Reply With QuoteCFM, the cam specifications are as follows:
Comp Cams Part # 01-456-8
Grind # XM296HR
Duration @ .050"
Intake 242
Exhaust 248
Lift Intake and Exhaust
.566
He removed GM '088's . These are what....around 325cc intake runners ? 2.19 , 1.88 valves ? Old tech runner and combustion chambers ?
I'm still lost in why people, and now you added to that list, think the Dart Pro One 310's are not a good addition.
I'm not saying this poking fingers, I'm actually confused why people think these 310 Pro One's are the wrong choice. Or am I taking it this way and you guys are actually talking about something else ?
There are many stock shortblock 502's with 119cc chamber AFR 315's and 305's / Dart Pro One 310's / Canfield 310's (all produce around 8.75:1 compression of course) that are absolutely steam rolling out there. IE: making big power. RPM's are typically being used around 5400-5800rpm depending on cam.
We know everything but the cam he has, so i guess I'll try to figure out what he may has.
My bad...I was thinking he took off some oval ports. These heads should have stepped it up some. (Although I would have gone with the Canfields in a heart beat) This just confirms what I'm saying all along, though. Without flowing the heads and getting the right cam, this thing's just going to continue to be a dog. My guess is it's going to be in the .625-.630 range, in the low 260's.
CFM, the cam specifications are as follows:
Comp Cams Part # 01-456-8
Grind # XM296HR
Duration @ .050"
Intake 242
Exhaust 248
Lift Intake and Exhaust
.566
not a bad candidate for some forced induction or super charged.
caribbean20, the zz502 does have the 9.6:1 compression, but that is with the GM aluminum heads (made by edelbrock) with a 110cc. with the 119cc heads you have you are at about 8.75:1. i think you are on the right track in bumping the compression if you plan to stay N/A. i think it is there were you are limited. the cam you have is allready IMHO a bit too much for that low compression. but with the 110cc bumping it up to 9.6:1, and maybe some mild bowl work to the heads, i think it would be a decent cam. a little less duration would be my choice in such a large boat, but thats just me.
Steel, thanks for the reply and I get it. I'm "starting in the middle" out of necessity, iron heads broke so I just ponied up for alloy. No big deal, I'm not dissapointed, boat runs fine now, just wanted to make sure I wasn't missing something obvious.
As for the 5 step program or any part thereof, my challenge is I have to do everything from a distance with my wallet and telephone. Live in south bay, boat stays in Vegas, I know of no reputable builders there. Pain in the arse to haul boat back here, find storage, take boat back.
Best advice anyone can give me now is the name of a good boat motor shop with dyno in Vegas. Absent that, 2 road trips ensue or I just leave well enough alone.
Lawless Engines - Brett Bergeron (no relation to the bergeron's in pheonix)
6845 Speedway blvd. Ste. K
Las Vegas, Nv. 89115
702-644-5543
He isn't the cheapest but the work i've been getting from him is great. Most all of his equipment is CNC stuff.
not a bad candidate for some forced induction or super charged.
caribbean20, the zz502 does have the 9.6:1 compression, but that is with the GM aluminum heads (made by edelbrock) with a 110cc. with the 119cc heads you have you are at about 8.75:1. i think you are on the right track in bumping the compression if you plan to stay N/A. i think it is there were you are limited. the cam you have is allready IMHO a bit too much for that low compression. but with the 110cc bumping it up to 9.6:1, and maybe some mild bowl work to the heads, i think it would be a decent cam. a little less duration would be my choice in such a large boat, but thats just me.I would agree in a prop boat, but not in a jet. (at 10:1)
JMO
I just looked up some flow numbers on the Pro One 310's and ran some numbers. For your AB impeller to spin 5500, you need about 475-480hp @ the impeller.
These are just some ballpark numbers according to some ghetto math I learned a while back.
For a (hypothetical) max rpm of 6000, at 242*@.05 you need a calculated 324cfm which is about .425" lift, according to the flow numbers I have. That's for max rpm.
For peak Q at 5000, with a duration of 230*@.05, you're looking at about 285cfm, or about .325" lift. Add to that .100" for the actual lift you'd be looking at, so ideally you're in the .425 lift area, at 230*@.05. You can play around with the duration numbers to get your rpm where you want it, but that's basically where your intake should be for a peak torque near 5000, and a max rpm of 6000.
Since your ex at that lift is about 72% of the intake, using these numbers, your ex lift would be about .415, and the duration would be about 232. My thinking is that with a fairly large cubic inch, and these heads, in the rpm range youre going to run, you'll be closer to the 220* range and high 500" lift range.
Port flow is decent on the Darts at that lift, but the velocity is down. By these numbers it seems these heads are a little on the big side for this engine at this rpm range, but remember, these are just guide lines, and there's a lot more to a cam than just this (and a lot I still dpn't understand). These heads should support between 500-600 hp at that range. Maybe someone with a DTD can get you an estimated HP number.
Keep the engine together. Your already pretty happy with the speed. If the thing doesnt leak or burn oil or somthing theres no reason to snap the heads, have them "FLOWED" so you can match some special cam to them and say thats the ultimate combo. Your engine is already limited to the parts you have chosen. Just dyno the engine, if the dude on the lever is sharp he will guide you through many pulls and you will be close to your 600 hp figure. Even the perfect cam for your combo probably wouldnt make much past 600hp below 5500-6000 anyway.
I would agree in a prop boat, but not in a jet. (at 10:1)
JMO
he is not at 10:1. with the 119cc heads, the 502 is at about 8.75:1
he is not at 10:1. with the 119cc heads, the 502 is at about 8.75:1Right...I was referring to when he bumped up the CR as he said he's going to. Guess I could have clarified that. Besides, those heads flow a little better than I was thinking, and after looking at the numbers, I might agree with you on the duration.
Keep the engine together. Your already pretty happy with the speed. If the thing doesnt leak or burn oil or somthing theres no reason to snap the heads, have them "FLOWED" so you can match some special cam to them and say thats the ultimate combo. Your engine is already limited to the parts you have chosen. Just dyno the engine, if the dude on the lever is sharp he will guide you through many pulls and you will be close to your 600 hp figure. Even the perfect cam for your combo probably wouldnt make much past 600hp below 5500-6000 anyway. I'd be pretty disappointed if my roller cam'd 502 with Dart heads topped out under 400hp. I'd have that thing apart and asking questions in a heart beat. Obviously his combination sucks as is. (sorry, no offense) 600 hp would spin that AB right around 5900 rpm. Think he'd be happy then?
Your engine is already limited to the parts you have chosen. I think that's the whole point.
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