5.7 Volvo Penta GS Intake, Carb, Heads & Cam

[USA_boater]

If it were me I'd do the 4bbl carb, Edelbrock intake, and 1.6 roller rockers...if the vortec heads will work (if not already vortec in '97), then perhaps I'd also consider them as the flow much better than the old TBI truck heads which is probably what is on that boat? But I'm lazy and cheap...if you have the money and time you can do about anything! But bang for the buck and time, I think a minor top-end upgrade and maybe an Accel coil, brass cap & rotor, HP plug wires, etc. might give u that seat of the pants gain you want.

Did you add the through hull? What brand is it? How much did it cost?

 

[TNParrothead]

Thanks for all of the knowledgeable info guys. You all are helping me out more than you know. I have another question. I called Comp Cams today and the guy is wanting to know my compression ratio. I have no idea what it is. Also, I pulled my heads last night. I noticed something I thought was odd. Maybe not. Anyways, the heads have two different casting numbers. Not my Vortec heads, the factory heads. # 14096217 and # 4080217. Is this normal ?

 

[USA_boater]

I do not have the answer but I will be interested to see what it is. I know some of the old TBI & carbed trucks had 76cc heads and 8.5:1 compression. But some of the 350's also had 64cc heads and the corvettes may have had 58 or 60cc...

My point is, we always hear about how marine engines need more horse power and run on super unleaded, etc. yet (sometimes in the same conversation like this thread) we hear how they need to be low-end torque monsters and more like a truck motor. If I had to guess you'd have the 64cc heads which would make it like 9.25:1 (going on memory), but it is possible if the marine stocker truck engine theory is true, then it could be the 8.5:1 motor.

Does your manual say it requires premium fuel?

Now we wait for Scott or one of the others who knows to answer

 

[alldodge]

Somebody has been messing with the motor and has probably been replaced
The 14096217 shows 1955 to 1986
Think the 4080217 is a mis-cast number, assume both are the same


14096217...55-86...350..........Crate motor, 285hp/300hp, 64cc chambers, 72' or 90' center intake manifold bolt angles

 

[TNParrothead]

So if they are 64cc heads does that mean it’s the 9.25:1 ratio ? Would there be a for sure way to tell ? Yes it does call for premium.

 

[TNParrothead]

Also, as far as someone putting a head on it or something, I don’t think that’s the case. I guess it’s possible, but if they did they repainted the whole motor. It’s still the charcoal and the bolts have never had a wrench on them.

 

[Scott Danforth]

as AD posted
14096217...55-86...350..........Crate motor, 285hp/300hp, 64cc chambers, 72' or 90' center intake manifold bolt angles not sure what you have for a motor. FYI - Volvo used those heads on the AQ271's in the mid 80's and those were rated at 9.4:1 CR and used 87 octane. a set of vortec heads would be an improvement and wouldnt affect CR

 

[TNParrothead]

Finally got a little more info on my motor. The casting is #10243880....5.7LG SGI....apparently this is a roller block. I still don’t know the compression ratio. I’m hoping some of you guys might have more info for me with these numbers. Thanks !

 

[alldodge]

That one is

10243880...350...95-00...2 or 4...Vortec truck, Gen.I crate motors and "ZZ4", roller cam, one piece rear seal

I think you're trying to find the CR for the wrong reason, you have a stock motor, this on should be 8.3

Comp Cam (not my first choice) needs to know the CR to determine which cam they would suggest based on what your building. If your going to rebuild the motor, then need to decide if your boring, changes to head, deck the block. What ever is done to the block/heads changes the CR

 

[aimlow]

Finally got a little more info on my motor. The casting is #10243880....5.7LG SGI....apparently this is a roller block. I still don’t know the compression ratio. I’m hoping some of you guys might have more info for me with these numbers. Thanks !

The last Volvo I disassembled was a roller block with a flat tappet cam, dished pistons, non-vortec center bolt heads.