340 intake and carb setup questions.

Hello i have a 72 340 engine that has been expertly rebuilt using high quality parts with a 30 overbore 10.5 to 1 compression forged Diamond pistons, Eagle forged rods fully balanced rotating assembly etc, etc . My engine builder is a Mopar only type of guy he knows his stuff he said my 340 will be making 400 to 450 HP easy. I dont have heads, intake or carb for it yet. What do my fellow Moparts members think would be good choices for the parts i need to buy. What heads would be good ?, what intake manifold and carb or carbs for a daily street driven car ??. Id love to hear what you think.

What does your expert say?

Alum heads , Edelbrock RPM intake Edelbrock 750 cfm carb but there are other choices too.

There are better choices today for a street car than the Carterbrocks. Here are a couple of articles on the Street Demon. I have installed several on different cars and feel that they are the best OOTB carb for mild to moderate cars that are primarily street driven.

https://www.youtube.com/watch?v=DPOuEOkazVc

https://www.hotrod.com/articles/street-demon-750-carb-review/

Get the right Thermoquad set up properly and never look back!

i like the T-quads as well, but they are not for everybody unless you can tune them. not hard to do, but easy to screw up if you don't know what you are doing and rush it.

How would your expert know the compression before you have heads? Are the pistons flat top, domed, above deck?

Maybe you misinterpreted the engine builder. Did he say your motor: Will support 400-450 HP

A 400-450 HP will not have the same idle and street manners as a stone stock ~300 HP motor.

Intake: edelbrock air gap or RPM

Heads: stock ported or edelbrock

Cam: around comp XE 284 spec range. “Rough idle”

Adjustable rockers to support that cam specs

Demon/Quick Fuel/etc 750 vacuum secondary

TTI or Dougs step headers

A stock 1972 6138/6139 TQ would be absolutely fine on that build, any TQ jets and rods will work in them so tuning is a breeze. I have good cores of either I will sell with a build if you decide to go that way.

*Also, if you plan on running pump gas I'd suggest a cylinder head choice that nets you 9.5:1 or lower final compression or you'll more than likely have problems with detonation.

Exactly. Plus no cam info. Don't know the car's purpose/goal, gear, converter..........

Sounds like my '71 340. I used W-2 heads with a Mopar Dual plane. Racer Brown 286 cam, headers, 750 Holley, 3.55 gears, 3k stall, in a '67 B Body. Runs well. If I remember correctly comp ratio is 9.8 Tell your guy when he builds it to try to get that 10.5 it'll run better if you use a RB cam.

If your willing to buy the best grade of pump fuel with a set of aluminum heads and the true mechanical compression ratio is or close to 10.5 to 1 then you should be fine
There is no way it will work with that much compression on todays pump gas with iron heads
I built a 418 C.I. iron block and a set of the Mopar race W2 heads that had 9.25 to 1 compression with those iron heads, it made a little over 514 HP with a Mopar brand single plane oval port W2 intake that matched the head ports exactly, the owner loved that combination
He drove it all over the country including the one lap around America and several times on the Car Craft cruises from L.A. back east to Detroit or Chicago where ever the cruise went to those years. CRS

If your intent is to have a daily street driven car, move into the 21st century and go with aftermarket EFI. The ONLY reasons I'd run a carb any more is for nostalgia or if I had to.

DaveRS23 The Street Demon 750 cfm carb information was very help full thank you. I love the nostalgia look look 6PakBee thanks for your input.

Hi Scott thanks for your input. Id be interested in your 72 TQ 6138 carb my car is a facory 4-spd restored to new. My compression is already 10:5:1 all new cant replace with lower compression pistons so ill have to run what i got. I plan on using 94 thats the highest fuel octane we have here in Canada.What intake and heads do you recommend i use. My builder said a Edelbrock performer RPM and alum heads i was thinking of a LD340 and whatever alum heads that are a good value for the $$$

Id even use a OE cast iron intake and new steel heads if its a good combination.

I cant use W2 heads as i have a special set of early N.O.S 70s " Hustle Stuff Tri-Y headers that do not have oval tubes they have the standard tubes .

Just so all the fellows who replied to my post im not mechenicly inclined on engine setups so im asking to get a better idea what my options are and what will work for a daily fair weather driver thats reliable to run in the hot summer days.

Do you have heads at all.

The compression is figured with a particular head. The combustion area inside the head directly determines the compression ratio.

So ask the engine builder what head “CC” (volume) he figured the 10.5:1 ratio.

Better yet, just ask him the brand and part number of the piston and people here can figure it out.