69 273 Head and Intake

[273-4brl Dart]

69 273. Wanting to do Edelbrock MPI fuel injection. Edelbrock says it will only fit 340/360 heads. Are the intake runners different on the 340/360 than the 273/318? I am contemplating using the 234 head, blocking the water passages and pressing in hardened seats.

 

[toolmanmike]

The intake will bolt up but the 340/360 intake runners are larger. Not a real issue on a mild street engine.

69 273. Wanting to do Edelbrock MPI fuel injection. Edelbrock says it will only fit 340/360 heads. Are the intake runners different on the 340/360 than the 273/318? I am contemplating using the 234 head, blocking the water passages and pressing in hardened seats.

Here's a rough idea.

 

[65 Dartman]

Bringing this thread back alive. I was thinking about using one of the throttle body EFI’s (FiTech/Sniper) on my 66 273 Commando engine. I was discussing the Sniper with @BergmanAutoCraft yesterday and he said I should go to the Edlebrock Pro Flo 4 instead of a TBI setup. The Edlebrock instructions said one must use 340/360 heads as @273-4brl Dart had posted.

69 273. Wanting to do Edelbrock MPI fuel injection. Edelbrock says it will only fit 340/360 heads.

So I started researching the possibility of using 340/360 heads on my 66 Commando 273. That looks to be a no-go due to the bore size of the 273 and the chamber size of the heads.

The drawing @toolmanmike posted leads me to “think” I should be able to use the Pro Flo 4 as is on my stock 66 heads. Or would it be advantageous to open up the intake ports on the stock heads “some”. The wagon (65 Dart) will be strictly street with the goal of easy starts and running like a modern FI vehicle. So the question for all the more knowledgeable members than me (@RustyRatRod, @318willrun @yellowrose @krazykuda) and any others who care to share their knowledge, expertise and knowledge - will I have issues with the mismatch that matters between the Edlebrock Pro Flo manifold and ny stock 273 heads?

 

[toolmanmike]

Bringing this thread back alive. I was thinking about using one of the throttle body EFI’s (FiTech/Sniper) on my 66 273 Commando engine. I was discussing the Sniper with @BergmanAutoCraft yesterday and he said I should go to the Edlebrock Pro Flo 4 instead of a TBI setup. The Edlebrock instructions said one must use 340/360 heads as @273-4brl Dart had posted.



So I started researching the possibility of using 340/360 heads on my 66 Commando 273. That looks to be a no-go due to the bore size of the 273 and the chamber size of the heads.

The drawing @toolmanmike posted leads me to “think” I should be able to use the Pro Flo 4 as is on my stock 66 heads. Or would it be advantageous to open up the intake ports on the stock heads “some”. The wagon (65 Dart) will be strictly street with the goal of easy starts and running like a modern FI vehicle. So the question for all the more knowledgeable members than me (@RustyRatRod, @318willrun @yellowrose @krazykuda) and any others who care to share their knowledge, expertise and knowledge - will I have issues with the mismatch that matters between the Edlebrock Pro Flo manifold and ny stock 273 heads?

I see no reason why it wouldn't work on 273/318 heads as long as they are 66 and newer. There will be a slight mismatch in the port size but unless you are building a race engine, it's not a big issue.

 

[65 Dartman]

I see no reason why it wouldn't work on 273/318 heads as long as they are 66 and newer.

Yes, stock, rebuilt 66 Commando heads

 

[RustyRatRod]

First, "I" would find out the reason Edelbrock wants to use the 340/360 heads. If it's "JUST" port size, I'm like @toolmanmike, I see no reason why it won't work. Chrysler did that mismatch on millions of engines right from the factory. But FIND OUT first. Edelbrock may have another reason...you never know, so confirm that first. If port size their only reasoning, then I think you're good.

 

[318willrun]

I agree with the other two posted above me ^^

 

[MOPAROFFICIAL]

69 273. Wanting to do Edelbrock MPI fuel injection. Edelbrock says it will only fit 340/360 heads. Are the intake runners different on the 340/360 than the 273/318? I am contemplating using the 234 head, blocking the water passages and pressing in hardened seats.

Do it.
They are smaller, but you can get it right about the same at the entrance/window.
You can raise the port window to the 360 gasket. It will taper some because the runner isn't as tall in cast form, so you would risk the chance of grinding through if you tried to go all the way in... but Its doable and I have done it to know.

 

[65 Dartman]

I just got off the phone with Edlebrock Tech and as the Tech learned, there’s no explanation as to why they specify one needs to use 340/360 heads. We think it’s because of the difference of port size. He said he will get a definitive answer and call me back. Yea!

 

[65 Dartman]

Just got a call back and was told it’s due to their manifold height against the heads

 

[65 Dartman]

I called back later as I wasn’t exactly sure what they meant by manifold height and was told when they cast the intake they matched the ports to the head ports is the explanation I got. All I can figure out is on 340/360 heads the ports were raised significantly higher on the head compared to 273/318 heads. Not taking a chance on the Flo 4, I’ll go with the Sniper

 

[BergmanAutoCraft]

I called back later as I wasn’t exactly sure what they meant by manifold height and was told when they cast the intake they matched the ports to the head ports is the explanation I got. All I can figure out is on 340/360 heads the ports were raised significantly higher on the head compared to 273/318 heads. Not taking a chance on the Flo 4, I’ll go with the Sniper

Why not drill the intake you have and switch over all the gear from the manifold they supply? It’s a super victor so it should be saleable.

 

[65 Dartman]

Why not drill the intake you have and switch over all the gear from the manifold they supply? It’s a super victor so it should be saleable.

I suppose I could have done that but it really never crossed my mind. Rather than take a chance on it, I decided just to go with the Sniper