L20 B Intake Manifold

[cobbs710]

Is there a way to separate the intake and exhaust manifolds for a 1976 datsun 710 with an L20B engine? I would like to install aftermarket headers and keep the stock intake. Would a steel plate work to isolate the intake? Could I please get some pointers on this. Aloha.

[datzenmike]

Yes they unbolt. There is a separate plate sandwiched between the intake and the exhaust with two gaskets. You could probably just bolt it back onto the bottom of the intake with shorter bolts. Ive taken one apart and the bolts snapped off in the intake, you don't want that and there is the risk of a vacuum leak.

 

Are you sure you want to bother with a header? On a stock engine they really do very little. For this they are louder, run hotter temps under hood, don't fit that well, come loose /need tightening, are expensive and they get rusty and rust out eventually.

[banzai510(hainz)]

Is this the type that is sandwiched together???? I hate them

 

I would find a 510 intake manifold  or another L20 separate type intake and find a 510 exhaust manifold  if not then get the Top end performance short manifold that is ceramic coated. But quaility is at issue with these soemtimes but its the short type which is dont hang low.

 

If nothing wrong with your car now just find these parts on your spare time than pulling shit apart now then waiting for them

 

 

you most likely can use the intake . it was just a heat riser to get the manifold warm in colf climates but since your in hawaii eating Opihi who cares

[datzenmike]

A '78-'80 L20B intake from car or truck can be used to get rid of your co-joined one. They don't bolt to the exhaust manifold. Then you could use an earlier L16/18 cast iron header exhaust manifold.

 

 

Millions made, perfect fit every time, cheap (free to $25) don't need ANY maintenance and NEVER rust out, quiet, cooler running. They are heavier than a header but no heavier than what you have now.

[Stoffregen Motorsports]

The problem with running an early stock exhaust manifold is finding one. It's much easier to find a cheap header. That's why so many people head down that road.

 

If I had to run a cheap header, I would focus my efforts on the gasket and fasteners. Upgrade the lower 4 bolts to studs, make sure the header is the same thickness as the intake, or make nice step washer to fit, and get the best gasket you can find. The OEM type with metal rings is the best. Try asking for a gasket for a '74 610. I've always had good luck there. Also weld a v-band flange to the header outlet to eliminate any leaks there.

 

If it's assembled properly, with longevity in mind, the only other thing to worry about is the metal itself. You can have it high temp powder coated for probably a hundred bucks, and that would make it last longer than if you left it alone. Typically, depending on the area of the world where you reside, cheap steel headers last about 5-7 years. And typically are a pain in the ass to own, because of the things I listed above.

[datzenmike]

This spring I converted my '76 L20B with the co-joined intake/exhaust manifolds to a '79 620 intake and an L16 exhaust. By drilling two 3/8 holes in the head I was able to run the water warmed/cooled intake. It's all in my 710 goon build thread.

 

Made my own twin down pipe and fixed two exhaust studs that were broken.