Weber 38-38 on a 258 BETTER than 4.0??!!

[captkhaos]

I called Clifford today to order their 4.0 conversion intake to use with my Holley 350 cfm 2brl. A guy named Larry talked me out of the whole 4.0 conversion thing. He said the 258 was better if I used some (or all) of their mods. He suggested I start with the carb. After all this research I scrapped the 4.0 conversion head for the moment and am going with Larry's idea's for now. I quote from their website though I mixed a few things up so (pardon me) it would flow better:

0- deck the block and mill .060 off the head. Use 1.94 Chevy stainless intake and 1.50 stainless exhaust valves.
DO NOT PORT/POLISH, THE RUNNERS, THEY ARE BIG ENOUGH.[

You will gain up to 360 ft lbs of torque if you follow these simple machining instructions with the 264 hyd cam being the most important addition to your Jeep engine.

97-1972 is our double roller timing set. Please include it with your rebuild kit. $129.00 is a great price.

*BEFORE YOU GET INVOLVED WITH THE 4.0 HIGH PORT HEAD CONVERSION, WE CAN HELP YOU GAIN THE SAME AMOUNT OF TORQUE & HORSE POWER WITH YOUR 258 CYLINDER HEAD WITH SOME MODIFICATIONS.

There is an article online that says you can run your stock 258 intake and exhaust system with the 4.0 head.

This is very wrong because the high port head intake runners are 3/4 inch higher than your 258 and the bolt pattern is different as well.

If you use a 4.0 head conversion, use 47-4520wh intake and 57-2015 header. We like to run the WEBER 38-38 DEGES 2 BRL CARB..

This carb will run up to 6,000 rpm's and blow your mind all through the power ranges of our cams.

OK, so I ordered the carb for a start. I already have a mild Crane cam and I'll see how the specs compare to Clifford's 264 cam. I have a header too so I start with comparatively small money ($339.00 at Weber Carbs Direct for the complete kit) spent. If it's as good as Larry says, I'll mill the 258 head .060 and add the Chevy SS valves. Comments anyone?

[amcinstaller]

why would they change the shape of the ports in the head and keep it if it was worse?? if youre running in a straight line, and have to turn left or right, do you cut a sharp turn or gradually make the corner to maintain speed? thats just how i look at it. ive never built a performance engine though

[SIXPAK]

Sorry

[captkhaos]

Hey... I'm just the messenger. I didn't want to believe what I was hearing as I'd already ordered parts for my new 4.0 head AND I was calling them to order the 4.0 conversion intake. I hadn't ordered the head yet (thankfully) but I ordered valves springs, roller rockers, etc. You can read what they say in the "News" section of their website. You can call them too and ask about the recent race in Florida where they won by 5 laps (or something like that) with a modified 258. Clifford's been doing this for a long time AND they sell the 4.0 head, headers, intakes, cams, etc. all for the 4.0 and 4.0 conversion. Call them and tell 'em it B.S.

[SIXPAK]

I've got some pretty good background on this subject. On a 300 ft sand dragstrip, a 4.0 head is worth .3 tenths of a second. Proved it more than once. Sold a guy a setup and told him if it did not gain .3 I would give him his money back, that was 16 yrs ago.
On my jeep I used the same cam (clifford at the time back in 1989) ,Clifford intake that I relocated the dowels for port alignment, and a good 4.0 aftermarket header. Dropped ET from 5.6 to 5.25.
Just my .02

[bbarrett]

I don't want to argue with anyone, But i put the 32-36 Weber on my 258. Then i did the head swap (0630). Then i did the stroker thing (4.7). After the head swap i really didn't notice anything different, Except i could run more timing without detonation. Power was about the same. However the 258 intake WILL fit a 4.0 head. You must cut the bottom out of the dial pin holes and be very careful aligning up the manifold to ports. The reason for this is the 4.0 head has the roof notch for the injectors to spray. But it will fit. If anyone wants pictures i will be glad to take some. On a side note i will say the 32-36 Weber is to small for the 4.7, As i still have about 1 inch of vacuum at wot. I would like to try a 38-38 on my setup, But I'm probably going injected so i can turbo easier.

[farna]

Don't cut the dowel pin holes out into slots on a 258 intake. Just file a notch in the bottom of the "ear" that has the hole in it. Set the intake on top of the dowel pins. The top edge of the intake should be even with the top edge of the head, that will align the ports.

The 4.0L head will flow more CFM at low to mid rpm than the bigger port 258 head. At WOT the flow is closer to the same. You get a better jump off the line with the 4.0L head. The head and exhaust alone won't make engouh difference to notice "at the seat of the pants". Maybe 5-10 hp (average about 7 hp). That's just not enough to notice or justify the cost. But there is a lot more potential flow. Upgrade the intake and carb, the rest of the exhaust system, and the cam and you'll get a better power increase than with the older tech 258 head. It's not a huge difference in power, but the power comes in where it's most needed -- low to mid rpm range (500-2500 rpm). Above that there isn't as big an increase, but the head with supporting mods will still flow better and produce more power over the 258 head with similar mods. If you have a perfectly good 258 head the swap is dubious. If the 258 head needs rebuilding, the swap makes a lot of sense.

[cruiser54]

Captkhaos, whaddya gonna run for ignition?

FWIW, I put a 38/38 on a 258 and it ran great. The other thing that helped immensely was the addition of an HEI distributor.

[gmakra]

I know Larry from my time in So Cal he inherited Clifford by marriage after Jack Clifford died. Larry is a nice guy and means well however after Jack died he never made any improvements other than the 264 cam which was figured out by a cam grinder he uses. Jack Cliffords idea was all out racing (desrt and drag)which isnt compatable with DD

I have gone through several incarnations of Clifford products and while they are very well made I do see some design issues. If you look at the Clifford intake manifold (which by the way is made at the same foundry in LA as Offy) you will see the intake runners are huge. This is great at high RPM but causes bogging and stumbling at very low RPMs till velocity get the fuel charge into the cylinder. Also it is missing machining for the EGR you will see the boss there but its never been machined to see if it will work. This is not a big deal unless you run into SMOG compliance someplace. The other thing is there is no electric heating element in the manifold and that makes starting in cooler to cold weather a real PIA.

The 4.2 head is not as bad as people say but its not a 4.0 head,The 4.0 is just plainly more evolved in air flow and even cooling flow.

I am as of this weekend pulling out the Clifford 264 cam it is in good shape however I just dont like it it seems to come on between 1200-1500 RPM and is pretty good after that in any incarnation carb, Howell TBI and Redline TBI. It faired better with the Redline TBI but is still had that higher RPM thing happening. I dont like it if you want I will give it to you along with the lifters for shipping.

My suggestion to you is get the Weber, upgrade the ignition Team Rush, HEI or MSD or what ever you like.Then if you arent happy research the cams and come up with a grind that will work for you.

The 4.2 will be a lot better but it still wont be a 4.0





The only thing I agree with is the call on the Weber and I think he still sells the real deal not some knock off.

[KnuckleUpPunk]

Before I start, let me say that I am not defending the current Clifford Performance. I was at Clifford when it was in it's prime and it pains me to see the company and it's products have the reputation it currently has.

I know Larry from my time in So Cal he inherited Clifford by marriage after Jack Clifford died. Larry is a nice guy and means well however after Jack died he never made any improvements other than the 264 cam which was figured out by a cam grinder he uses. Jack Cliffords idea was all out racing (desrt and drag)which isnt compatable with DD

As a former employee during the Jack Clifford days, I can tell you that the cam was NOT "figured out" by the cam grinder (Babe Erson back in the day, but I "think" Steve does them now in Corona). In the begining of the TBI days, there were two different versions of the 264H cam offered - a 264H and a 264H EFI. The EFI version was ground on a 114 LSA. This bleeds off less cranking compression and provides a stronger vacuum signal for the MAP or Carb. As time went on, the 264H EFI was really the only version offered (unless the tighter LSA version was special ordered). When Jack passed and Larry "let everyone go", he probaly was having the incorrect profile ground and selling the 264H mistakingly as the 264H EFI version. The real Clifford 264H EFI was a highly tested and sought after camshaft for many, many years. Hopefully it isn't a complete POS now.

I have gone through several incarnations of Clifford products and while they are very well made I do see some design issues. If you look at the Clifford intake manifold (which by the way is made at the same foundry in LA as Offy) you will see the intake runners are huge. This is great at high RPM but causes bogging and stumbling at very low RPMs till velocity get the fuel charge into the cylinder. Also it is missing machining for the EGR you will see the boss there but its never been machined to see if it will work. This is not a big deal unless you run into SMOG compliance someplace. The other thing is there is no electric heating element in the manifold and that makes starting in cooler to cold weather a real PIA.

First - The EGR boss is there, but not machined because not everyone runs an EGR. Jack designed the boss into the manifold and let the consumer decide if they needed it. Back in the day, we'd machine the EGR for special orders.

Second - The Clifford manifold is a water heated design. You don't need an "electric heating element" to heat the manifold. You plumb your cooling system into the manifold and it heats it perfectly to avoid loss of atomization.

The intake manifold for the 4.0L head conversion from Clifford is simply just their 258 intake with dowel attachment points added to match the raised runners on the 4.0L head. The runners are not large enough to cause a loss of atomization or reduce the inlet charge to the point of bogging and/or hesitation that you mention. In fact, if you cut the manifold in half for a cross section view, you'd see the engineering Jack did to help balance the inlet charge to each cylinder. Jack was well aware of the fueling issues with an inline 6 and he used his aerospace engineering background to avoid these exact issues in his designs. It sounds like some of your issues are from not plumbing the heated water into your manifold.

That said, I would also take another look at the cam you received from Clifford when you pull it out. If it were me, I'd put it in a V Block and check the profile completely. Another thing to note is that we used to grind 2° of advance into the 264H EFI cams as well, so take that into consideration when checking the profile. Personally, I wouldn't trust any Clifford camshaft to be correct that was shipped after Jack passed away, but that's just me I guess. It's important to note that you'd have the low speed drivability issues you mentioned if you're running a MAP based EFI and the cam was ground with the tighter LSA. Add to that the lack of heat to the manifold and it's easy to see that your Jeep must have been a PITA to drive.

The 4.2 head is not as bad as people say but its not a 4.0 head,The 4.0 is just plainly more evolved in air flow and even cooling flow.

I agree with you here, if you maintain a stock 258. The second you add an intake, exhaust, cam, etc.. to improve airflow on that 258, you'll benefit greatly from a 4.0L head conversion. The 264H EFI cam profile works excellent with the port flow numbers on the 4.0L head too (flow vs lift). If you can, try to get the "7120" 4.0L head casting. It's by far the best of the 4.0L heads and the only casting I used while at Clifford for the conversions.


RIP Jack, you truly are missed by many.

[nosigma]

KnuckleUpPunk: X2

As a customer of Clifford Research / Engineering from back in the 70's until today the difference is night an day. Build quality, knowledge and customer service are completely different. Well written.

John

[Khawk]

In 1997-98 I worked the 1-800 tech line for Federal Mogul, Trw, Sealed power Bower BCA and National oil Seal. I got to talk with some very interesting people while I was there. I spoke to Richard Petty's team, Bob Glidden's shop, Ross Pistons Crane and lots more. On one call I got to help Don from Valley Head service in California. During the 60's-80's Don was the go to guy for head porting. I had a 95 XJ with a 4.0 at the time and asked about getting my head ported. He said to use the 65-71 head as they have much bigger ports. The new heads have raised intakes, but the exhaust ports were to small to do anything with. There have been rumors of a replacement 4.0 head recently, and if it has enough meat to port out the exhaust that would be the way to go.
When talking to Don, who has been written about untold times in Hot Rod, Car Craft and Hot Rodding, he mentioned that he worked on the AMC V8 cylinder head design. He personally ported a pair of 70 390 heads and got them to flow more than a BBC a Rectangle port head. Now there are all kinds of aluminum aftermarket heads that do better on both sides of that comparison.
Keep in mind, in the late 60's Indy allowed stock block engines of 200 CI and smaller to go head to head with the turbocharged OFFY's that were popular at the time. One team took a 262 Chevys small lock and destroyed it to 200 CI but it's power was too peaks and it fell short. Another team ran an AMC 199 and did very well until the were bumped from the field. This engine made enough power and had they had more time to tune the car it would have ran.

[Cinaed57]

This is reviving an old thread, so I am hoping some with knowledge and experience on these things can contribute and help me out.

I have a tired Jeep 258 with a Motorcraft MC2100 carburetor. I think it has the 1.08 jets, but it was installed in 2005 to replace the anemic Carter BBD, on which I had done the Nutter bypass with some success. Back then, the MC2100 was a HUGE upgrade and improvement.

So, at this point I believe I need and want to do the 258 block equivalent to "stroking" the engine if that term can be applied to this setup.

I really need a replacement transmission, so I believe the thing to do is swap the NP435 I have for something rebuilt, perhaps from Novak-Adapt.

But I need a better running carburetor, and I could do the straight replacement, sure; but I need more power for towing and long hauling.

So I really want the 4.0 aluminum head from Edelbrock, plus the Dual Weber 38/38 DGAS setup from Clifford Performance. Plus headers, and I'm sure those from Clifford will do nicely. I'm not really expecting headers to add much more than a decreased level of noise from the engine compartment as the stock exhaust has too many failure points which cause exhaust leaks. I'm thinking of those ports designed for the old air pump which have brass plugs, et al.

But I like this proposed combination of the Edelbrock head plus the Clifford Dual Weber 38/38 Carburetor to produce a substantial increase in horsepower that I live with, and it will coexist with my other stock components, such as the Borg-Warner/Tremec Non-World Class Jeep T5 transmission.

Any experience or knowledge regarding the 4.0 head, iron or aluminum, and a performance upgrade, such as those offered at Clifford, or other carburetor upgrade and how this affects the Jeep 258 engine would be interesting to read.

Btw, this is in a 1982 Jeep Cherokee Widetrack, 258 engine, T5 transmission, NP208 transfer case which is driver side drop. It has new 33 inch Firestone Destination mud terrain tires. A different axle gearing was installed in 2007, which doubled the gearing from the stock 2.72:1 gear ratio to 3.73:1. Maybe I should have gone to 4.10 or even 4.56. But these are ok for now.

Your thoughts, please.