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A87 Mikuni 44 Forged Pistons upgraded Cam L20B Q's.


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#1 1979_datsun_620

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Posted 27 September 2017 - 10:03 PM

IF IF IF I decide to keep my L20B...

remember I have a 5 speed L20B 1979 620 completely stock (hence my username), 

 

 

Would you recommend the following?

 

A87 Swap

add dual side drafts (Mikuni 44)

Replace my pistons (recommendations here!)

Upgrade my Cam (Recommendations here too!)

Header Swap and dual exhaust.

anything else to enhance the performance?

 

What should I anticipate as far as HP?

 

Are there any alternatives?

 

My goal is reliability and performance.

 



#2 xUltra510

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Posted 27 September 2017 - 10:04 PM

Following this thread. Thinking about doing a similar setup


DWFL3Hy.jpg

 

 


#3 1979_datsun_620

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Posted 27 September 2017 - 10:09 PM

Only reason is, my L20B is very strong. And i have a 1979...&&&& CA SMOG RULES SUCK ASS



#4 flatcat19

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Posted 27 September 2017 - 10:20 PM

Buy a KA. Cheaper and more power than a hopped-up $3000 L.

You can't hang if your nuts haven't dropped...it's physics


#5 wayno

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Posted 27 September 2017 - 10:25 PM

He lives in California, he cannot do a KA swap, he likely cannot do anything to his 1979 Datsun 620, at least not anything visible.


 

 


#6 1979_datsun_620

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Posted 27 September 2017 - 10:30 PM

Buy a KA. Cheaper and more power than a hopped-up $3000 L.

 

As if I didn't know this already, But even if I swapped a KA into my 620 there's still complimentary parts that I would need to purchase in order to fully perform the swap.

I was thinking of leaving this one with the original engine and later getting a pre-smog 510 and performing the swap.



#7 1979_datsun_620

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Posted 27 September 2017 - 10:31 PM

I have a buddy of mine who can also build a turbo for me on top of those mods too!  :thumbup:



#8 flatcat19

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Posted 27 September 2017 - 11:21 PM

As if I didn't know this already, But even if I swapped a KA into my 620 there's still complimentary parts that I would need to purchase in order to fully perform the swap.
I was thinking of leaving this one with the original engine and later getting a pre-smog 510 and performing the swap.

Buying and installing a KA would still be cheaper than buying just 50hp from an L.


As for your smog issues...I don't think you'll pass with a set of DCOEs. You'll fail with just a visual. Just saying.

You can't hang if your nuts haven't dropped...it's physics


#9 banzai510(hainz)

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Posted 28 September 2017 - 06:41 AM

fail the visual test

 

whereyou buying these 44s from ?

 

 

just pull the head match port to the Intake 1.5 inch

get a Isky cam say 475 or 480 lift and bolt head back on and run it.(get a spare Head on side and build it) so its closer to a weekend job once the carbs are close to set,meaning linkage, cable so ez bolt on)


Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#10 datzenmike

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Posted 28 September 2017 - 06:57 AM

You can't swap the head and you shouldn't anyway. The A87 is not an advantage.

 

You do not need forged pistons unless turbo or SC ing it. Stock are more than fine enough. If needing a rebuild you could overbore and go larger to L28 flattops. They can't be seen by the emissions Nazis and this will up your compression a bit.

 

You can't go  to anything but a stock carb. What you could do is keep the stock carb and intake and swap it back on for any smog checks.

 

Header is out unless it has provisions for EGR which is needed on the '79 emissions. Header may still be illegal.

 

Cam is hidden but will likely throw your emissions into a FAIL. Again you could swap the stock one in for any tests.


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#11 racerx

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Posted 28 September 2017 - 07:04 AM

As if I didn't know this already, But even if I swapped a KA into my 620 there's still complimentary parts that I would need to purchase in order to fully perform the swap.
I was thinking of leaving this one with the original engine and later getting a pre-smog 510 and performing the swap.

...go with last sentence. In the meantime, do your homework as far as what hardware u need and how to.

#12 Stoffregen Motorsports

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Posted 28 September 2017 - 08:42 AM

Dual exhaust? Noooooo.



#13 datzenmike

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Posted 28 September 2017 - 09:03 AM

You could keep 1&4 and 2&3 separate as long as possible.


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#14 distributorguy

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Posted 28 September 2017 - 10:07 AM

Why is this a topic if you need to pass inspection?  I don't even think you can run a Weber DGV and pass.  Unless you re-license the truck as a '74?

 

 

There is an optimum length for header primary tubes.  If you go too long or too short, performance will fall off.  I didn't realize how critical header design is until I bought the software and learned how to measure an individual pulse volume.  You want a header tube that can hold 4, 8, 16, or 32 pulses.  Collectors go at one of those margins.    Dual exhaust would sound like burrito ass.  



#15 2wheel-lee

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Posted 28 September 2017 - 10:21 AM

As for your smog issues...I don't think you'll pass with a set of DCOEs. You'll fail with just a visual. Just saying.

 

Many years ago, I had dual Mikuni 44 side drafts on my 1984 Toyota truck (22R engine) here in California. I knew it wasn't even remotely smog legal, but I took it to a smog shop as a joke to see what they'd say (too bad there was no youtube at the time). The guy looked at it while doing a visual....his comment was that I needed to somehow incorporate the stock air filter assembly "in there" and it would be fine. He seemed so factual in his explanation, which is what made it even more funny at the time. Forget the headers, no cat (did it even have a cat? Can't recall).

 

By the way, there are some counties in California that don't require smog inspections. ;) You're lucky if you happen to have a vehicle registered in those counties...even if you don't live there. ;)



#16 racerx

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Posted 28 September 2017 - 11:03 AM

Why is this a topic if you need to pass inspection? I don't even think you can run a Weber DGV and pass. Unless you re-license the truck as a '74?


There is an optimum length for header primary tubes. If you go too long or too short, performance will fall off. I didn't realize how critical header design is until I bought the software and learned how to measure an individual pulse volume. You want a header tube that can hold 4, 8, 16, or 32 pulses. Collectors go at one of those margins. Dual exhaust would sound like burrito ass.

...he can be thrilling just to rub our rhubarb. Yeh, you can't even buy a smog legal 32.36 weber and yes there's some counties in Cali. That don't need smog, prolly in the middle of the desert or areas where's there's not that many peeps.

#17 datzenmike

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Posted 28 September 2017 - 11:14 AM

There was a 32/34 Weber that was allowed under certain conditions. Good luck finding one, and the rules may have changed.


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#18 Stoffregen Motorsports

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Posted 28 September 2017 - 12:46 PM

He lives in California, he cannot do a KA swap, he likely cannot do anything to his 1979 Datsun 620, at least not anything visible.

Why do you say he cannot do a KA swap? It may not be easy or cheap, but anyone can swap to any engine as long as it's the same year or newer than the vehicle and retains the OEM emissions equipment from that engine.



#19 racerx

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Posted 28 September 2017 - 01:06 PM

He can do the swap but he will need to do all these steps before its legit. My take and seems the easiest and wises, if in California, buy a truck or car that's 75 or below, now less second guessing, weather or not it will be certified by BAR and smog. Minimize the steps and buy 75 and below.

#20 nl320what

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Posted 28 September 2017 - 01:12 PM

Redline Weber got rid of all the Datsun/Nissan smog legal kits.

 

It will have to stay close to stock, so stick with refreshing it with a new carb, new silicon vacuum lines, tune-up, etc.


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