Mercruiser 454/330 questions
08-20-2003, 09:33 AM
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Mercruiser 454/330 questions
Anyone know the specs on a '91-ish Mercruiser 454/330?
Compression ratio?
Piston, crank, rod type? (Forged, cast, hypereutectic)
Cylinder head intake runner volume (I assume they are oval port)
Cylinder head chamber volume
Thanks.
Compression ratio?
Piston, crank, rod type? (Forged, cast, hypereutectic)
Cylinder head intake runner volume (I assume they are oval port)
Cylinder head chamber volume
Thanks.
08-20-2003, 10:25 AM
#2
Monty,
I'm not exactly sure on the comp ratio maybe 8.7:1
cast crank
rods are 3/8'' rod bolts
cast pistons
GM oval port "peanut port" heads not sure of the port runner volume---probably close to 235cc or so.
2.06" intake valves and 1.72" exhaust valves
combustion chamber volume is between 119-121cc
Perhaps someone else can jump in and help out on the specs---I'm just going by memory.
I know you were only asking for engine specs on the Merc 330, but in case you were looking to upgrade here are some things that I have seen and experienced in relationship to the Merc 330....
My cousin had a pair of 330's that he upgraded by adding the 2.19" intake valves, 1.85" exhaust valves, pocket/bowl porting on the heads, bore notching on the cylinders, a flat tappet hydraulic cam of about 218*/226* on 110* lobes, 8.6:1 comp ratio, dual plane aluminum high rise intakes manifolds, Holley carb and with dyno headers they made 461hp @ 5100rpm and 510ftlbs of torque. He removed the stock Merc cast iron junk exhaust manifolds will be installing GIL exhausts manifolds. He didn't want to buzz the engines up much beyond 5000rpm because of all the cast components and he pretty much achieved his goal and made awesom power and torque from a Merc 330hp base engine without going too wild parts and maintaining the same head castings. Another friend of mine had a little bit larger of a flat tappet hydraulic cam with Merlin oval port heads with big valves, same intake manifold, same carb, same comp ratio and he made 505hp @5400rpm and 514ftlbs of torque on the SAME dyno!
So unless you need 45 more HP, you can stay with the GM heads that you already have and still make make real good torque for cheaper $$$----and torque is really want you want in a good boat engine. Hope this has helped you a bit.
I'm not exactly sure on the comp ratio maybe 8.7:1
cast crank
rods are 3/8'' rod bolts
cast pistons
GM oval port "peanut port" heads not sure of the port runner volume---probably close to 235cc or so.
2.06" intake valves and 1.72" exhaust valves
combustion chamber volume is between 119-121cc
Perhaps someone else can jump in and help out on the specs---I'm just going by memory.
I know you were only asking for engine specs on the Merc 330, but in case you were looking to upgrade here are some things that I have seen and experienced in relationship to the Merc 330....
My cousin had a pair of 330's that he upgraded by adding the 2.19" intake valves, 1.85" exhaust valves, pocket/bowl porting on the heads, bore notching on the cylinders, a flat tappet hydraulic cam of about 218*/226* on 110* lobes, 8.6:1 comp ratio, dual plane aluminum high rise intakes manifolds, Holley carb and with dyno headers they made 461hp @ 5100rpm and 510ftlbs of torque. He removed the stock Merc cast iron junk exhaust manifolds will be installing GIL exhausts manifolds. He didn't want to buzz the engines up much beyond 5000rpm because of all the cast components and he pretty much achieved his goal and made awesom power and torque from a Merc 330hp base engine without going too wild parts and maintaining the same head castings. Another friend of mine had a little bit larger of a flat tappet hydraulic cam with Merlin oval port heads with big valves, same intake manifold, same carb, same comp ratio and he made 505hp @5400rpm and 514ftlbs of torque on the SAME dyno!
So unless you need 45 more HP, you can stay with the GM heads that you already have and still make make real good torque for cheaper $$$----and torque is really want you want in a good boat engine. Hope this has helped you a bit.
Last edited by KAAMA; 08-20-2003 at 10:28 AM.
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08-21-2003, 08:44 AM
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Cranks, rods are usable and reliable for around 500 horsepower and 5200-5500 rpms. There are a lot of people running upgraded 330 Mercs with great success. Don't let anyone tell you different.
08-21-2003, 09:10 AM
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I'm sure they are fine, I was just kidding. I just prefer the 7/16" rods and forged pistons.
If I don't go with 502's, I'm going to rebuild the 454's with Crower billet rods and forged crank with JE forged pistons.
If I don't go with 502's, I'm going to rebuild the 454's with Crower billet rods and forged crank with JE forged pistons.
09-30-2013, 08:32 PM
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Monty,
I'm not exactly sure on the comp ratio maybe 8.7:1
cast crank
rods are 3/8'' rod bolts
cast pistons
GM oval port "peanut port" heads not sure of the port runner volume---probably close to 235cc or so.
2.06" intake valves and 1.72" exhaust valves
combustion chamber volume is between 119-121cc
Perhaps someone else can jump in and help out on the specs---I'm just going by memory.
I know you were only asking for engine specs on the Merc 330, but in case you were looking to upgrade here are some things that I have seen and experienced in relationship to the Merc 330....
My cousin had a pair of 330's that he upgraded by adding the 2.19" intake valves, 1.85" exhaust valves, pocket/bowl porting on the heads, bore notching on the cylinders, a flat tappet hydraulic cam of about 218*/226* on 110* lobes, 8.6:1 comp ratio, dual plane aluminum high rise intakes manifolds, Holley carb and with dyno headers they made 461hp @ 5100rpm and 510ftlbs of torque. He removed the stock Merc cast iron junk exhaust manifolds will be installing GIL exhausts manifolds. He didn't want to buzz the engines up much beyond 5000rpm because of all the cast components and he pretty much achieved his goal and made awesom power and torque from a Merc 330hp base engine without going too wild parts and maintaining the same head castings. Another friend of mine had a little bit larger of a flat tappet hydraulic cam with Merlin oval port heads with big valves, same intake manifold, same carb, same comp ratio and he made 505hp @5400rpm and 514ftlbs of torque on the SAME dyno!
So unless you need 45 more HP, you can stay with the GM heads that you already have and still make make real good torque for cheaper $$$----and torque is really want you want in a good boat engine. Hope this has helped you a bit.
I'm not exactly sure on the comp ratio maybe 8.7:1
cast crank
rods are 3/8'' rod bolts
cast pistons
GM oval port "peanut port" heads not sure of the port runner volume---probably close to 235cc or so.
2.06" intake valves and 1.72" exhaust valves
combustion chamber volume is between 119-121cc
Perhaps someone else can jump in and help out on the specs---I'm just going by memory.
I know you were only asking for engine specs on the Merc 330, but in case you were looking to upgrade here are some things that I have seen and experienced in relationship to the Merc 330....
My cousin had a pair of 330's that he upgraded by adding the 2.19" intake valves, 1.85" exhaust valves, pocket/bowl porting on the heads, bore notching on the cylinders, a flat tappet hydraulic cam of about 218*/226* on 110* lobes, 8.6:1 comp ratio, dual plane aluminum high rise intakes manifolds, Holley carb and with dyno headers they made 461hp @ 5100rpm and 510ftlbs of torque. He removed the stock Merc cast iron junk exhaust manifolds will be installing GIL exhausts manifolds. He didn't want to buzz the engines up much beyond 5000rpm because of all the cast components and he pretty much achieved his goal and made awesom power and torque from a Merc 330hp base engine without going too wild parts and maintaining the same head castings. Another friend of mine had a little bit larger of a flat tappet hydraulic cam with Merlin oval port heads with big valves, same intake manifold, same carb, same comp ratio and he made 505hp @5400rpm and 514ftlbs of torque on the SAME dyno!
So unless you need 45 more HP, you can stay with the GM heads that you already have and still make make real good torque for cheaper $$$----and torque is really want you want in a good boat engine. Hope this has helped you a bit.
"ICU looking" shared this with me and it got me interested since I already have SM exhaust with long risers...
08-21-2023, 01:15 PM
#8
Bringing back this old thread to see if anybody can pitch in based on more recent experience , I was always told that 330's were not worth trying to upgrade into higher hp.
"ICU looking" shared this with me and it got me interested since I already have SM exhaust with long risers...
"ICU looking" shared this with me and it got me interested since I already have SM exhaust with long risers...
08-25-2023, 12:26 AM
#9
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I am also interested as to the results of this thread as I am looking to upgrade my engine to make more power, as well as possibly significantly lighter and more efficient with aluminum heads, exhaust, and a hydraulic roller cam.
By the way, the Gen V marine 454 had a cast steel crank, cast aluminum pistons, and forged rods. It had peanut port heads and a non-adjustable flat tappet cam and valvetrain. My "Performance Tuned" version has the aluminum high-rise "Mag" dual-plane intake and 750 CFM Weber square-bore carb.
By the way, the Gen V marine 454 had a cast steel crank, cast aluminum pistons, and forged rods. It had peanut port heads and a non-adjustable flat tappet cam and valvetrain. My "Performance Tuned" version has the aluminum high-rise "Mag" dual-plane intake and 750 CFM Weber square-bore carb.
