Cam Upgrade ????
10-30-2011, 08:27 PM
#11
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Then I have no idea why you'd go flat tappet... You could get an off the shelf cam, or for a little more money call Bob here: http://www.marinekineticsonline.com/
You need to figure out your combination a little better before you pick a cam anyhow.
You need to figure out your combination a little better before you pick a cam anyhow.
10-30-2011, 08:47 PM
#12
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Let me give a little explanation here, if you haven't ever talked to Bob before -- Bob is the best cam guy you'll find, plus he'll help you figure out a combination to stay in your budget. He'll help you all the way through the process and get you the motor that fits YOUR needs.
This is the FIRST phone call you should make, and once you do you'll understand. I had my heart set on going with a flat tappet cam in my 502 when I did my rebuild (it was a gen V, so it was a larger process to go roller) to save money, for right around $800 extra with some careful shopping, I turned my 420hp OMC 502 into a 540 hp motor that idles at 675rpm in gear...pretty amazing when my goal was 500hp. You already have roller...just make the phone call, you won't regret it.
This is the FIRST phone call you should make, and once you do you'll understand. I had my heart set on going with a flat tappet cam in my 502 when I did my rebuild (it was a gen V, so it was a larger process to go roller) to save money, for right around $800 extra with some careful shopping, I turned my 420hp OMC 502 into a 540 hp motor that idles at 675rpm in gear...pretty amazing when my goal was 500hp. You already have roller...just make the phone call, you won't regret it.
Last edited by brivander; 10-30-2011 at 08:49 PM.
10-31-2011, 10:26 PM
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So i did some research and yes, roller cams are better and it makes sense but what about lift, duration, lobe separation and rpm range ?? There's where Im stuck now..not sure which route to go. My plans are to eventually go with an edelbrock intake, holley 650 carb, msd ignition, and a descent exhaust. Also, right now the machine shop just did a .30 over with flat top pistons. I didnt want to do too much since I want to keep it as reliable as possible
10-31-2011, 10:39 PM
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So i did some research and yes, roller cams are better and it makes sense but what about lift, duration, lobe separation and rpm range ?? There's where Im stuck now..not sure which route to go. My plans are to eventually go with an edelbrock intake, holley 650 carb, msd ignition, and a descent exhaust. Also, right now the machine shop just did a .30 over with flat top pistons. I didnt want to do too much since I want to keep it as reliable as possible
I won't go and post his cam specs for my motor, but I can NOT believe the specs and the way it idles, runs, etc, I would have never believed it if I looked at the cam card. I would have called
In my experience (very limited) cams are an art, off the shelf cams will work fine but it may or may not match your combination of parts. This is my first and only custom cam, I will never again buy something off the shelf.
Bob -- 585.654.8583
10-31-2011, 11:51 PM
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I would also suggest calling Bob for cam advice since i have never seen anyone unhappy with his recommendations. That said I do not think i could ever be happier with a different cam than the one I have.
http://www.cranecams.com/product/car...detail&p=24208
It is an off the shelf Crane cam that was installed in my 355 when it was rebuilt in 1995. Made 424 HP and 445 Tq on an engine dyno through dyno headers with the stock Mercruiser 320 EFI induction, ignition, and ECU. My 20 ft boats runs 72+ with stock Merc exhaust manifolds with thru hull (under the swim step) exhaust. Idles between 500-600 rpms and has zero issues. Only problem I would see is getting those stock Vortec heads to work with the high lift (my 87 motor uses out of the box iron Dart heads).
http://www.cranecams.com/product/car...detail&p=24208
It is an off the shelf Crane cam that was installed in my 355 when it was rebuilt in 1995. Made 424 HP and 445 Tq on an engine dyno through dyno headers with the stock Mercruiser 320 EFI induction, ignition, and ECU. My 20 ft boats runs 72+ with stock Merc exhaust manifolds with thru hull (under the swim step) exhaust. Idles between 500-600 rpms and has zero issues. Only problem I would see is getting those stock Vortec heads to work with the high lift (my 87 motor uses out of the box iron Dart heads).
11-02-2011, 12:13 AM
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Sorry.. I looked up the 880 block and thought it was a non roller block. Being that it is a roller look at the GM "hot cam" and the beehive spring upgrade. There have been a few guys that have had good results with it. For a little more the guy mentioned above can get you a good custom grind that would give you great results.
11-03-2011, 12:46 AM
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hey guys thanks again for all the advise. I did some research as well and i did call the guru also but due to budget i had to go with a custom grind cam from competition cams. I called summit racing and the guys over there were extremely helpful and guided me to onto getting a marine custom grind cam. It had good lift and duration plus the lobe separation that i needed to go perfect with my setup. lets hope that i went the correct route...Next step is the Carb. Any suggestions ??
