Dr. Scagpoople Posted November 21, 2011 Report Share Posted November 21, 2011 So I have a 1977 620 L20b with a crap-pot of emission stuff in the exhaust and intake manifold. I know I can plug all the holes, but what other intakes can I swap to so that I can have a cleaner look and not deal with the intake stove? I would like to ditch the manifold with the egr valve stuff. Currently I have deleted as much as I can. I switched to a weber but I want a smoother looking intake. I will build a header so I don't need to worry about any egr stuff from that. Quote Link to comment
Skib Posted November 21, 2011 Report Share Posted November 21, 2011 get an L16 intake, L16 exhaust mani and the matching dowpipe for it. youl have to cut off the L20b dowpipe and weld on the L16 one. but you be rid of all the bullshit. Quote Link to comment
Dr. Scagpoople Posted November 21, 2011 Author Report Share Posted November 21, 2011 Will the intake ports of the L16 need to be machined to a larger diameter to fit the L20B head? Quote Link to comment
datzenmike Posted November 21, 2011 Report Share Posted November 21, 2011 First you can't change your intake unless you also change the exhaust manifold. That said you can fit an L16/18 exhaust manifold on (as well as the non smog intake) but it has a dual outlet unlike the single one on your L20B. You would have to get a muffler shop make up a dual down pipe into one. Will the intake ports of the L16 need to be machined to a larger diameter to fit the L20B head? Well you can match them to the gasket but it doesn't do that much as the size increase is only as far as you can reach in with a dremel. Best intake for larger L20B size runners is the '78-'79 cars and trucks and the '80 720 truck. These are separate from the exhaust and larger diameter. It does have the bolt on EGR manifold. Quote Link to comment
Dr. Scagpoople Posted November 21, 2011 Author Report Share Posted November 21, 2011 So I can bolt any 1972-1974 L16 or L18 engine intake manifold to the 1977 L20B block? Quote Link to comment
Dr. Scagpoople Posted November 21, 2011 Author Report Share Posted November 21, 2011 First you can't change your intake unless you also change the exhaust manifold. That said you can fit an L16/18 exhaust manifold on (as well as the non smog intake) but it has a dual outlet unlike the single one on your L20B. You would have to get a muffler shop make up a dual down pipe into one. I will be building my own header, so that shouldn't be problem. Quote Link to comment
Z-train Posted November 21, 2011 Report Share Posted November 21, 2011 I will be building my own header, so that shouldn't be problem. Any header on a 620 will COST you HP. Quote Link to comment
Dr. Scagpoople Posted November 21, 2011 Author Report Share Posted November 21, 2011 Any header on a 620 will COST you HP. If I was worried about horse power I would be doing a big block swap. This is a 4cylinder truck. Low and slow is my motto. 1 Quote Link to comment
metalmonkey47 Posted November 21, 2011 Report Share Posted November 21, 2011 Any header on a 620 will COST you HP. Without supporting mods Fixed Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.