454 not as smooth as it should be

[Chevy-SS]

I am running a 454 in my '68 Camaro. It has aluminum heads, full roller cam, tuned Hooker headers and Accel DFI fuel injection. I built this engine as a driver, not a full-out racer. The car is basically stock in appearance.

Here's my problem, the engine runs great and makes plenty of power. It just doesn't feel as smooth as it should. I spent extra money on top-quality parts and having the engine internally balanced just so it would be smooth, but it doesn't feel as smooth as it should. A buddy of mine has a '69 SS396 Camaro and his engine is smooth as silk, even with a big cam.

I would really like to eliminate as much vibration as possible. I am currently using polyurethane engine and tranny mounts.

Anyone got any ideas? Could it be air/fuel ratio? That's easy to change with the fuel injection.

Thanks for any tips.

[ctesla]

figure your 'maro out yet?

do you have power brakes?
big cam and pwr brakes means vacuum loss.
could be the idle, but
did that Accel DFI come with an air/fuel meter?
might spend $50-100. on a gauge (if you do not have) and try and get her closer to stoic.
what's your timing like? and what's your elevation?

[Chevy-SS]

Well, I like a choppy idle, so I have actually retarded the timing a little at idle (easy with the DFI) to make it lope a little more.

When I talk about "smoothness" I am talking about percieved vibration during normal operation, mildly accelerating through the gears. It just seems like there is too much vibration.

I realize it's a big engine making about 550 HP, but it has been meticulously balanced (internally) and all my tune-up parts are top-shelf. Once I get the revs past idle, it should smooth out.

I called Accel and they have a "expert" tuner that they recommended. The DFI system is pretty darn complex, so I definitely need an expert.