Rookie

iTrader: (4)

In a '86 scarab panther brochure it says Merc 440's. I have these combined with the TRS425.

Does anyone know what the internals on these engines are. cams, crank, pistons, compression ratio.

I know the heads are large rectangle port.

Just curious

38KV

Must be the 440 Cyclone.

I think they are about the same as the 420 except for the camshaft and springs.

CR 8.8:1

Forged crank and pistons

7/16" rods

cam specs:

Duration in 288 adv, out 296 adv.

Valve Lift in .549, out .558

KAAMA

iTrader: (1)

38KV is correct. It also has the Crane Gold roller rocker arms. Ultradyne Cams manufactured the cam for the old Merc 440hp Cyclone engines. When they first came out they had a Quadrajet Carb on it until they went to a Holley (800cfm I think). The duration at .050" is 231*/239* and they originally ground it on 110* lobes.

rmbuilder

My information shows the lift of that cam to be .550"/.575".
Bob

Rookie

iTrader: (4)

Is this also a good platform for a cetrifical supercharger or small blower like the 420?
Is the cam acceptable for forced induction?
The heads should be large enough? Valves?
Would I need a new intake? (Weiand Stealth I have already)

KAAMA

iTrader: (1)

Yes, the Merc 440hp cam will work in a supercharger application, but most of these cams were ground on a 110* lobe seperation which is kinda tight for a blower application. Most blower applications like/utilize a 114* lobe seperation on the cam. Also, my opinion is that the Merc 440hp cam is a little on the large size for a naturally aspirated 454---especially in a blower application. If you are going to add a supercharger I would select a cam more suitable for a supercharger application.

Sit tight and I am sure there are other guys much more qualified than me that can to this cam application input that would be willing to chime in and help you out here.

38KV

Strange, my information came from this book, it might be wrong.

KAAMA

iTrader: (1)

The intake on the cam could have been .549" but they always told me it was .550" lift and .550" is what actually showed up on the cam card as we had ordered several of these camshafts over the years. When they first made that cam the lift was .550" on the intake and .558" on the exhaust----at least that is what they would tell me on the phone back in the early 1980's when I would call and speak to either Harold (owner/cam designer) or Tim. Later on (early 90's) they increased the exhaust lift to .575" or so. The catalog number they show could be a typo/mistake---heck, with the difference between .549" and .550" we are definately splittin' hairs anyway when it comes to performance.

They also used this same cam in Merc's 460hp (482 cubic inch) engine back then as well. For it's size in duration, I believe this particular cam was a little better suited for the larger Merc 460hp 482" engine than the smaller 440hp 454 incher.

KAAMA

iTrader: (1)

Btw, the exhaust lift of .558" would show up on the cam card as well until they switched the lift later on to .575".

rmbuilder

Kaama,
Harold is still using that cam today in the Lunati Catalog
Part # 302A8LUN
"Most popular Street-n-Strip cam, also 454 Jet boats, Prop boats. Runs from 8.8 to 11:1 CR, 850, headers. Power 3000 to 6200."

Adv Dur @.050 In Lift Ex Lift Lobe Lift LSA ICL
288 296 231 239 0.550 0.575 0.323 0.338 110 104
14 BTDC 45 ABDC 54 BBDC 8 ATDC
Using the lobe lift from the UD master cat:
.323" x 1.7=.5491"
.338" x 1.7=.5746"
however:
.338" x 1.65=.5577"
I know of at least 4 other major camshaft dimension errors in the Merc Manual one of which was in a recent thread (complete with scanned pages and all) where they listed the .050" duration with the adv duration figures. 298*/306* @ .050
http://www.offshoreonly.com/forums/s...ad.php?t=86130
Be cautious when using any Merc publication for camshaft information.
Bob