~~need a 258 build~~

[Alaskakid]

well hey there fellow forum members,I have a 77 J10 truck 258 4 speed-dana 20. and I am in the process of making it a daily driver /tow rig just too haul a small trailer.or load up the bed. it runs really well after I can get it too warm up in this 30 below as of right now weather. but all in all I want a strong running reliable engine not a crazy power house.I looked at swaps already since I have just about every motor you can think of too swap in.but! I was thinking about getting rid of the truck but it has taken me up the snowy moutain and back with my family too many times without a hickup and figured this old Jeep needs too be brought back too strong running power.

so all in all please let me know what you think I should get built-I do live in Alaska so it would be nice too have a little more power too get through some hills.and tow a small amount.and get decent miles.not a big deal though.so 258 masters let me know what you have in mind.and it will have stock height or 2 inch lift and 31s or 33s still up in the air..

I want too do this right and all the best parts.I know there not a high power engine but im sticking with it.

[Stuka]

When it comes time for me to rebuild the 258 in my J10, which is not too far in the future, I am planning on doing the following.

1: Add a mild cam. Good RV style cam that will add good low-mid range power.
2: Maybe a 4.0 head. They flow a lot better and can add a noticeable amount of power.
3: I may pump up the compression a small bit. Stock is 8:1. 9:1 would be a nice bump up, but not crazy enough to require running premium or the like.

I should note that I already have Weber 32/36 carb, which I HIGHLY suggest. Way better power than stock, and I get better fuel economy as I can cruise on the primary, and use the secondary just for accelerating or when I have a load. I also have a TFI ignition, which was great as well. Since you have a '77, it would work out better to put in an HEI ignition. I am pretty happy with my setup. And I live in steep terrain as well. Which is why I put in a set of 4.56 gears. 60-65 is my top speed really without running too many RPM, but it pulls well.

If you wanted, you can also swap in a 4.0 and use a carb on it, or find one with the rounded intake and use the EFI on it.

As for tires, that depends on your gearing. If you have 3.54's, I would stick with 31's. If you have the optional 4.10's, then 33's would be doable. Otherwise you need to regear.

Oh, and welcome to the forum.

[Alaskakid]

thanks for the reply STUKA~yes I like too plan ahead and have all parts ready too go.
I like your idea of going mild cam-HEI-and head swap.and I know the head swap deal has been brought up quite a bit so I wont ask how or what too get.
and as far as HEI;s go what manufacturer were you thinking of going with and what about a Dui from performance distributers?
and do you recommend any choices for a few solid high quality rv cams?I want too keep my lower end torque of course.and still not sure about the head swap but if I did which is very possible I can figure out that route.

ok and for the carb which I want too keep.you have a weber and you say its excellent what is your opinion on it compared too the 2100 right now I have stock bbd but like I said I wan too do it right.and want too hear from fellow FSJers on there experience with a product.

and also is there a manifold change you recommend?since these are prone too cracks as mine has.
everyones input is highly appreciated!

[carnuck]

Find an Eagle or '81 up Jeep with 4.2L to get the later 2 piece intake/exhaust. Both flow waaay better than the '77 and bolt directly on (allow for PS mounting too)

[Stuka]

For HEI's in 258's I have always gone with units from CRT Performance. I have never had a single issue and they have always performed great without any issues.

http://crtperformance.com/html/jeep_hei_s.html

I am not sure on a cam yet, or manufacturer. Still have some researching in that area.

As for carbs, a 2100/2150 can work. The downside to it is that its better suited for higher RPM as its a big carb for a 258, even if it is the small venturi version. It will provide for more top end power though. The advantage of the Weber is that its a progressive carb. So if you are cruising you run off just one venturi, and then when you give it more throttle the secondary opens up. The lets you have low end torque, but also strong mid range power. Not to mention better fuel economy. Tuning them is different than a normal carb, but once you get it dialed in (Which isn't hard) you don't have to really touch it.

Oh, and like carnuck said, the later aluminum intake is *WAY* better than the 70's unit. It even has an atomizer inside.

[carnuck]

For HEI, I bought one for a 292 Chev and swapped the drive gear with one from my points dist (V8 and 6 cyl use the same gears)

[Alaskakid]

thank you(carnuck) and ( Stuka) ok tomorrow I will have an Eagle two piece intake in my hands.have three Eagles sitting down the road two with a 4.2
and ok stuka checked out the HEI from CRT performance they do look quality and good review on them.
and looks like im ordering up a Weber 32/36
(CARNUCK)~ so you said you ordered up a (chevy)292 HEI unit for the 258?im guessing because it was cheaper and works just the same with e gear changed out~?

[Stuka]

thank you(carnuck) and ( Stuka) ok tomorrow I will have an Eagle two piece intake in my hands.have three Eagles sitting down the road two with a 4.2
and ok stuka checked out the HEI from CRT performance they do look quality and good review on them.
and looks like im ordering up a Weber 32/36
(CARNUCK)~ so you said you ordered up a (chevy)292 HEI unit for the 258?im guessing because it was cheaper and works just the same with e gear changed out~?

Regardless of what distributer you go with, you will want to use the gear off your stock distributer. That gear and the gear on the cam have worn together so you dont want to change just one of them.

[carnuck]

It's not a critical on the 6 cyls as it is with the V8s. The Motorcraft dist gear hole has too big of an inside diameter and it will rock around on the HEI shaft and destroy the cam gear on the 6 which is NOT replaceable without changing the cam. I scored one from a 292 in a Chev van in the local junkyard for $35 complete with cap, rotor, coil and wires. One from a 250 is also the same, but the advance curve for the 292 is closer to that of the 258.

[Alaskakid]

got you thanks.but I changing the cam out so is it still necessary too change out the distributer gear?im guessing change out the cam gear and dist gear?onto the new products? sorry for all the questions just what this too go smooth!

[Alaskakid]

also what do you think of the weber 38/38????

[carnuck]

IIRC 32/36 was the AMC one?
http://www.webercarbsdirect.com/category_s/413.htm

[Stuka]

You can get the 32/36 or the 38/38 for a 258. The 38/38 is a higher CFM and is better suited for high RPM applications.

Oh, and I always buy them through www.carbs.net they offer the complete kits.

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