Intake swap

[awsumcars]

I couldn't find any old topics for installing a large port intake on the small port heads. I have a large port intake that has the 4- center bolt ear mounts cut cleanly so it fits under the small port valve cover. It appears the issue is the gasket? I'm sure this has been done many times! Mucho gracious!

 

[Don Jacks]

You're going to have to use the small port intake gasket from what I've seen in the pictures that have been posted in the past.

 

[fourzeronine]

I'd think you'd have to use a tall port gasket and plug the bolt hole in the head.

Keep in mind you'll now have a big honkin' step that's not conducive to airflow in the port.

 

[awsumcars]

I'd think you'd have to use a tall port gasket and plug the bolt hole in the head.

Keep in mind you'll now have a big honkin' step that's not conducive to airflow in the port.

I should have mentioned we're working on a '63 SS w a stock 409 / 340 hp intake and 4GC Rochester carb. Living at 8000 ft. elevation and driving down to 5000 ft. elevation is getting to be a real pain keeping it running consistent, and I'm starting to think changing to an EFI will be the only way to solve the problem. Even though the EFI would adapt to the stock cast iron intake, I'm thinking the aluminum intake would serve the EFI better. Any thoughts on that? Using the tall port gasket and plugging the bolt hole makes the most sense, but as mentioned, would the big honkin step be more of an issue than using the cast iron intake? The car is a daily driver and I'm not all that concerned with high performance, just consistent performance. I would think this large port intake on small port heads would have been done quite a bit, but maybe not . Of course the best bet would be to use a small port aluminum intake, but I imagine they are not easy to come by. Anyone have one for sale?

 

[Don Jacks]

If you're looking for an alloy intake,go Edelbrock small port.The "540" factory intake goes for more money than a new ,in the box Edelbrock costs .They sometimes show up used and make more power as well.

 

[fourzeronine]

Switching to EFI will certainly improve your driveability situation up in the mountains. Use the Edelbrock intake as mentioned by Don if you decide to go the multi-port injection route with injectors in each runner.

You may be able to find an aftermarket TBI system (such as a FiTech, FAST EZ-EFI, or Holley Sniper) that fits your iron intake's carburetor pattern. This would eliminate the need to modify an intake for injectors. I've not looked into the patterns used by these systems, so I can't confirm which exactly would be needed.

 

[awsumcars]

Isn't that always the way......Ya save all these parts for years, ya finally get a chance to use something, and we're still going aftermarket????

 

[Don Jacks]

For what he's doing,his existing intake,and a Holley Sniper throttle body efi will be fine.No adapters or welding needed.That iron 340 horse intake is not a bad piece as it is.These little throttle body set ups bolt directly to the afb/holley mounting surface.His 340 horse intake uses the same mounting pattern.

 

[425/409ER]

I remember before I got the large port Eddy intake I stuck the small port on the big head and it fit fine. I think the other way would work also, no different than the Sq. port intake on an oval port heads, they run fine. Go for it, just use the big port gasket.