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1971 Datsun 521


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Maybe the cause. Take a look at the impression the head made in the old gasket. Can't be more that a few mm. I used 1/2" copper pipe and slip with hacksaw. I think 1/2" long.


33 minutes ago, mainer311 said:

There is never a time that I won’t replace the stock head bolts with ARP studs if I’m in there mucking around already. You get way more clamping force on the head gasket, and a significantly less chance of stripping the block.


True, but 60 ft lbs is 60 ft. lbs and how many times is this head going to be removed in it's life time? 2 or 3? so the threads in the block are safe enough. It's definite more assurance than insurance. 



9 minutes ago, Zonargx said:

Also is that a good prices for that single side daft kit?

With manifold I think so. Don't expect too much improvement over a downdraft. Worth it for the sound.

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That's the block vent and it is usually connected to the PCV valve on the intake. I doubt that intake has a threaded hole for that but it is very important for drawing out combustion gasses and moisture keeping your oil cleaner longer and extending oil changes out to 5K miles. 1950s engines didn't have a PCV and they had oil changes every 1-2K miles. Myself, I would drill a hole and thread it, take the PCV off the old manifold and put on the new, and connect it to the block vent. You can run without it. Below... there is a threaded hole on the right side top for a vacuum source for the brake booster (that you don't have) that could maybe fit a PCV valve into. It should be in the middle so all cylinders get some of the blow by but....




The old intake had a hose coming out at the front base of the down draft. Just seal it off, you can't use it on the side draft.


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3 minutes ago, Zonargx said:

You guys recommend just running one of those other Webber don’t know what they are just know you guys mention numbers like 32/32 and will that require a new manifold?

A Weber 32/36. You use your existing manifold, with an adapter plate.

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10 hours ago, Zonargx said:


what are the differences?

Hey mainer311 it looks like hes on a pierce manifold listening but its saying China made?????


Is pierce manifold selling junk now?

I suspected they were selling Chinese jets on ebay under a different seller ...


Zonargx just make sure what you buy is a genius weber no matter who you get it from.....

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I’m going to be putting my truck together tomorrow. Head is out of the machine shop with fresh seals and everything else needed to put back on the l16. I also found another l20b engine number says u67 with a w58 head on it. It has the distributor and what looks like a 32/36 really dirty and rusty for $150

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That l20 has everything on it. Intake and exhaust manifold and alternator with brackets. I’m planning on getting it and rebuilding it as a project with my oldest daughter age 7 who really seems interested on how I fix my cars haha. Would be nice to have her learn some basic stuff

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On 11/16/2020 at 7:53 AM, datzenmike said:



Looks like small hose from head is connected to the return to the water pump. NEVER do this unless you block the flow. The heater shuts off flow when not using it. What happens is very hot water from the head is passed directly back into the engine without any cooling from the heater core. This hot water is by-passing the radiator and straining the cooling system in the summer.




I had the L20B in my truck do this but it was spitting out steam. Same exact spot.





Yea you mean the hose that’s on the back right side of the head to the 3 port part by the water pump ? That’s blocked off in the middle

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