Intake Manifold Question... - Chevelle Tech
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post #1 of 10 (permalink) Old Oct 8th, 19, 7:28 PM Thread Starter
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Brian
 
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Intake Manifold Question...

I may be getting my engine refreshed. My current intake is Professional Products Crosswind. It has been nothing but a leaky thing since shortly after I got this engine (oil leaks). I am considering getting a different intake, but I am noticing that none of the small block intakes have the divider cut down on the standard ones - only the air gap models. Is there a reason for this?? The only one I have seen that has the divider cut down that is not an air gap is a Jegs branded one.

Does the divider cut down not have any effect without the intake being taller?? How much would I be giving up by going to one with a full divider?? My problem with the Edelbrock RPM air gap intake is that the water ports are angled - my current intake has them pointing straight up, which works well with my 1971 small block heater control valve. If I get the Edelbrock version, I will have to source a heater control valve for a 1970 Chevelle small block, I believe (they were inline off to the side close to the fender well).

If anyone has any ideas on this one, your input will be greatly appreciated. Thanks in advance.

P.S. I don't know if another brand of air gap type intake would be okay - the Dart ones don't get good reviews (poor castings). Anyone tried the Trick Flow intake??

https://www.summitracing.com/parts/t...make/chevrolet

Here is the standard one from Jegs:

https://www.jegs.com/i/JEGS/555/5130...791+4294829484

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
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post #2 of 10 (permalink) Old Oct 8th, 19, 8:30 PM
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Re: Intake Manifold Question...

On Motor Trend they tested 4 different dual plane manifolds. Here are the results.
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post #3 of 10 (permalink) Old Oct 8th, 19, 8:51 PM
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Re: Intake Manifold Question...

Where is the intake leaking?
I have Hurricane for 13yrs and sealed/seals fine.
I wouldn't worry about the divider not being milled down.
You could always plop a .5" spacer and call it a day.

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post #4 of 10 (permalink) Old Oct 8th, 19, 9:25 PM Thread Starter
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Re: Intake Manifold Question...

Quote:
Originally Posted by WHT/73 View Post
Where is the intake leaking?
I have Hurricane for 13yrs and sealed/seals fine.
I wouldn't worry about the divider not being milled down.
You could always plop a .5" spacer and call it a day.
It leaks oil everywhere. No matter which gaskets I use - or sealant I use on the bolts - the floor of the intake is always oily. It doesn't happen instantly, but over time it just gets worse. I've been running a 5/16" insulator to give me clearance for the power brake booster fitting on the intake (probably no longer necessary with the Edelbrock, but the Speed Demon fuel bowls are pretty big).

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
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post #5 of 10 (permalink) Old Oct 8th, 19, 9:34 PM
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Re: Intake Manifold Question...

Cutting down the plenum divider can show substantial power gains depending on the combo. The one bad thing is you may have to cross jet the Carburetor.
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post #6 of 10 (permalink) Old Yesterday, 12:31 PM
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Re: Intake Manifold Question...

Substantial power gains, in the UPPER RPM range only, not in the drive able areas of lower engine speeds.
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post #7 of 10 (permalink) Old Yesterday, 1:27 PM
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Re: Intake Manifold Question...

Did that and regretted it....can reduce the signal to the carb. Like dave said where youre driving it is where you want it to act right. You wont feel any power gain upstairs by putting a notch in it. Lot of these vids on yt are sponsored...selling parts. And WOT means nothing when it comes to driving.

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post #8 of 10 (permalink) Old Yesterday, 1:34 PM
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Re: Intake Manifold Question...

You might take your existing intake to a machine shop and have it checked for straightness. The last three intakes I've used (SBC Performer RPM, BBC Performer RPM Airgap and Performer 400 Ford) were all warped where the intake meets the head. The bb pass side was leaking oil into the runners and burning / fouling plugs. The sb was leaking between the runners. The 400 Performer I took right to the machine shop and it was out also....

A little machine clean up might be all yours needs.

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post #9 of 10 (permalink) Old Yesterday, 3:58 PM Thread Starter
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Brian
 
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Re: Intake Manifold Question...

Quote:
Originally Posted by Geo71 View Post
You might take your existing intake to a machine shop and have it checked for straightness. The last three intakes I've used (SBC Performer RPM, BBC Performer RPM Airgap and Performer 400 Ford) were all warped where the intake meets the head. The bb pass side was leaking oil into the runners and burning / fouling plugs. The sb was leaking between the runners. The 400 Performer I took right to the machine shop and it was out also....

A little machine clean up might be all yours needs.
Once I get my engine out and to the shop, I will have him look at that. I don't mind keeping it, as it works with my whole setup. I would just like to not have any leaks.

On the off chance that my intake is no longer usable, has anyone used the Trick Flow air gap intake??

https://www.summitracing.com/parts/t...make/chevrolet

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
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Last edited by WakkoWarner; Yesterday at 4:23 PM.
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post #10 of 10 (permalink) Old Today, 7:06 AM
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Re: Intake Manifold Question...

Get whatever fits best. There isn't enough of a HP difference to ever notice it on the street.

Ray


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