The addition of the Eagle rotating assembly will just ensure that you can spin the thing without concern of components finding their way out of the oil pan! The Moroso kick-out pan will aid in oil control and help engine power above 6,000 rpm. The World Sportsman II heads will work well with this combination. The extra compression will be a welcomed addition to the combination. The larger port size over the standard Vortec's will hurt slow-speed torque below torque peak, but should give you a few more ponies upstairs. Between the oil system upgrades and the cylinder heads, we would expect to see 15 to 20 more horsepower than the 450 it produced with the Vortecs. You should still see 500 lb-ft of torque at peak. Remember, the Comp Cams XE282 camshaft is a rather large street camshaft and will require lower rearend gears, and at least a 3,200-stall converter to get the engine into its powerband on the street. Enjoy the power of your 383!
Impala Needs A ShaftQI have a '96 Impala SS, and the other night at a club meeting we were talking about the best camshaft to use in a heavy car like an Impala. One of the guys was talking about a GM Marine cam buildup that you guys had done in the past. I was wondering if I could get the part numbers for the cam, lifters, and 1.6:1 roller rockers. I have a cold-air kit and an after-cat exhaust system by Spintech. Would the GMPP 845 cam work better than the Marine cam? I am also thinking about having a pair of the steel LT1 heads ported and polished and installing headers in the future. Thanks!Paul R. Dumdie Jr.Via e-mail
A The Marine camshaft is very fitting for a boat of a performance car. Oh, did I just say that? The Impala isn't the lightweight hot rod that some of us think it is by its outstanding performance. Yes, the Marine camshaft is rather short, but it builds great slow and midrange torque. This is just what you need to get and keep your Impala moving. Let's take a look.
The 845 cam you asked about is a GM Performance Parts offering that specs out at 214/224 degrees duration at 0.050 inch tappet lift, 0.488/ 0.509 inch max lift, and is ground on 112 centers. With the LT1's short-runner inlet manifold, it is tuned to make peak power. If you add this camshaft with that manifold, you'll see a good bump in power above 5,000 rpm. How often are you above 5,000 rpm? Maybe about 5 percent of the time. The Marine camshaft specs out at 196/206 degrees duration at 0.050 inch tappet lift, 0.431/0.451 inch max lift, and ground on 109 centers. The tight separation angle gives this cam outstanding midrange torque. Adding the 1.6:1 roller rockers gives you a 2- to 3-degree increase in duration and bumps your max lift to 0.460/0.481 inch max lift. This is right where the iron LT1 heads run out of airflow and start to saturate the port. In other words, these parts are very happy working together. You can re-use your factory roller tappets on the Marine cam. The cam is sold under PN 14097395, and the self-aligning 1.6:1 roller rockers are sold under PN 12367346. These components can be picked up at any GM Performance Parts dealer.
Your future plans of ported iron LT1s and headers will work perfectly with the above components. The ported heads won't hurt the slow-speed torque and will give you a good 20hp boost upstairs. The headers will give you more slow-speed torque and will add to that 20 hp from above.
Oils Well That Ends WellQI just read your column in the Aug. '06 issue, as I normally do multiple times, as I find your technical advice to be a great wealth of information. I have a question as to the use of diesel-spec oils in gas engines, specifically Chevron Delo 400. I received the tech bulletin from Comp Cams in regard to the lack of additives in the current motor oil being hard on flat-tappet camshafts, but I was wondering why you stated not to use Delo 400 full-time. I have used that specific oil in my pickups (SBC and BBC) and my semis for years. Once again, I truly look forward to reading your column and much thanks for the technical advice through the years.Albert VaudrinVia e-mail