Intake Options

[cbpercy06]

My '87 had an L83 out of an '82 Corvette swapped in at some point. The X-fire system was replaced with an Edelbrock 4bbl 650. I'd like to replace my intake manifold with something that flows better than the pos that is currently on it (#462624), and doesn't have an EGR valve. The issue I currently have is that the EGR was disconnected, and then the valve was crushed until it fit under the air cleaner (not my doing). I cut the valve off and made a plate to fit the hole, but I can't get the motor to run right unless said plate has a small hole in it. Not sure if this is due to incompetence or if it really does need the extra air, but either way I'd like to get rid of the issue altogether and hopefully make a little more power while I'm at it. Apologies for the novel.

TLDR: looking for a decent street intake for an L83 Corvette engine.

 

[Ricko1966]

My '87 had an L83 out of an '82 Corvette swapped in at some point. The X-fire system was replaced with an Edelbrock 4bbl 650. I'd like to replace my intake manifold with something that flows better than the pos that is currently on it (#462624), and doesn't have an EGR valve. The issue I currently have is that the EGR was disconnected, and then the valve was crushed until it fit under the air cleaner (not my doing). I cut the valve off and made a plate to fit the hole, but I can't get the motor to run right unless said plate has a small hole in it. Not sure if this is due to incompetence or if it really does need the extra air, but either way I'd like to get rid of the issue altogether and hopefully make a little more power while I'm at it. Apologies for the novel.

TLDR: looking for a decent street intake for an L83 Corvette engine.

It should not need a hole. The hole is masking another problem. When you fix the real problem you may not think the system you have is a P.O.S and most likely will pickup some power. What problem do you have when the hole is plugged. It isn't running right now, if you have an intentional vacuum leak. WAG is ignition isn't set up right and your designed in vacuum leak is increasing idle speed. Make sure your vacuum advance can is hooked up to manifold and is a working unit. Timing set at 34 degrees( for now) total advance,engined revved until advance stops,vacuum advance disconnected and plugged. Then reconnect vacuum advance. What manifold do you have,not having luck with the numbers you provided.

 

[cbpercy06]

When the hole is plugged the engine has no low end power at all, regardless of timing or idle fuel screw position. The main reason I'm looking for a different intake is that the one that's on it is extremely restrictive, the heads are hypothetically pretty good but GM choked them with a small intake due to smog regulations. It's not a common or desirable manifold, which is probably why there's not anything about it online.

 

[Ricko1966]

When the hole is plugged the engine has no low end power at all, regardless of timing or idle fuel screw position. The main reason I'm looking for a different intake is that the one that's on it is extremely restrictive, the heads are hypothetically pretty good but GM choked
them with a small intake due to smog regulations. It's not a common or desirable manifold, which is probably why there's not anything about it online.

Something funny is going on here, you are talking about a crossfire engine,which had 2 throttle bodies. Now it has a single 4 barrel,but you are talking about the heads are good but gm choked them with an oddball manifold. GM didn't put a 4bbl manifold on a crossfire engine. How bout a pic of this manifold, and I've never heard of a factory GM 4bbl manifold restrictive for smog purposes,that's B.S. A restricted manifold will not help with smog.Is this the same engine that was a 327 on Sept 12th? I am very interested in what you have,and what's going on here. Pics please
Here's some options for you. These are all dual plane,which is what I'd recommend on a basically stock sbc. I think first we need to find out what you actually have,engine and intake and carbureator wise https://www.hotrod.com/how-to/dual-plane-intake-manifold-comparisons/

 

[bucket]

Did the heads used on the Crossfire engines not have really tiny ports like the crossfire intake? It's been a while and I can't remember.

At any rate, I agree, you shouldn't need the hole. It is a bandaid for something not right.

 

[bucket]

But anyway, as far as your intake options go, there's a very large selection of square bore intakes for a Chevy small block. Even among the dual plane style that is best suited for street, there's oodles of options.

 

[bucket]

I don't know if this link will work how I want, but Summit Racing lists 69 different manifolds that are for a small block Chevy, non-vortec, dual plane and also square bore compatible.

Small Block Chevy 350 Gen I Carbureted Intake Manifolds | Summit Racing

Find CHEVROLET 5.7L/350 Chevy small block Gen I Intake Manifolds, Carbureted Dual plane Intake Style, 4-barrel square bore Carburetor Mounting, Stock configuration Cylinder Head Type and get Free Shipping on Orders Over $109 at Summit Racing!

www.summitracing.com