HP Gain?

[Zeusimo]

Anyone Know How Much Approx. HP I Can Gain From This?

Swapping The Smog L20B Head With A U67 Peanut Head

And Swapping The Single Intake/Exhaust With L16 Ones

 

L20B, EI Dizzy, 2" Exhaust And Weber

[ggzilla]

About 5 hp

[Zeusimo]

Rly!?

[Laecaon]

U67 peanut head? I want to see pics. I thought it was a firm understanding that they came only open.

[Zeusimo]

A87*

My Bad

[ggzilla]

That's if the combo will give a one point compression gain. If the compression stays the same I'd say 3 hp. Closed chamber is more efficient and more powerful but on the matter of small percentages. I estimate the free flowing exhaust will make a difference in the 5000-7000 RPM range.

 

More importantly your fuel economy might increase about 5%. That's enough to track, even if you don't notice the extra power.

[Skib]

its nice not to look at all the smog shit tho lol

[banzai510(hainz)]

Zeusimo

If your rig is running good now dont bother with swapping anything.

 

Only get the stuff ready for a swap when it goes down then upgrade/update

[datzenmike]

Anyone Know How Much Approx. HP I Can Gain From This?

Swapping The Smog L20B Head With A U67 Peanut Head

And Swapping The Single Intake/Exhaust With L16 Ones

 

L20B, EI Dizzy, 2" Exhaust And Weber

 

This for an L16 motor??? Swapping to a closed chamber head will drop the compression to 8.2 or so.

 

If for an L20B an A87 closed chamber gains to 8.9 compression or about half a point. Generally each point increase in compression gains about 4%-6% power. If you were doing a cam and intake multi-carb this would be worth doing, otherwise....

 

The L16 exhaust manifold would be nice on a W58 head. You will need to mod your down pipe from a single pipe into a 2 into 1. Don't go larger than 2" pipe or you'll loose mid range power.

 

Like Hainz said.

[ggzilla]

Generally each compression point is good for 2 to 3% HP, if nothing else changes.

 

If you go from 9:1 open to 9:1 closed expect a slight power increase after re-tuning the engine for different spark timing.

[datsunaholic]

He said L20B.

 

A87 closed vs W58 open.... L16 intake. So, top end drops, max RPM goes down due to losing volume because of smaller valves and smaller intake runners. Higher compression won't solve that, it'll run out of air sooner. It'll gain torque on the low end (better velocity) and lose on the high end, but to see ANY gains you'll have to retune the timing and switch to at least midgrade fuel. 5% would be liberal; but it's 5% in the lower part of the curve, say around 2500-4000 RPM. Above that flattens out sooner and drops off sooner, which means it'd be an overall loss compared to factory peak.

[RedBanner]

I've pulled 3 w58 round port shielded exhaust heads and they where all peanut heads. Are you sure that your current head isn't allready a peanut head?

[datsunaholic]

Only way to know is pull- I've been 25/75 favoring of the open, but that's still a rather high percentage for the "Really Rare" Closed Chamber W58. I have 2 (one is factory new, never had hardware in it). The other came off my truck, to my extreme surprise.

[ddrum]

I have an L20B with W58 peanut head, weber 32/36 on a L16 intake manifold and L16 headers and EI Dizzy and it runs real good. Not sure though how a a87 vs w58 head will compare as far as power goes, but i like my w58.

[Zeusimo]

I Have Never Pulled The Head

So IDK If It Is Peanut Or Not

 

To Me It Sounds Like This Is Not Worth

Swapping Out Every 2 Years For Smog Haha

[banzai510(hainz)]

to me the simplest improvment would be bolting on a 38/38 weber

[Zeusimo]

I Have A Regular 32/36

I've Been Thinking About A 38 For The Truck

And Putting That 32/36 On My Wagon

Wouldn't You Need To Re-Jet The Carb?

To Get It Running Perfect? :)

[datzenmike]

The 38/38 is for a V6 engine. Might work on a larger 4 cylinder. Contact sealick on here. I think he has/had one and may have re-jetted because he has an O2 sensor.

[banzai510(hainz)]

I had a 38/38 on my semi cammed L16.

went pretty good so I think better on a L20

just off idle on a hill clutching it,I would kill it soemtimes

[datsunaholic]

38DGAS works fine on my L20B with a mild skimmed open W58 and an RV cam, this is in a '74 620. Gas mileage is so-so (low 20s), but it pulls REALLY good compared to a 32/36 or a Hitachi on the same engine. Good acceleration at freeway speeds even in 5th gear. Since it's the load hauler and not the commuter it works for its purpose. With a little pedal discipline it doesn't bog at all.

[ssnapz]

i personaly believe over carbing is a myth, i have a 350 cfm holley on a z24 and with good jetting runs better then people say my motors capable of. i still pullpower at 6k on a napz. and as far as smog goes,im a smog tech most smog techs are idiots when it comes to interchage. they wont know the differance between the heads. if you need more help with smog issues pm me and ill give you my #