Help picking 525SC rebuild cam
 

I'm at the point I need to finalize my cam selection so I can get my short block together.

So here's where I'm at, + .030 on the cylinders so 461 C.I., went with 6.385" rods and JE 257969 flat top Pistons with -3cc relief, I'm estimating 8.0:1 to 8.25:1 compression depending on how far in the hole the piston ends up being in the hole. 5-6lbs boost from Weian 177 with planned upgrade tp 6V-71 down the road. I went with EQ320 heads, 2.25/1.88, no porting, just cleaning up the runners and shaping the Chambers, 11/32 valves. Hardin/merc/gil replacement manifolds with low rise Gil E-tops https://cimg9.ibsrv.net/gimg/www.off...422723e721.jpg
And I'm leaning towards Johnson 2112bbr lifters vs the morel 4603's and all of this on a 1994 27ft warlock world class, so around 3,500 to 4,000 lb boat with a bravo 1 behind it.

My goal is to run the motor 4,000 to 4,200 most of the time crusing/skiing, run it hard for an hour at 5,000 if I'm making time, and max out around 5,600 to 5,800 RPM. It's a river and lake boat so I won't be running it WFO very often.

I'm looking at 4 cams, 3 Lunati's and a comp, all with billet cores (Lunati is +$200 for the custom cut due to the billet core). I don't know enough to be dangerous so I could use some advice because I only want to do this once.
1) Lunati# 20110669 -ADV 293/303 [email protected] -234/244 lift 629/612. 114LSA 2* advance built in

2) Lunati# 20110670 -ADV 297/307 [email protected] -238/248 lift 640/629. 114LSA 2* advance built in

3) Lunati# 20110671 -ADV 301/311 [email protected] -242/252 lift 640/629. 114LSA 2* advance built in

4) Comp Cams# 01-446-11 -ADV 289/297 [email protected] -235/243 lift 610/627 114LSA ?* advance built in

What do you think I should go with and why?

Do I need the billet core upgrade on the Lunati's?

I like the #1 Lunati cam. Others are too big IMO for your wants/cubes/exhaust. Billet core is worth it vs cast. I assume the Comp is a cast core?

I'd use a 525EFI cam. Its a Crane 168741 with a 114 lob sep instead of the standard 112. If you had the higher risers, I'd say use the regular 168741.

Griff is the resident 525sc master....but my thoughts... with a good cam and heads, it flows better, so you may have to spin the blower a little harder to make your boost goals, And shooting for 5800 rpm is really going to have spinning. Im not sure you want to spin it that fast.

It's got the teague over drive kit, smaller pulley and super chiller, but your right, I'll be hitting 13k on the blower at 5,327 RPM so I'll just have to stay below 5,300 until I get the 6v-71 set up on there, but one step at a time. I still want to build for 5,600-5,800 max.

Griff, why the EFI cam over the 1st Lunati?

MT to the courtesy phone please, I'd appreciate your thoughts on this too :readinghelp:

Thanks

Probably not a lot of difference. BBC's heads are known to have less flow on the exhaust side, so I'd rather see the increased lift there than on the intake side.

The difference between the first lunati, the comp grind, the 741, and 525efi cam, will be negligible.

I would go with the billet core.

the cams in my engines are 236/245 , .629/.632 lift, 114 LSA. 468 cubes. Theyve been in there since day 1. What has changed, is cylinder heads, superchargers, intercoolers, ignitions, and compression ratio.

from the original setup, they were 9:1 with dart alum heads, 177 blowers with single carb and 5psi. Now they are 8:1 , EQ iron heads, 420 blowers with chillers, twin 850 carbs, 8.5psi, cams retarded 4* (114Icl). Same hull, same drive height, same props. Boat is a solid 20mph faster.

^^^^^^ That is impressive!

Thanks Griff & MT.

What about the melonized or "everwear gear", worth the upgrade? I'm running the original Merc ingition.

Thanks

went from barely being able to turn 28s to 5000rpm, to turning them 6200rpm.

cam choice is important, but its not the end all make or break like some would like you to believe. At least not with roots blown bbc. The power is in the heads , and blower setup. Unless of course the cam is way out in left field