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Zutz2v

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To carry on our conversion from earlier, which combo did you go with in your pistons? I’m trying to see which ones would lower my compression to pare up with my SC and a set of aggressive cams and my stock PI-heads


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asbenjamin101

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To carry on our conversion from earlier, which combo did you go with in your pistons? I’m trying to see which ones would lower my compression to pare up with my SC and a set of aggressive cams and my stock PI-heads


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How low u going. 9.1 ratio is still good for boost applications??

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Zutz2v

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Well I’m calling an engine builder on Tuesday cause it’s a long weekend. But essentially I need to know what I want. If I stayed with a stock compression would it hurt the performance all that much ? Cause if I decide to go N/A again k don’t want less compression
 

SecondhandSnake

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Lashes/ chain guides.
Pistons and rods ( should I bore and go bigger ?)
Cams
Valves/springs
Injectors
Main bolt studs ?
Am I missing anything else ?

Pistons- Depends on price range. Cheap is a 4032 piston, but they're less forgiving of detonation. An off the shelf 2618 piston like Manley, Diamond, or even JE is a good choice. If money is no object, Gibtecs offer even more advantage. Standard wrist pins will be fine. Stainless rings is probably overkill, and plasma/moly should be sufficient. I would pick a compression ratio in the low to mid 9s (in conjunction with the heads you have) if you're going to stick to pump gas.

Rods- Manley 4340 H-beams will certainly do the trick. Cheap and plentiful as 03/04 Cobra take outs. For a budget alternative, there's the Boss/Coyote rods. They don't leave as much margin as the H-beams though. ARP 8740 rod bolts are a very good idea.

Cams/valves/springs- that's always a loaded question. You have to pick your cam with your goals and head capabilities, and size springs accordingly. Ported or aftermarket heads will provide more potential and allow for higher RPM operation. And the tradeoff that bigger cams will make driveability down low suffer.

Injectors- 60lb/hr ones will do the trick for pump gas. E85 would be another discussion.

Main bolt studs/head studs- not necessary at this point in the build, but since the stock ones are TTY if you anticipate taking the engine apart and rebuilding another time or two, going ARP can provide a cost savings.

Timing system- Doesn't really require anything, though make sure you've got the metal timing guides and stamped reluctor wheel. Stock lash adjusters and followers are just fine.

Crank- Will your stock crank hold that power? Probably...but it's going to be close. A forged crank would be peace of mind. In a similar thought, now might be a good time to go with billet oil pump gears, or a GT500 pump with billet gears. Not necessary, but good insurance, especially if you're going to make a lot of power and turn high RPM.

For the bore I wouldn't go any bigger than I had to, and stick with stock stroke, unless you're trying to keep it very low RPM.
 

Zutz2v

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Pistons- Depends on price range. Cheap is a 4032 piston, but they're less forgiving of detonation. An off the shelf 2618 piston like Manley, Diamond, or even JE is a good choice. If money is no object, Gibtecs offer even more advantage. Standard wrist pins will be fine. Stainless rings is probably overkill, and plasma/moly should be sufficient. I would pick a compression ratio in the low to mid 9s (in conjunction with the heads you have) if you're going to stick to pump gas.

Rods- Manley 4340 H-beams will certainly do the trick. Cheap and plentiful as 03/04 Cobra take outs. For a budget alternative, there's the Boss/Coyote rods. They don't leave as much margin as the H-beams though. ARP 8740 rod bolts are a very good idea.

Cams/valves/springs- that's always a loaded question. You have to pick your cam with your goals and head capabilities, and size springs accordingly. Ported or aftermarket heads will provide more potential and allow for higher RPM operation. And the tradeoff that bigger cams will make driveability down low suffer.

Injectors- 60lb/hr ones will do the trick for pump gas. E85 would be another discussion.

Main bolt studs/head studs- not necessary at this point in the build, but since the stock ones are TTY if you anticipate taking the engine apart and rebuilding another time or two, going ARP can provide a cost savings.

Timing system- Doesn't really require anything, though make sure you've got the metal timing guides and stamped reluctor wheel. Stock lash adjusters and followers are just fine.

Crank- Will your stock crank hold that power? Probably...but it's going to be close. A forged crank would be peace of mind. In a similar thought, now might be a good time to go with billet oil pump gears, or a GT500 pump with billet gears. Not necessary, but good insurance, especially if you're going to make a lot of power and turn high RPM.

For the bore I wouldn't go any bigger than I had to, and stick with stock stroke, unless you're trying to keep it very low RPM.


So I spoke with the builder, I’m going Manley H rods and Manley pistons I believe. I’m leaving the compression stock in case I ever want to go back to N/A. I’m not looking to go past 500-550 RWHP so the stock crank is fine.

I’m going upgraded guides and lashes to the metal ones. APR head studs. I’m stayin with stock heads.

I’m also going to bore it .02 so nothing crazy. Not messing with the stroke.

as for cams I haven’t decided yet. I asked the builder what he’d recommend.

so I’m going with a pretty basic forge with the Intension of not going to crazy.

I will definitely look into getting a better oil pump. I can drop that in when I’m putting the motor back right ??
 

SecondhandSnake

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I will definitely look into getting a better oil pump. I can drop that in when I’m putting the motor back right ??

More or less. You have to have the timing chains and gear off to install it though. It bolts to the face of the block, around the crank snout. Then you put on all the timing components.
 

Zutz2v

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Just a bit of an update on my build.

Engine is getting bored .020 over
Cobra oil pump
Metal guides and tensioners
New chains
New water pump
Racing fuel pump
Bullet cams
New valves
Molar rods and pistons
Cobra crank
Longtube headers and catted X pipe
New APR bolts everywhere
New harmonic balancer
Bigger MAF
60LB injectors

I’m sure I’m missing stuff lol


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