Cam Upgrade
 

Hi I was wondering if anyone can give me some suggestions on a cam upgrade. I am refreshing my engines and I would like to upgrade my cams one step up. The ones that are in there now besides being old are
Crane part# CRN-132561 Specs are intake lift .530/551 exh Adv dur intake 298/306 exh Duration @.050 intake 228/ 236 exh LSA 114. These cams are not available. I looked at Compcams and the specs are not even close.. I am concerned about water reversion. I guess LSA @ 112 will keep reversion away...the exhaust pipes are standard length
Thanks in advance
https://cimg2.ibsrv.net/gimg/www.off...4b24fc9906.jpg

Looks like the old 454/420 hp cam. Hyd flat tappet. I’m assuming you have 454. Not gonna be cheap but I’d go with the crane 731 and change over to hyd roller lifters. Due to lack of zinc in oils without additives is harsh on lobes.

Im assuming these are bone stock including the GM heads?

how about start by telling us what the engines are ?

😂. By looking at his other threads it looks like 502 mags bored 509. Makes no sense to me why the crane 561 cams would be in there however who knows the history on them.

Edit: i had posted another thread by op for getrdun, but he skready saw it :)

see:
https://www.offshoreonly.com/forums/...shut-down.html

I had beat you to it. Funny I felt like I was in a race with you to post and your 1k miles away. 😂

It’s mud season here so trying to fo anything is sloooooooowwwww. Lol

I have the same exhaust but with corsa captains call. I run a 169611 with no reversion issues. Very similar cam with a little less lift and only 1 degree less of overlap than the 731. You shouldn't have any reversion issues in my opinion.
https://cimg6.ibsrv.net/gimg/www.off...b81beecd16.png

ok they are 502's bored out to 509..I bought the boat like this. Engines were done in 2003. 781 heads large oval port. dyno sheet.. 490 hp@ 5200 rpm's. As for the flat tappet cam, that's my preference. less to go wrong. and as for the high zinc oil . I run Amsoil 20x 50 Z rod oil High zinc.. Another choice is Valvoline VR1racing oil high zinc if you do not like synthetics. The only issues I had, some of you know is clicking noises after shutdown lol see link above #6... $850 for roller rockers at least that noise is gone! I really think there is an oiling issue on top.. will soon find out.

Looks like a 110 LSA...I was told not to go any lower than 112 with the exhaust I have for reversion issues

There's a heck of a lot more to go wrong with the flat tappet cams. The cams you're looking at are pretty mild so hydraulic rollers lifters should not have any issues living in the environment. Crane's 169621 would work really well, and is easy on the valvetrain. This is the cam that comes in the 500 EFI. This is a step-nosed cam for use in a GEN VI. Use the GEN VI timing set and it will work great. Comp 929 springs will work and not too expensive. You didn't mention the generation of the block but assuming a Mk-IV or GEN-V so link-bar lifters would be needed.

This is definitely the way.

block is a gen 4. I had several friends who had their engines re-done by the same person and the rollers in the lifters were breaking apart...I have idea why....

If your adamant about staying flat tappet look into the 502/465hp carbed cam. Close to 236/246-.559/.578 ? Can’t remember if they were 110 or 112. Seems like merc got them from crane on a 112. I ran them in some 454’s with ported dart oval ports and was pushing 500 hp at 5800. Never had reversion issues whatsoever but was on the sticks all the time. 😂. That was with lightening headers.

I can’t remember the part number off hand. They sure sound nasty in the 454 but probably a little tamer in a 502/509.

yes this looks good thanks

COMP Cams Comp Cams Xtreme Marine Hydraulic Flat Tappet Camshafts

Part Number: 249-K11-240-4

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Attachment 577313$563.99
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Xtreme Marine Hyd. Flat Tappet Cam Complet Kit
Chevy Big Block 396-454ci 1965-96
Lift: .564"/.566"
Duration: 278°/292°
Lobe Separation Angle: 112°
RPM Range: 2000-6200
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Free Shipping - Estimated to ship direct from manufacturer on 04/01/22 , pending manufacturer availability. Learn More

There you go! 234/244 split with your GM heads be good. Never used that cam but would be a good choice IMO.

https://cimg7.ibsrv.net/gimg/www.off...795df3d382.jpg

All you will ever need.

Or this: (yes, these where real…lol)


https://cimg8.ibsrv.net/gimg/www.off...59cb16a968.png
https://cimg9.ibsrv.net/gimg/www.off...93710212b.jpeg

So if a schaller 1/4 race cam has double lobes.... how many lobes does their 3/4 race cam have??

Looks like something I’ve dreamt about doing when I can’t get chit out of my head. 😂

The Schaller !/4 Speed Camshaft
 

I know this is an older thread, but I do a lot of "Search" for Schaller Camshaft information. I thought I would share some information. I sent a schaller cam to 3V performance to have it run on the spintron. This was a cam ground for Mickey Thompsons 1963 Indy Car. Cam timing is IA: 50, IC:90, EO:90, EC: 50 ~260° @.050. These were fairly low lift camshafts. Short story is this works very well and with modern valve springs, no lightweight components it will spin to 8k. You can see some videos and comments on 3V facebook page July 2023. Just FYI since the cam is referenced in this post. Enjoy!

-Randy

my big radial engine cam runs at 1/8 crank speed some are 1/12th i still dont quite understand it yet