Swaping Quadrajet with Edelbrock Marine 1409 on New 5.7 Long Block Need Advice

[carrera205]

I'm repowering after a cracked block and dropping my old quadrajet (never ending issues with that carb) in the garbage and replacing it with an Edelbrock 1409 Marine Carb and Edelbrock Intake. I'm wondering if anyone has done this switch and if the throttle brackets bolt up or need adaptors.

 

[Fun Times]

I believe the two links below will help some with this question,

CARBURETOR/THROTTLE LINKAGE(ROCHESTER - 4 BBL) Item #'s 22 and 27...Not 23.

CARBURETOR/THROTTLE LINKAGE(WEBER - 4 BARREL)

PS, When possible, please try to keep an eye on past topic dates you're reading...Anything over 90 days old is considered an archive topic here and it's preferred that they aren't brought back up unless it's your own past topic. Thanks for your understanding in advance on that.

 

[jimmbo]

You are going to need a different intake as a Squarebore carb will not fit on a Spreadbore Manifold, Adapters are next to useless.

 

[Scott Danforth]

get a 1-1/2" thick spreadbore to square bore adapter.

 

[Lou C]

If you are against using an adapter, Holley makes a spread bore version of their 4bbl, the 4175. Volvo and OMC used them on their V8s after Quadrajet production ended. They used the 4160 with an adapter on the V6s because the 4175 was too long to fit the shorter V6 intake manifold (would hit the thermostat housing)….

 

[Rick Stephens]

Using adapters also depends on whether you have the room for the taller carb and flash arrestor. But they do work.

You can swap out manifolds. But if you have a boat that ever goes in salt or brackish and is not closed cooling, don't use an aluminum only replacement intake. Either cast iron or a aluminum intake with brass water passages is required.

 

[Bondo]

and replacing it with an Edelbrock 1409 Marine Carb and Edelbrock Intake. I'm wondering if anyone has done this switch and if the throttle brackets bolt up or need adaptors.

Ayuh,..... Welcome Aboard,...... You'll want the Merc throttle cable bracket used on the Merc/ Weber/ AFB that came after the Quadra-jet,....

That carb is a dual-pattern, so an adapter shouldn't be needed,....

You'll need a new hard fuel line,.... I build my own outa 3/8" automotive brake line,......

 

[Scott06]

When you say new long block I assume you ar upgrading from non vortec to vortec ? If so need a new intake matching vortec heads.

 

[carrera205]

scott66 I'm not moving to the vortec just keeping the same pre-vortec setup so i can reuse a number of the components that are still good. I haven't fit up the Edelbrock 1409 to the original cast iron intake yet but reading through the various debates on adaptors seems like something should do a video. I wonder if anyone has done a comparison with and without the adaptor to see if there really is a power difference.

Rick Stephens My boat is really low slung so i don't trust it in salt water where the wakes may be a bit to high so it's always going to be in fresh water lakes. Looking at the marine intake from edelbrock but man it's a fair amount more than the standard version. Could i go with the non-marine version if i only plan to be in fresh water? It's a raw water cooling system. Would love to convert it to a closed but the cost is too much right now.

I've got a rebuilt 350 from ATK coming next week. Would've loved to go vortec but was concerned id end up way in the hole replacing all the parts.

 

[Rick Stephens]

I have just the plain jane Edelbrock Performa on my freshwater only engine. I bought the power package that I installed in my boat while it was still installed in a (organ donor) newer hull that had rotted out. At the time the engine was totally rebuilt zero hour motor that had been upgraded to Vortec by the previous owner. Doing the Vortec upgrade required a different manifold, hence the all aluminum Performa. It had a square bore to spread bore adapter with a beat up QuadraJet installed. I ended up swapping the Q-Jet out for a 1409 - the Q-Jet and adapter was a teensy bit too tall to fit under my doghouse.

As long as you stay out of brackish and salt waters, you'll be golden.

I spent a lot of time in the various year Mercruiser parts drawings finding a clean setup for the fuel lines, mounting brackets and linkage brackets. The 1409 Edelbrock is the exact same carb as the Weber that came stock in many Mercruisers. So you can find OEM parts and pieces where needed to make a clean and safe system.

Rick

 

[Rick Stephens]

BTW, I can't imagine any possible reason to stay with a pre-Vortec if you are going to change intake anyway. Vortec is the way to go and well worth the effort.

 

[Scott Danforth]

a carb spacer (sometimes adapter) adds plenum volume. it makes a difference in low to mid-range power.

 

[carrera205]

Rick Stephens I would love to switch over to the vortec I guess I just don't know enough about compatibility of all of existing parts i have. Would all my of accessories still bolt up on the vortec? Are the mounting holes in the same places?

 

[Scott Danforth]

yes, with the exception of pre 1985 parts. vortec heads have the same accessory holes as 85 and newer heads.

your intake manifold would need to change, however that has been covered before.

so if your motor is a 1985 or later, all your external stuff will bolt into the same location with vortec heads.

 

[Rick Stephens]

yes, with the exception of pre 1985 parts. vortec heads have the same accessory holes as 85 and newer heads.

your intake manifold would need to change, however that has been covered before.

so if your motor is a 1985 or later, all your external stuff will bolt into the same location with vortec heads.

Everything will fit when you are getting a long block cept the intake. Vortec motors add enough flow and efficiency to make anyone's day.

 

[carrera205]

Awesome now I just have to see if I can stop the shipment of the motor I already ordered!

 

[carrera205]

Rick Stephens so i've got the newer vortec on order and it seems like the new block uses an electric fuel pump instead of the mechanical for the earlier model SBC. Any recommendations on which marine fuel pump to use for a carbureted setup?

 

[Rick Stephens]

I used the Airtex, which is one of the OEM pumps. Nice part is, you can get the fittings and stainless hard line between the pump and the carb from Mercruiser sources if needed. You will also need to wire in an oil pressure switch to power it - no oil pressure, no pump power except when cranking the starter.

 

[jimmbo]

get a 1-1/2" thick spreadbore to square bore adapter.

This about the only adapter I would consider using, flipped over of course

l

 

[carrera205]

Rick Stephens I was looking at the Holly Marine Fuel pump for carb engines but they're too pricy especially because I just remembered i have two fuel tanks in my boat which means i need two fuel pumps. There's a diverter switch near the ignition switch that controls a diverter valve so i need to figure how to fire the right fuel pump when it's switched to that each tank.