Donzi502

Use the crane 138551 or similar. Thats pretty close to what we run with 875 HP on a 510 inch platform and it works great. A whole bunch more cam will be hard on valve train and not make much more power. You have a chiller so let the blower do the work. I reacon you will go pretty close or more than 875 with what you have. I think you are making a mistake boring it 100. If you damage a cylinder you got no more to go and how much extra power over a 60thou bore will you make. Sounds like that engine has been set up by some pretty good nascar guys so 6000 shouldnt be a problem with that cam.
Thats a cool boat. I looked long and hard at it when it was for sale here. Have you bought it or was it always yours. I would love to know how you get on with it. How fast it was and how fast after the rebuild. Send me a PM if you like.
Good luck. Jason Frost

johnnyoffshore

Hey Jason,

I remember when you were interest in buying my boat. I did have it at Pier 57 and Frankie gave me your email. Frankie did have it posted on here for sale; I emailed you a few times about the boat. I decided to keep it. I did a refi on my house and paid the boat off and got the wife off my back about it lol.
I am in the middle of converting it to a poker run/pleasure boat. Pump gas motor, back seat, stereo etc…
The engine shop sonic checked the block and said it was good for 120 over or more. So we went with a 100 over to a 475, odd number, huh? We have room for a few more rebuilds.
Boat ran around 95mph with the old natural aspirated 850HP CAM2 motor. I am in hopes of being right back there with blower pump gas motor. But from the sound of it, with you using about the same cam as the crane 138551 and your power, I just might get there or a little more...
I told the engine shop to make the engine user friendly, low maintenance, easy on parts. It was the engine shop decision to let the blower do all the work and a friend recommended me to drop the rpm range from 7000 rpms down to a friendlier 5600-5800 rpm. The engine shop agreed. We are just in the middle of researching for the proper cam.

Jason was good to hear from you, I will keep you posted.
Merry Christmas,
Johnny

PatriYacht

You have more cyl head flow than you will ever need for that size engine. Because of that, you can use a short duration cam. That Crane 551 cam seems close, but in my experience it will make peak power at 5600-5800 in a 540 with really good heads. And the blower will push the hp peak higher also.

nocigarette

you mention eagle components in your post in a fashion that makes them look sub par, i have eagle h beam rods in mine is there something i should be concerened with.....I am about to put it back together know so i would like to know if i am duing something wrong..

johnnyoffshore

Hi PatriYacht,

What cam would you recommend? We plan to under drive the blower, which will be easier on it and make less heat. Airflow numbers in and out it very good. Just need to find the right cam to keep the rpm power range down. We are trying to keep the duration at or below 240 degrees and the overlap in the range of 112-115 degrees. What do you think about the 112 lobe centers and 238 int/246 exh? What would you recommend to keep the rpm power range in the neighborhood of 5600-5800 rpms with my setup?

Merry Christmas PatriYacht,
Johnny

PatriYacht

Eagle stuff works fine for what most of us do it yourselfers do. You just have to make sure all of the dimensions are correct. Up to about 1000 hp and 6500rpm it seems to hold togetherjust fine. I think Arcticfriends uses Eagle in his blower motor at 950 hp.

Johnny, I think you're going to need something custom because your combination is unusual. I'm using a hyd roller 236/240@ .050 .630 lift in n/a 540's. My heads flow 380int/290 ex at .600 lift. Hp is 700 at 5900 with dyno headers. With a supercharger you would generally add more exhaust duration so now it looks like the 551 cam would be good. However, I think with you're smaller cubes, lower compression and 2 dominators on a huge blower, it is going to be a pain at idle and it will have soggy midrange. Just about the time the blower starts spinning at an efficient speed,you'll be at your max rpm. If you really want to run this big blower and 2 dominators on this small of an engine, I would use a small solid roller about 238/248 maybe on 114 degree center and about .650 lift and plan on 6500 rpm redline. I bet with this combination the hp would keep climbing until valve float set in. Somwhere around 1000 hp at 7000 rpm or so. Good luck and Merry Christmas. Ian

Dave F

Staying in the 5800 rpm range, I agree that would be a better choice
That cam starts waking up at 3000 and runs to 6500

DAVE

johnnyoffshore

Thank guys for your help.

I think we are getting close. PatriYacht, if you or anyone else can think of a custom grind and specs that would be better or even an off the shelf cam that would be better then the Crane Cams Part # 138551. I know my combo is odd and this is why we are having a time finding the best possible cam for my application.

Take a peak at these cams a few have PM me about:

Lunati Part #: 502A1LUN
ErsonCam Part #: E129870
CompCams Part #: 11-694-8
and those 2 Crane Cams Part #: 138551 & 138781

Thanks again and MERRY CHRISTMAS TO ALL!
Johnny

TylerCrockett

iTrader: (1)

I would have Cam Motion custom grind something around 630-650 lift and 238- 246 Duration on a 114. With that little engine I would have used a 8:71 blower and 2 -750's. That 14:71 is eating Horsepower that you are trying to gain.

johnnyoffshore

Thanks Tyler,
I will pass the info to the maching shop.