Mopar 340 or 426

[MoparDude]

Hey all,

I have a 1973 Cuda which is getting a full suspension upgrade. Corvette C6 front end arms,spindles, Ridetech coilovers. Rear torque arm setup. Corvette C6 brake rotors with Wilwood calipers etc etc etc.
The car has a numbers original 340 which would require a rebuild, bit its certainly in good condition.
I also have a 426 Hemi Aluminum Indy block, stage V aluminum heads, roller hyd cam, roller rockers, stroker crank (472). All the good stuff. Brand new.

Whichever I use it will be running an aftermarket EFI system with multipoint sequential injection and ignition. I already have this sitting on the shelf.
Transmission I have is a T56 M12 close ratio 6 speed. I dont have a bell housing yet for either engine.
Plan is to set the engine further back and recess the firewall for better weight distribution.

The 340 gives me that "original number" feeling, It would run alloy heads so it probably has a weight advantage over the Hemi. Also located weight slightly further back.
The Hemi certainly comes with ample grunt but adds a lot more weight to the front end and moves the weight further forward. Worse fuel economy (but with EFI it may not be too bad ? ).
Both motors would be pretty mild with an emphasis on response and torque not heaps of revs.

Just putting the feelers out for some feedback on which motor I should run. I wont drag the car, its being built for hillclimb and autocross.

[uxojerry]

I would use the hemi. The mystique of a hemi-cuda is worth a few mpg. If you can afford it rebuild the sbm and crate it with all other original parts you remove from the car.

[go-fish]

If you go with the 340, which I would, it shouldn't be because of numbers, you're going with a completely different suspension and brakes. Numbers are out the window. A 416" will do everything the Hemi can as far as creating the torque you need to get it moving. Also, the weight savings is a plus and you can more easily set the engine further back because of the smaller dimensions, specifically the width and height of the heads and valve covers. The distributor is in the rear on the LA block but a notch in the top center of the cowl should get your engine set back several inches.

If you are looking at selling the car someday the Hemi would be a smarter choice but the small block has more benefits, especially with a good set of aluminum heads, roller valvetrain, and a 4" stroke crank.

[MoparDude]

The distributor is in the rear on the LA block but a notch in the top center of the cowl should get your engine set back several inches.



I'll be running coil packs so there wont be a distributor. Makes it even easier....
The small block does make it generally much easier to fit headers, steering and even air conditioning !!!

If the Hemi wasn't just sitting there in the workshop it would be an easy decision.

[68Cuda440]

340 block, stroker crank, 416ci. Edelbrock ported heads and six pack EFI with a stock style six pack air cleaner. That would be my preference. You can even go with a shaker hood conversion with the six pack if you like. Getting the weight advantage of the small block will result in a better autocross car.

http://www.hotrod.com/how-to/engine/mopp-0811-mopar-electronic-fuel-injection-upgrade/

http://www.fbthrottlebodies.com/products.htm

Call Bruce if you are interested in the intake. They can make the "340" intake w/ the stock style six pack or the mod man six pack intake.