Chevy 496/Volvo Penta 8.1 Heads

[SHU-DOG]

OK I am having trouble trying to find if the 496 Chevy truck heads are the same(intake/exhaust valve sizes/springs/etc) size and are an exact swap to the Volvo Penta 8.1 GXi marine motor.

My Volvo Heads have one side with broken springs, bent rods and a bent valve or two.

Trying to find the easiest way to fix-take out and fix or simply swap to a new head.

Any marine mechanics here?

Thanks Kevin

 

[fun2xlr8]

Dude, nothing is the same between those two motors. Sorta like asking if Chevy 1500 and Dodge 1500 body parts are interchangable. Same size truck, right? Anyway, the answer is No, you gotta spend the big bucks for the Penta shit bro.

Greg

 

[SHU-DOG]

Dude, nothing is the same between those two motors. Sorta like asking if Chevy 1500 and Dodge 1500 body parts are interchangable. Same size truck, right? Anyway, the answer is No, you gotta spend the big bucks for the Penta shit bro.

Greg

They shouldn't be that much different though. GM makes the engine then sends them to Volvo Penta for their own EFI, cooling, etc.

Just as Dodge SRT send its engines to Illmor for them to Marinize.

We should be able to swap out heads with the Illmore stuff(if we wanted to pay big $ for it).

I can't see them having a different block, heads and bolt patterns etc.

Anyone know for sure??????????? :dontknow:

 

[FSTJACK]

Call Brett Bostich at NuTech custom machine in Lakeside. He does a lot of HP marine engine stuff and may have what you need. or can send you in the right direction. Tell him Jack O'Donnell told you to call.

619-561-9826

 

[fun2xlr8]

Your only real answer is to call Volvo Marine. I would be willing to bet that they do some metal work to the heads AND block. Otherwise, why would the engine price be so drasticly different? I know for a fact they did that to the old Penta 5.7s, so I am sure they still do that now on the late model big blocks. These engines are designed and beefed up to run at full throttle for long periods of time. The cylinder walls would need to be thickened and the heads would need some filling at thin areas as well. Otherwise, the constant full throttle operation would crack them easily. Sure, the cold water being run through the motor helps to cool it more quickly, but the walls still need to be thicker to handle the higher internal temps of running full throttle. I COULD be wrong, but I wouldn't bet money against me.

Greg

 

[SHU-DOG]

Call Brett Bostich at NuTech custom machine in Lakeside. He does a lot of HP marine engine stuff and may have what you need. or can send you in the right direction. Tell him Jack O'Donnell told you to call.

619-561-9826

Once again Jack U dah Man.

I gottah fix the heads and just figured i could swap out some heads from a 8.1 chevy truck that a guy around the corner had the crank bearing go bad on. Too cheap not to even try. I may upgrade the springs and rockers.

Thanks Kevin

 

[Rockin Ronnie]

Actually I don't know what type of boat it's in but, it's less expensive and more fun to swap it out for a GM crate motor and then take the parts off of your 8.1 such as alternator, waterpump etc and go from there. Depending on the application this can actually be a better way to go. We have built alot of hypo motors for boats, My friend Gordon has an 800 hp bench dynoed 502 merlin crate motor that we run in his 28 ft cougar that GPS, D at 113 on pump fuel..Check with the boys at CP Performance in Cali and they can give you good advice on the best way to proceed from here without breaking your wallet!!

 

[SHU-DOG]

Actually I don't know what type of boat it's in but, it's less expensive and more fun to swap it out for a GM crate motor and then take the parts off of your 8.1 such as alternator, waterpump etc and go from there. Depending on the application this can actually be a better way to go. We have built alot of hypo motors for boats, My friend Gordon has an 800 hp bench dynoed 502 merlin crate motor that we run in his 28 ft cougar that GPS, D at 113 on pump fuel..Check with the boys at CP Performance in Cali and they can give you good advice on the best way to proceed from here without breaking your wallet!!

Nah. The heads will be under $1K. New engine will be over $4K easy. Plus the cost to install.

No I think i will try and do myself and swap out the heads then either fix mine or just sell them.

Forgot to add that it is a 24' Pantera