Edelbrock 4.0L head soon to be available.

[SilverXJ]

According to the part number 5814 for the spring in their catalog it is not a typo. That is around a 400 rate spring. However, going off the book numbers it is a 357 rate spring.

That spring is spec'd for one of their roller cams for a Chevy 4.3L 90* V6

[jsawduste]

According to the part number 5814 for the spring in their catalog it is not a typo. That is around a 400 rate spring. However, going off the book numbers it is a 357 rate spring.

That spring is spec'd for one of their roller cams for a Chevy 4.3L 90* V6

Hell of a spring Chris.

My bogey has been 115 or slightly less on the seat and 245 or so @ .500. To lazy to do the numbers but if it is a 357 or 400 spring rate it is quite stiff.

Bennie's springs come in at 115 at 1.8 ish (he says 1.7 but that brings them up 135 or so IIRC) at 1.8 installed @ .500 it is about 245. Much better IMHO.

Given the physical dimension of the spring itself do you se any other choices in the EB catalog?

Double post above, my bad

[Jim K in PA]

For a milder, low RPM/high torque build, it might be wiser to get the bare head. Depending on the price difference, that might be quite a bit cheaper, too.

[jeepxj3]

What are the stem size? What are the retainers and locks? 7, 8 or 9 degree?

400 lb/in springs are too much spring rate.

A possible better spring would be the Comp Cams 26125.
258 lb/in, 104 lb at 1.71" install height and 221 lb at 1.25" (.460" lift)
I doubt a Comp Cam spring in an Edelbrock head.

If they go with that heavy spring, it would probably flatten the cam lobe within 5000 miles. That would suck.

[jeepxj3]

According to the part number 5814 for the spring in their catalog it is not a typo. That is around a 400 rate spring. However, going off the book numbers it is a 357 rate spring.

That spring is spec'd for one of their roller cams for a Chevy 4.3L 90* V6

Maybe their 5813 spring would be a better choice.
252 lb/in 80 lb at 1.70" 200 at 0.475"
maybe add a spring shim or 2 to get 90 lb at 1.70.

[jeepxj3]

It looks like Edelbrock uses on this head- valves are 11/32" stem and retainers and locks are 7* single groove.

Just for comparison- stock are 8mm stems and retainers and locks are 8* and single groove '87-'97 and 3 groove '98-'05, ?'06.

Edelbrock springs are dirt cheap, less than $35 for 16pcs either 5814 or 5813. I wonder if Jeep retainers will fit these springs?

[Torqsplit]

I'm delighted to see a large-scale mfgr catering to the 4.0L platform. That anyone is paying attention to this 'old mill' in today's market amazes me, so I think its firkin great that there's a new option! I find it especially cool that they went to the bother of getting a smog EO # for this thing so you can hot-rod your Jeep and still pass inspections. I feel its almost completely moot that this head offers any benefit on a 4.0, when hopefully it exists to improve on stroker power potential. Who really builds a 4.0 these days now that strokers are so popular? Im most interested in seeing numbers where someone swaps a healthy 7120 for it, or even better an OBD-2 stroker with some of Flyin Ryan's tuning. An aluminum head 'should' allow for some pretty aggressive timing advance. If Edelbrock can put together a quality cam & valve-train pkg that shows REAL improvement over current setups, I might actually consider laying down this kind of $$ for a build. The +25hp dyno-graph for the 4.0 is nice, but what'll it show on a 4.7 build with a 5,250rpm rev limit???

[6TIME]

The extra volume in the runners should let the strokers breathe much better as well It'll be interesting to see the dyno numbers when these heads get out to the public.

[jsawduste]

I'm delighted to see a large-scale mfgr catering to the 4.0L platform. That anyone is paying attention to this 'old mill' in today's market amazes me, so I think its firkin great that there's a new option! I find it especially cool that they went to the bother of getting a smog EO # for this thing so you can hot-rod your Jeep and still pass inspections. I feel its almost completely moot that this head offers any benefit on a 4.0, when hopefully it exists to improve on stroker power potential. Who really builds a 4.0 these days now that strokers are so popular? Im most interested in seeing numbers where someone swaps a healthy 7120 for it, or even better an OBD-2 stroker with some of Flyin Ryan's tuning. An aluminum head 'should' allow for some pretty aggressive timing advance. If Edelbrock can put together a quality cam & valve-train pkg that shows REAL improvement over current setups, I might actually consider laying down this kind of $$ for a build. The +25hp dyno-graph for the 4.0 is nice, but what'll it show on a 4.7 build with a 5,250rpm rev limit???

We shall see in a couple weeks.

[Cheromaniac]

The extra volume in the runners should let the strokers breathe much better as well It'll be interesting to see the dyno numbers when these heads get out to the public.

The intake manifold will be the limiting factor as far as intake port breathing goes. The late model curved runner manifold has smaller runners aimed at improving midrange torque, so they don't breathe so well above 4500rpm.

[6TIME]

The extra volume in the runners should let the strokers breathe much better as well It'll be interesting to see the dyno numbers when these heads get out to the public.

The intake manifold will be the limiting factor as far as intake port breathing goes. The late model curved runner manifold has smaller runners aimed at improving midrange torque, so they don't breathe so well above 4500rpm.

With all due respect Dino, I'd like to throw a thought out there regarding intake port cross section and flow limiting factors of the manifold... If you look at a Edelbrock Performer Ford 5.8 EFI manifold, the exit cross sectional area of the runners is 1.85" X 1.04" Equating to 1.924 sq. inches. I have seen these 5.8 manifolds in 351w swapped stangs at the track spinning happily past 6000rpm with the right cam/head setup. If the 99+ manifold measures 1.53" x 1.26" equating to 1.9278 sq inches, then I can't see where the huge restriction is at 4500rpm with the 99+ intake runners? The 351w Torker II carb intake has even smaller ports at 1.02" x 1.82" = 1.85sq in. cross and its made to run from 2500-6500. Why exactly do you feel that the 99+ manifold is the primary restriction here?

[Cheromaniac]

It's the length as well as the cross-section of the runners that'll determine the rpm range where the manifold works best.
While you're correct about the exit cross-section of the Edelbrock Performer Ford EFI manifold runners, the runners are tapered (to increase airflow velocity) with a much bigger cross section where they begin at the plenum.
Finally, each cylinder in a 4.6 I6 stroker displaces 764.5cc whereas the figure for a 351W is 720.7cc, so the 4.6 I6 would need larger cross-section runners than the 351W to match its rpm range.

[Jim K in PA]

I have often wondered how much turbulence is caused by the throttle body being so close, and perpendicular to, the floor of the manifold. The later manifold has a much higher total volume than the earlier one, but I still think a TB mounted at an angle toward the ports would reduce this torturous hard turn that the intake air makes, especially at higher RPM (velocity).

The 5.8 manifold mentioned above creates a 180 degree path from the TB to the runner, but the TB is MUCH farther away from this transition point.

I also wonder if Edelbrock has a manifold in the works for the 4.0.

[Jim K in PA]

I also wonder if Edelbrock has a manifold in the works for the 4.0.

Answer to my own question from Troy at Edelbrock:


Hi Jim,
Not at this time. Maybe next year.

Thanks!

Troy Hooker
Sales Manager
Edelbrock, LLC.
2700 California ST.
Torrance, CA 90503
310-781-2222 Ext. 2813

[Cheromaniac]

I have often wondered how much turbulence is caused by the throttle body being so close, and perpendicular to, the floor of the manifold.

That's where the TB spacer may be of benefit by placing the TB 1" further away from the manifold floor.