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post #1 of (permalink) Old 02-15-2001, 11:31 PM
glennCJ7
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4.0 BLOCK and HEAD / 258 CRANK ???

"How about a multiport fuel injected 4.0 block and head and your 258 crank, this will give you approx 280 cu in and you can get it in kit form, I do have agood 4.0 head and block. MIke"

I've just seen this on Parts Mike board sounds really interesting, a good replacement for my 82CJ7 - 258. Does anyone have any more info i.e. how much torque/HP. What pistions, computor, kit, etc.
Also any suggestions for auto trans (4 sp) to match a Dana 300 T/C?

Many thanks
Glenn

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post #2 of (permalink) Old 02-16-2001, 02:26 AM
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Re: 4.0 BLOCK and HEAD / 258 CRANK ???

I'm currently having a motor like that built. It'll work fine. There are a couple of write-ups on it. I am using a 4.0 head, 4.0 block .030 overbored, custom pistons, 4.0 rods (some people use the shorter 4.2 rods), 4.2 crank. The fuel injection system for the 4.0s will work with the computer. Depending on how crazy you get, you may need an adjustable fuel pressure regulator and some ford (higher rated lbs per hour rating) injectors.

Here are a couple of links to check out:
http://www.accuratepower.com/Jeep/Stroker.html
http://www.bc4x4.com/tech/bryce/stroker/stroker.asp
http://www.hescosc.com/ (these guys sell a kit too, just look around their site, they also sell the EFI kit and the adj fuel press. reg.)

I'll definitely be posting some info when I get the motor in (probably be assembled next week, installed the following).




-raymo
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post #3 of (permalink) Old 02-16-2001, 03:04 AM
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Re: 4.0 BLOCK and HEAD / 258 CRANK ???

Okay, I've done a few hours of research on this and it sounds like a pretty straigh foward thing, except for a few things. I've talked to a few people about doing these and have heard a lot of differnet opinions. Someone had told me that by putting 4.2 parts in the 4.0 block, you'll be creating more a revver than a torqer. Also, I talked to a guy at HESCO and they said they custom make their kits. It's not 4.2 and 4.0 parts(well, some things, like the block and head and crap.) The guy at HESCO also said that some of these other kits(accurate power) on the market and the homemade strokers are going to be revvers, not torquers. And that HESCO's are built for torque becuase of the custom components. Now I don't know who to believe. Some of the people I've spoke with could have their heads in their a$$es and the guys at HESCO could just be bsing to sell their product. What truth is there to this? Hope this made sense

"James and the Giant Jeep"
1993 Wrangler 4.0/5spd, Herculined Interior, D44s Soon
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post #4 of (permalink) Old 02-16-2001, 12:00 PM
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Re: 4.0 BLOCK and HEAD / 258 CRANK ???

I have talked to guys at HESCO about the differences. All of the 4.0 strokers are very similar in design. The basic idea is a 4.0 block (the 4.0 engines have a wider bore) with the 4.2 crank (longer stroke).

There are other things that will either increase it's characteristic as a stroker or increase it's top end ability. Here are a couple I know of:

* If you use the 4.2 rods they are shorter and heavier than the 4.0 rods. You can use the 4.2 rods with stock 4.0 pistons. The 4.0 rods are longer and considered better for torque, but require custom pistons (which I think Hesco and accurate power sell). My pistons are being made by a local speed shop for about the same $$ as Hesco's. So, the comment about the homemade kits being revving is slightly true depending on rods.

* The early 4.2s (I think prior to '80) had a heavier crank. This is better for torque. The lighter 4.2 cranks are better to rev.

* The crank grind can be offset to either increase or decrease stroke and compression. Again, we're talking very small differences.

* Cam choice will obviously allow the engine to perform better at lower RPMs with good torque or High RPM HP.

* Intake/Exhaust set-ups. I know Hesco sells a CNC machined throttle body that inreases flow. Also, the exhaust header type can affect torque v. hp. I chose the Cherokee header partly because it should help in torque dept (also, it was only $100 at a junk yard).

The basic stroker is a common platform. It uses the wider 4.0 bore, but increases stroke by about 1/2". That's the most significant increase alone. All the other things will enhance the basic set-up.

-raymo
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post #5 of (permalink) Old 02-16-2001, 12:05 PM
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Re: 4.0 BLOCK and HEAD / 258 CRANK ???

I've done a lot of research on this. Your best source of info is the eGroups Stroker group (now Yahoo groups). They have thousands of posts from guys who have built strokers with 4.0 blocks and 4.2 cranks. Good info.

As far as Hesco saying it will be a revver . . . well the opinion of the group is that Hesco is full of $hit. Do you know ANYBODY who considers the 4.2 to be a revver?


Ron R. - 90 YJ w/ good stuff [img]/wwwthreads_images/icons/cool.gif[/img]
post #6 of (permalink) Old 02-18-2001, 04:15 PM
glennCJ7
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Re: 4.0 BLOCK and HEAD / 258 CRANK ???

Thanks guys - Great Info.

Raymo do you think your 258 4.0 Head/MPI puts out as much torque/hp as a 4.0L or more?

Thanks
Glenn

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