cdaniel525

iTrader: (1)

Curious on what you guys think I may come up with on a 598 I'm having built... I'm replacing a 632 (10:1 comp) with AFR CNC 335 heads, hydraulic cam: 262/270 --- .720/.720 lift --- 112 LSA, Edelbrock Super Victor intake, and 1050 dominator, but had some oiling issues... And a few builders and enthusiasts said those heads and cam were a bit small for the 632. And I'm going to do the 598 to avoid the 632 oiling issues. With that said I am hoping to get back to the same power / speed I was previously at.

Here's my spec'd build so far:
Dart Big M 10.2 block
598 rotating assy
10:1 comp. ratio
Brodix Xtra-O 351cc Flow #s -
VALVE SIZE 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900
2.350 INTAKE 50° 154 226 300 356 405 433 441 444
1.880 EXHAUST45° 134 177 216 249 277 304 308 313
Brodix oval intake CNC port matched to the heads
Solid lifter, custom grind cam; 272/280 @ .050 --- .756/.756 lift --- 114 LSA
Comp ultra pro magnum XD rockers
Dominator 1050

Short block is already built, cam is in, and heads are on order. Would love to hear everyone's thoughts on what I may make for power and/or any suggestions / comments....
Thanks in advance!

ICDEDPPL

iTrader: (1)

Looks like a great combo to me.
Cam seems big and quite a bit of lift for marine but I`m not cam expert . I thought my .680 lift cam was getting up there .

cdaniel525

iTrader: (1)

Fingers crossed, lol

cdaniel525

iTrader: (1)

Me either.... But had .720/.720 in the old cam and she ran pretty damn strong, and that was with the smaller heads as well. Like you said tho, I'm no expert! lol

sutphen 30

we have a 1075 w/ .714" lift cam,been running about 125hrs.have good PAC springs and check lash twice a season.
and Mark Boos has a few engines out there w/ the same cams,alot of cats and we're a 46 OL

cdaniel525

iTrader: (1)

1075 as in a Merc 1075SCI? Either way, do you think thats too much lift for this motor? Do you know what your duration is for that cam? Mine is going to be 272/280 @.050 and N/A motor. Also hoping I'm not going to have to rev to 6500k rpm to get the #s I'm looking for.

GPM

The solid roller is fine with good lifters and enough spring. I ran a 276/284 .782 lift in a 598 with Brodix heads, peak HP was 6200 without the Procharger, on the dyno. I like a 112 vs 114 for bottom and midrange torque. What are you doing for exhaust ? Best of luck to you with your build !

cdaniel525

iTrader: (1)

Damn sounds somewhat similar of a build 👍. I'm also 114 LSA, but just a bit smaller on cam specs. I'm running CMI Etop headers, tails dry to the tip outside the transom.

And that max 6200 RPM sounds perfect. Do you mind sharing what your HP/TQ was? And some more details, such as which Brodix heads, what intake, compassion ratio, etc etc
thanks

KAAMA

iTrader: (1)

Sounds like a very interesting project---I actually like the idea of your current AFR 335cc cnc ported heads for a 632cid engine for marine use at about 5800rpm and below, but I am curious to know what kind of horsepower numbers you were getting with that 632cid engine with those 335cc AFR heads?---and what the top/peak RPM with the peak HP with the 335cc heads and the cam you were using???

Also, what kinds of "oiling issues" were you experiencing with your 632" engine?---Is it that problematic that you have to reduce your CID to a 598" ??? Are you planning on using the same block from the 632" for the 598" ???

I am very interested in the idea of a 632" for a marine application. Thanks

articfriends

iTrader: (1)

On dyno with dry headers will make about 820 hp at 6000/6200 and about 760 to 780 tq at about 5000. Your Etops and carb are both too small and will be determinig factor of what it actually makes in the boat. The 1 7/8 primary in your headers will be a choke point with the cu inches/cam/heads you have but we all have to work with some of the parts we already own on these boat builds, Smitty