Will 409 dual 4's fit 348 heads (low-perf)??

[John L. Capps Sr.]

A friend is building a "period-correct" type gasser '55 Chev and has a few 348's laying around. I never was a "W" motor guy, so I would apprec info on interchangeabilty.

Thanks... John L. Capps Sr.
(Ron n Jon are my kids)

 

[de31168]

The issue is in the ports. It CAN be done, but when you put the intake on it doesn't run very well. The 409 ports are a larger diameter so you're covering part of the port and restricting the flow. The fuel air mixture will not all make it into the cylinder head. Edelbrock does make a dual quad intake for a small port 348 motor.

http://www.edelbrock.com/automotive_new/mc/manifolds/chevy/multiple_carbs-348-409.shtml

Good luck to your son in the championship race!

 

[John L. Capps Sr.]

The issue is in the ports. It CAN be done, but when you put the intake on it doesn't run very well. The 409 ports are a larger diameter so you're covering part of the port and restricting the flow. The fuel air mixture will not all make it into the cylinder head. Edelbrock does make a dual quad intake for a small port 348 motor.

http://www.edelbrock.com/automotive_new/mc/manifolds/chevy/multiple_carbs-348-409.shtml

Good luck to your son in the championship race!

That was FAST... I worked in Chev Dealerships starting in 1965 (Mechanic) and never got around to the "W"'s cause the BB just came out. I had a few "big-port" manfolds on oval heads & tuned around it. Thanks for the Edelbrock link. (and thank you for wishing the boy well, I apprec it) John C

 

[59 NSS - 409 Charlie]

John Edelbrock makes one for the small port heads like you have. Good luck Charlie

 

[Clyde Waldo]

The issue is in the ports. It CAN be done, but when you put the intake on it doesn't run very well. ..........[/quote]

When you say it doesn't run very well, I suppose it depends on your expectations. I have been running a 409 truck engine with small port heads with big port 2 x 4 intake for more than three years and it has been OK for my use. Sure it may make a little more horsepower at higher rpm with a small port intake that matches the heads, but for just crusin' around you won't notice any difference in performance (my experience).

I am going to replace the truck engine with the Ronnie Russell built 409 stroker. The truck engine gave me quite a few fun miles as well as three trips to Thompson and back home, so I am going to give it a rest.

The T-Bird should be on it's way to Hill's Thunderbird in Ohio (to repair the damage done by the Frito-Lay truck) less the truck engine and the 700R4 transmission. Grandson and the guys at Southside City Speed Shop in St. Louis pulled the engine & transmission and I brought them home yesterday.

The Ronnie built stroker will be the fourth 409 that has been in the T-Bird. 409 #1 was the stock engine from my 62 SS Impala. 409 #2 was an engine bored .030 and with a better cam. 409 #3 was the truck engine. Looking forward to driving with engine #4 with the 700R4 and the 4.30 posi gears.

 

[John L. Capps Sr.]

Sorry to hear about the "Attack-of-theFrito-Lay-Truck"..., sounds like a plott of a good Si-Fi flick. Thanks for the inf.
John C

 

[de31168]

Clyde I was assuming that he'd be racing the car. It certainly can be done as you have had yours together, it just isn't the greatest in efficiency.

 

[larry t]

There's enough meat in the standard heads to "sorta" port match them to the QB intake. Here's a junk head I played with to see if it would work. I did do a set of 333s and put the OEM intake on it. But since Edelbrock is making a 2X4 intake for the standard heads now, I don't think I'd ever do another set. I don't think the results are really worth the effort when you can get an intake that actually fits.

 

[Mexicanic1]

Hey John,
I have a small port Edelbrock dual quad polished intake with about 20 minutes on it. Just ran it to break in the engine, then found a M/T cross ram to play with. Let me know if interested. Never gonna use it again because we installed Edelbrock big port heads to match.

 

[JimKwiatkowski]

Hey John,
I have a small port Edelbrock dual quad polished intake with about 20 minutes on it. Just ran it to break in the engine, then found a M/T cross ram to play with. Let me know if interested. Never gonna use it again because we installed Edelbrock big port heads to match.

Sorry about posting this message on this thread to Mexicanic1, but this site would not allow me to post a message to Mexicanic1 in his profile with a message larger than 420 characters. Here's the message.

Gabe, I have 1 vacuum line with my crossram and that is for my T400 trans, the line runs from the back of the drivers side carb. I run a Mallory mech advance dist, so I have no vacuum line to the dist. When I ran a MSD dist I ran a vacuum line from the front of my Carter carb on the pass side. I run a PCV line from back of the pass side carb to back of the intake.
I run Carter 600 carbs with stock jetting and my plugs are black also, 409 runs good with no backfire.

 

[Mexicanic1]

Thanks for the help Jim. I will try that out