I've got a freshly built 440 that I haven't put a lot of miles onto. wife, kids, business etc. the engine is going into my challenger. it came out of my 74 road runner. both cars are 4spd cars.

when I built the engine it was supposed to 10.5:1 compression, it does have edelbrock heads, m1 single plane and an 850 demon carb. I'm running a the mopar 296 mechanical cam and I'm running 1.6 ratio rockers. also I have 2" tti full length headers on the car. car will be switched over to efi sometime this summer.

I always thought that this car was soft on the low end in the road runner. I think I need to change the spring on the heads to better match the cam. I was debating about the putting the .528 mechanical cam since I have the engine out of the car.

I'd like this car to be in the low 12s upper 11s in street trim. based on the other post on the 340 challenger, getting a 440 challenger there should be easier.

thoughts on the cam swap? anything else I should change while I have the engine out? I'm debating about pulling a head and double checking the compression, since I think its lower than 10.5 I remember the cranking pressure being lower than I expected but don't remember what the numbers are.

Well, you DO have big (2") headers and a single-plane intake... neither are helpful for low-end torque.

The "296" is the .557" (with 1.5 rockers) purple shaft, right? What rear gear are you running? How much does the car weigh?

yes that's the right cam. I've got 3.91 gears in the challenger but ideally would like to run 3.55 gears. guessing the car is about 3750, haven't weight it yet, but it has a fiberglass ta hood. other than that its full steel, full interior,


yeah I guess that's the problem. the combo seems mismatched to me.

You need a roller cam. You will love it. I'm an EFI guy, but would do the roller before the EFI.

Did you degree the cam in or align the dots? If align the dots then you should take the time now to see exactly where the cam ended up being installed on the intake lobe centers. I've seen lazy dogs that had the cams installed retarded by aligning the dots become real tigers by degreeing the cams I helped a customer check his "284" purple shaft that another shop had installed in his old motor, it was 7 degrees retarded, he thought that the motor ran okay, not like the powerhouse I assembled for him with a smaller cam degreed in properly Can you check the valve spring pressures? IF so look for 125 to 160 lbs on the seats and 325 to 370 lbs open, if there 70 to 90 lbs on the seats and under 300 lbs opened see if you can shim and get close to what I recommended If not able to shim them buy new ones and set them up that way IHTHs

What rockers are you running in a 1.6 ratio?
You are going to have to make a lot more bottom end power if you change to 3.55's.
A change to an RPM manifold and the smallest Comp XEHL hydraulic grind (231/237 @.050), should put you right there with the 3.91's. Or, in a mechanical, the Comp XE274 would be a good choice, or possibly the XE282.

I'm running crane 1.6 rockers. I really feel the engine is over cammed. don't plan on racing this much and would love to have a nice flat torque curve to work with on the street.

It's not over cammed. You don't have enough gear. If you think 3.91's are not doable for you, you need to go WAY down on cam and cut the carb size down (leave the M1 on there and don't worry about the header...they OK too).

I use 4.56's every day on the street, with some freeway time. So to me, a 3.9X gear is not much and you want to drop to a 3.5X gear. Tha's damn near stock cam spec territory.

If it's not you DD, put some gear in it and let it be. IMO, a smaller cam and carb will NEVER move lard (weight) like gears will.

The .528 Mopar solid is a great street/strip cam in a big block. I ran one in my 470 stroker with a Performer RPM and HP manifolds. It made 470 RWHP on the chassis dyno. In a 470 it had just a small amount of chop at idle but would idle down to around 800 rpm.

The MP .557 cam is more of a race cam. It has a lot more overlap and will be harder to drive on the street with tall gears and a single plane intake.

I'd swap to the .528 or something close to it. I have some small flat tappet cams sitting on the shelf if you're interested. A small Racer Brown as well as one from Scott Brown that I never used. Might even have some cams left over from the cam testing I did with my 470.

This is probably due to weight but I have almost to the T, the exact same combination as you only in a 3200lb Duster. When I screwed it together two years ago I installed the cam at 104 per recommendations on this site. The car is an absolute animal! It also only has 3.73 gears in it. So I'd maybe check the cam timing first before tearing it apart.