complete engine. This is not a bash, please do not mistake. It just seems more costly for little, if any, gains at 2500rpm and below. Cheaper than a V8 swap, more than a 258 rebuild, unsure if the gains I could use.
3. Add the 4.0L head to my 258. I know the head has is more efficient flowing and has a better combustion chamber design. The 4.0L head design chamber will deter spark knock that the 258 head is know to produce, and to which mine suffers form (but could be from age and deterioration of engine condition too). I don't think this head will produce any real significant increase in HP for my driving, but it will let the engine preform to its maximum (which is a performance increase). This option is less than a 4.6L build, but more than a stock 258 build.
4. Just rebuild the 258 and continue on. If the performance at my relatively low rpm needs from a 4.6L build are marginal at best, keeping the 258 and going to the next step in gearing is best option.
So for the members that went from a 258 (4.2L) to a 4.6L stroker I ask.
What increase or what benefit did you gain from a 4.6L stroker, at this low RPM, compared to a stock 258?
I see none to little increase, but I could be way off.
Thank you.
It is time to rebuild my 258 and I am contemplating several options. I have some questions and my intent is not to bash anything. I am just looking at numbers, understanding how I drive my Jeep and being realistic. The options I can do are: 258 stock build, bolt on a 4.0L head to the 258, build a full 4.6L stroker, of swap in a V8.
My goal is not to make massive HP, but would like a little bump for highway power for mountain passes over the Sierra Nevada would be nice if I could. When I drive I tend to keep her at or under 2500 rpm, and drive 60mph max (I am realistic with a CJ7). I have installed the Howell TBI on her and that works wonderfully and would like to keep that. With the NP435 I installed, she just pulls up mountain hills at slow spends wonderfully. But at 60 mph through the Sierra Nevada freeways/highways. well....here I am looking for solutions.
So I can do:
1. A V8 swap. But this options just seems to costly and more work than I really want to do, but it is not off the table yet. It will yield the biggest difference, but at a cost that is not attractive.
2. A 4.6L stroker. I know they make impressive HP, but at rpms I never achieve. This has me thinking that it may be pointless to build for what I am looking for. I rarely see HP/Torque number below 3000rpm. I did see one 4.6L stroker build HP/Torque printout that was at 2500-5000rpm. At 2500 rpm the HP was better than my 258, but it was way less than I thought it should be considering the extra cost to get a new complete engine. This is not a bash, please do not mistake. It just seems more costly for little, if any, gains at 2500rpm and below. Cheaper than a V8 swap, more than a 258 rebuild, unsure if the gains I could use.
3. Add the 4.0L head to my 258. I know the head has is more efficient flowing and has a better combustion chamber design. The 4.0L head design chamber will deter spark knock that the 258 head is know to produce, and to which mine suffers form (but could be from age and deterioration of engine condition too). I don't think this head will produce any real significant increase in HP for my driving, but it will let the engine preform to its maximum (which is a performance increase). This option is less than a 4.6L build, but more than a stock 258 build.
4. Just rebuild the 258 and continue on. If the performance at my relatively low rpm needs from a 4.6L build are marginal at best, keeping the 258 and going to the next step in gearing is best option.
So for the members that went from a 258 (4.2L) to a 4.6L stroker I ask.
What increase or what benefit did you gain from a 4.6L stroker, at this low RPM, compared to a stock 258?
I see none to little increase, but I could be way off.
Thank you.
