Marine Cam & Heads
05-06-2019, 01:26 PM
#1
Marine Cam & Heads
Hi guys, I have been browsing these forums for a little while, but this is my first post. I have a new to me 1990 C4, with the L98. I am looking at some performance modifications. I have headers, full exhaust, K&N filter etc. I have some questions regarding cylinder heads and camshafts.
I have a set of repellent condition marine heads with the casting number 059 stamped. From my understanding these are Vortec style heads, that should flow pretty well, maybe not as good as the 062 Vortecs. I also have the camshaft from this motor. The reason I am trying to use all of this, is because the parts were free. My question is has anyone had experience, or what are your thoughts on this. The only specs I can find on the camshaft, is below.
I have a set of repellent condition marine heads with the casting number 059 stamped. From my understanding these are Vortec style heads, that should flow pretty well, maybe not as good as the 062 Vortecs. I also have the camshaft from this motor. The reason I am trying to use all of this, is because the parts were free. My question is has anyone had experience, or what are your thoughts on this. The only specs I can find on the camshaft, is below.
05-06-2019, 03:37 PM
#5
Here are also some flow numbers on the heads. It appears the 059 has a smaller intake valve, but the numbers seem to flow better?
I got these numbers from this site.
http://users.erols.com/srweiss/tablehdc.htm#Chevy
I got these numbers from this site.
http://users.erols.com/srweiss/tablehdc.htm#Chevy
05-06-2019, 03:39 PM
#6
Thanks for the help Kevova, I actually work at a marine dealership, the parts came from a boat with a frozen block. The motor is a clockwise rotation.
05-06-2019, 03:40 PM
#7
Team Owner
Pro Mechanic
Only Direct drive inboards had reverse rotation. All Stearn drive use regular rotation.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo.
4. That cam looks pretty lame.
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo.
4. That cam looks pretty lame.
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it.
05-06-2019, 03:56 PM
#8
Only Direct drive inboards had reverse rotation. All Stearn drive use regular rotation.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier. - Yes, I am aware of this, but any aluminum performance heads are big $$, even if I bought new heads, they would most likely be iron.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there. - Yes I am aware of this as well, I was figuring on if this worked it would still be considerably less than a set of performance heads.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo. Thank you, this is exactly the type of information I'm looking for.
4. That cam looks pretty lame. Again, good information, thank you!
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it. I gave up most machine/fab work a long time ago. Mechanical sure, but I'm not good enough at this type of work to justify doing it myself.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier. - Yes, I am aware of this, but any aluminum performance heads are big $$, even if I bought new heads, they would most likely be iron.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there. - Yes I am aware of this as well, I was figuring on if this worked it would still be considerably less than a set of performance heads.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo. Thank you, this is exactly the type of information I'm looking for.
4. That cam looks pretty lame. Again, good information, thank you!
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it. I gave up most machine/fab work a long time ago. Mechanical sure, but I'm not good enough at this type of work to justify doing it myself.
05-06-2019, 04:25 PM
#9
Only Direct drive inboards had reverse rotation. All Stearn drive use regular rotation.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo.
4. That cam looks pretty lame.
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo.
4. That cam looks pretty lame.
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it.
05-06-2019, 04:45 PM
#10
Team Owner
Pro Mechanic
I guess I'd look for used heads.
I guess I'd consider 350/L31 Vortec heads....but adding weight and then paying for a new lower? I don't think that I could convince myself to move on that.
I don't know where your priorities fall, but you could get some 350 Vortec heads cheap (you can get them at pick 'n pull yards here for about $35/head) and then double stack intake gaskets, keep your lower and get 15-20hp for less than $100 bux. I guess that would be a thing I could maybe talk myself into...since the investment is so low.
Cam? I'd search the classifieds for a used roller cam of about the right size. For ME, on a stock TPI that would be in the 2-teens duration.
I guess I'd consider 350/L31 Vortec heads....but adding weight and then paying for a new lower? I don't think that I could convince myself to move on that.
I don't know where your priorities fall, but you could get some 350 Vortec heads cheap (you can get them at pick 'n pull yards here for about $35/head) and then double stack intake gaskets, keep your lower and get 15-20hp for less than $100 bux. I guess that would be a thing I could maybe talk myself into...since the investment is so low.
Cam? I'd search the classifieds for a used roller cam of about the right size. For ME, on a stock TPI that would be in the 2-teens duration.
05-06-2019, 11:24 PM
#11
Le Mans Master
Only Direct drive inboards had reverse rotation. All Stearn drive use regular rotation.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo.
4. That cam looks pretty lame.
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo.
4. That cam looks pretty lame.
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it.
Anyway, everything you said
05-06-2019, 11:31 PM
#12
Team Owner
Pro Mechanic
Huh. I learned a thing. Who brought that out? OMC?
05-07-2019, 02:29 PM
#13
Le Mans Master
05-08-2019, 02:35 PM
#15
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St. Jude Donor '05
Porting what you have is a good idea, they arent horrible.
Factory castings leavea lot to be desired so most anything will pick them up lol!
Factory castings leavea lot to be desired so most anything will pick them up lol!
05-10-2019, 11:25 AM
#16
Burning Brakes
Member Since: Oct 2017
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Only Direct drive inboards had reverse rotation. All Stearn drive use regular rotation.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo.
4. That cam looks pretty lame.
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it.
I see a few problems with this plan:
1. IF those are Vortec heads, they'll be iron, so heavier.
2. You'll also need a Vortec specific lower intake manifold which will run you $4-500. So "Free" goes away, there.
3. If those are head for a 305, they're smaller combustion chamber and may be too high compression ratio for your car/combo.
4. That cam looks pretty lame.
If it were ME, and I were on a 'free' budget, I'd hand port my stock '90 heads and throw a used cam and/or rockers at it.
That cam sheet is worthless imho, it doesnt list duration, overlap (which it wont have any because it's a marine cam) or valve timing. Save your money for better parts.
05-11-2019, 02:05 PM
#17
305 heads also have smaller valves that are needed to clear the smaller bore. I wouldn't bother with them.
That cam sheet is worthless imho, it doesnt list duration, overlap (which it wont have any because it's a marine cam) or valve timing. Save your money for better parts.
That cam sheet is worthless imho, it doesnt list duration, overlap (which it wont have any because it's a marine cam) or valve timing. Save your money for better parts.
https://www.flotekheads.com/store/Sm...4cc-p130678684
05-11-2019, 08:15 PM
#19
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St. Jude Donor '05
Limitmed by the guide. with someone who knows they can be picked up big time with a little :wink
Last edited by cv67; 05-11-2019 at 08:16 PM.
05-11-2019, 09:09 PM
#20
Le Mans Master
