EWB

I need help with a cam for my motor I am wanting around 850 hp give or take. spec. on the motor are as follows.

4.250 stroke (Lunati) interally balanced
4.560 bore (Bowtie block) tall deck
6.405 rod length (crower)
-15cc d cup pistons (Wiseco)1.645 comp. hight
335 AFR cnc heads (121cc) chambers
Littelfield 8-71 with Lee intercooler
Two 1050's by Nickerson

The pistons are .012 in the hole so I think the compression should be around 8.6 with a .042 thick head gasket I have been told to run about 7 lb boost and It should live I would like to stay with a Hyd. roller but also get all the power I can with out having to rebuild this thing every weekend also is there a preference in head gasket for a motor like this and last thing what are your thoughts on total seal rings?
Thanks for your input.
Eric

Dennis Moore

There are three things that should be kept in mind when selecting a camshaft for your application. Wide lobe separation angles (114 to 116), relatively low valve lift (high valve lift is not needed for a supercharged engine) and equal amounts of intake and exhaust duration (normally aspirated engines like more exhaust than intake duration, not needed with a supercharger).

Back4More

EWB, I could fax you my cam sheet...

Our setup...
557CI
4.375 stroke
4.500 bore
+.400 rod
350cc heads
10-71 Blower @ 1:1
2-750 Holleys
This setup made 850HP@5400 on the dyno.
Cams are ISKY Hyd. rollers with 248/258 duration.

Zoomnfun

Is it really going to need 2 1050s??

paradigm shift

TTT

I like back4more specs. Wish I knew the lift. I know there are some out they’re running the crane 741 cam with 236 - 242 with 610 and 632 for lift. They fall off above 5500 pretty much. I have not had mine on a dyno but I run a 651 crane 244 - 256 with 632 lift. I have not run it long enough to speak on lifter life. Hoping to get 300hrs or so on them before replacing. Cam specs will depend on what RPM you are looking to run and idle you are after. There is a difference between max power and reliability. High HP and long life well the are not usually used in the same sentence. There are always trade offs.

EWB

The crane 741 is what I had in it to start with I thought maybe I could get a littel more out of it with something else it had 340 merlins on it and I just ordered the AFR's would it be worth changing the cam or would I not gain that much for the effort.
Thanks Eric

blown1500

Hello, EWB,
I have done an BUNCH of dyno work on the camshaft subject. I found out that blowers like A LOT MORE EXHAUST THAN INTAKE!!!!
The 741 Crane is pretty good. It will often outrun the bigger Cranes in a boat. Ron at Iskenderian can make a cam for you that will run. Try for about 20* more on the exhaust-NOT KIDDING. The intake should be 242-248 @ .050" lift.
The best heads I know of are the AFR,s. They have killer exhaust-which a blower needs. Even then, the cam exhaust must be larger than the intake for the best power. The intake needs to be small relative to NA. Also, don't forget, a hydraulic roller does not live well above 5,800rpm. A good valve train will not require a ton of maintenance. If you like, ask specific questions or pm and I'll try to help. The Merlins are excellent for 454-509, but not enough for a hot 502 or bigger.
Happy Hunting!!!

Back4More

Oops, I forgot to pull out the sheet and list the specs.
The lift is right around .600 on the intake and a little higher on the exhaust with a 114 lobe center.
I will post sheet later from home.
Zoomn has a point...those 1050's might be a little much.

blown1500

Hello, again EWB,
I would contace Cometic Gaskets and have them make a head gasket for you that is more like .030" thick or zero deck the block. A quench distance of about .040" will increase sompression but will give better turbulence in the chamber and cancel any bad effects of the compression increase and improve overall performance.
I also question the use of the large carbs. I have said before on OSO, the best performance is with the RIGHT size carb-that usually means just big enough. Top end will be about the same, but economy and driveability will improve.
Back4more, if you would put about 10* more on your exhaust, you will be pleasantly surprised!!!!!!

Back4More

Isky Grind #RR-294/305HYD.
Lobe Center 114 deg.
248/[email protected]
.608/.617 valve lift

Blown1500, Thats good to know there is still something left before having to go with innercoolers.