IMM Engines 408 build

Got the new cam and Melling lifters installed... I am in shock on how quite the engine runs now. I didn't realize how noisy the old lifters were until after comparisons. However instead of pre load of 3/4 turn I went 1 1/4 so this might have something to do with it... I don't know. IMM said they go 3/4 turn but can go up to 2 turns max.
As I was removing the old lifters noticed that I could not press down on the plunger inside of the lifters.... except one... it moved without problems at all.... came from the side that was tapping. Lifter might decided to bleed down much faster than the others but didn't seem right. ??

I don't understand why others have mentioned that changing out lifters is hard on the magnums with the heads installed. I didn't have a bit of trouble... they must be talking about Eddy heads.

New custom XFI cam specs: .230/.236 @.50 .577/.572 108LSA

Old cam:112 LSA: Good drivability. Nitrous/Blower. Idle quality and vacuum not as good as a 114 LSA but better than a 110 LSA.

New cam:108 LSA: Aggressive; typically best hp and torque. Moves torque to lower RPM; increases maximum torque; narrows Power band; idle vacuum is reduced; idle quality suffers. Definitely requires tuning. :p

Went with 108 so the torque will come in at lower RPM for this heavy truck.

Cam has a noticeable idle to it now and the off idle throttle response is lighting quick. However it definitely needs a tune now. With the old cam 112lsa it wasn't that bad but with the new 108lsa the computer is struggling. Got in contact with Ryan at Flyn Ryan Performance and sent him some money... shouldn't be to much longer now. :D

I still have not got to install the Ford Racing injectors Ryan has recommended because I'm afraid it will run to rich until he starts tuning. These injectors are 39lb compared to 27lb... we'll see.