Low Compression 331 Build?

awilli93coupe · Jan 26, 2016

331 build, Just curious about pricing mostly.
I'm using my 302 block, it's all ready bored over so I'm good on that. If I'm not mistaken the only machining I need is clearence for crank. But I will be rebuilding the top end too. I will be using quality streetable parts throughout the bottom and top end. Just hoping someone can help me with this that's been trough it and can recommend the good stuff and best steps! This will be a turbo car also! Any advice and info would be much appreciated.

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A5literMan · Jan 27, 2016

Just a FYI the block is only good to around 450-500rwhp before it will crack. Some run for awhile and some break quickly. The mains webbing is very thin/weak. A stud girdle(the popular thought) won't increase the durability or strength. I would recommend just using a cast steel crank and I beam rods with a good forged piston(Scat has a good reputation). An expensive forged assembly is wasted in a stock block, unless you are going to swap it into an aftermarket block(dart,boss). You will need to take the assembly to a good machine shop and have it balanced.

Have you assembled a motor before? If not I would recommend checking out ford Strokers.com. It's a engine builder site but he also has a video archive of how to's. It does cost some money to subscribe but is well worth it. Also buy some manuals and you may need to purchase a few extra tools,etc. Just remember to check and recheck measurements and keep everything clean. Dirt/lint etc will kill!

As far as topend parts,turbo system,fuel etc. what are your plans? I recommend going with either trick flow specialties or AFR for heads. I prefer the tfs 11r heads and for your motor would go with a 205cc runner. Buying the best parts you can in this category is a big plus. The fitment/quality of turbo systems/heads is a "you get what you pay for". Cheaper systems have more problems/require more "massaging", less durability and/or make less power.

awilli93coupe · Jan 27, 2016

A5literMan said:
Just a FYI the block is only good to around 450-500rwhp before it will crack. Some run for awhile and some break quickly. The mains webbing is very thin/weak. A stud girdle(the popular thought) won't increase the durability or strength. I would recommend just using a cast steel crank and I beam rods with a good forged piston(Scat has a good reputation). An expensive forged assembly is wasted in a stock block, unless you are going to swap it into an aftermarket block(dart,boss). You will need to take the assembly to a good machine shop and have it balanced.

Have you assembled a motor before? If not I would recommend checking out ford Strokers.com. It's a engine builder site but he also has a video archive of how to's. It does cost some money to subscribe but is well worth it. Also buy some manuals and you may need to purchase a few extra tools,etc. Just remember to check and recheck measurements and keep everything clean. Dirt/lint etc will kill!

As far as topend parts,turbo system,fuel etc. what are your plans? I recommend going with either trick flow specialties or AFR for heads. I prefer the tfs 11r heads and for your motor would go with a 205cc runner. Buying the best parts you can in this category is a big plus. The fitment/quality of turbo systems/heads is a "you get what you pay for". Cheaper systems have more problems/require more "massaging", less durability and/or make less power.

Thanks for all the help and I'll probably use a on3 kit and upgrade the turbo to maybe a precision or something high quality

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RangerJoe · Jan 27, 2016

331 kits with I beam rods normally need no clearancing. I have the scat 9000 series rotating assembly. It's a cast crank, 4340 I beams, and SRS pistons. The assembly is stronger than the stock block.

Honestly, if you are going turbo, I would just run a stock bottom end. If it's in good shape, it will outlast the block. Add a set of afr 165's or tfs twisted wedge heads, and you can make 500rwhp easily.

Joe

90sickfox · Jan 27, 2016

If you want to save a little money and put out more power than most grab a 351...393 stroker crank....302 pistons and crank the boost to 750hp. If I wouldve known I would've done it before building a 331 w/ TFS heads, h beam rods, xe282hr cam, and the all powerful block girdle....on a stock block. Smh

awilli93coupe · Jan 27, 2016

90sickfox said:
If you want to save a little money and put out more power than most grab a 351...393 stroker crank....302 pistons and crank the boost to 750hp. If I wouldve known I would've done it before building a 331 w/ TFS heads, h beam rods, xe282hr cam, and the all powerful block girdle....on a stock block. Smh

I also thought about goin with a351 and doin a 408 all motor

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A5literMan · Jan 27, 2016

awilli93coupe said:
I also thought about goin with a351 and doin a 408 all motor

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To be honest I wish I had held out and did this. A well built 408 can make as much or more hp/tq than a forced induction 302 build. Both are capable of 10sec et's and street driving. It would cost about the same, and be very dependable. You also don't have the under hood heat issues and other assorted potential problems. Also a 351 block is good to about 700rwhp if you wanted to upgrade. Now a T5 or stock automatic is not going to live very long behind either so plan an upgrade there as well.

awilli93coupe · Jan 27, 2016

A5literMan said:
To be honest I wish I had held out and did this. A well built 408 can make as much or more hp/tq than a forced induction 302 build. Both are capable of 10sec et's and street driving. It would cost about the same, and be very dependable. You also don't have the under hood heat issues and other assorted potential problems. Also a 351 block is good to about 700rwhp if you wanted to upgrade. Now a T5 or stock automatic is not going to live very long behind either so plan an upgrade there as well.

I might end up doing that I'm not sure yet, thanks for the advice tho

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madspeed · Jan 27, 2016

I second the 351 based swap

84Ttop · Jan 28, 2016

I say why not boost the 351 based motor???

awilli93coupe · Feb 1, 2016

84Ttop said:
I say why not boost the 351 based motor???

That would be insane

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Low Compression 331 Build?

awilli93coupe

Active Member

A5literMan

At least it is lumpy...

awilli93coupe

Active Member

RangerJoe

I leave the horn on while driving

90sickfox

Wasn't a pretty sight...and I've got big hands

awilli93coupe

Active Member

A5literMan

At least it is lumpy...

awilli93coupe

Active Member

madspeed

Colonel Mustard

84Ttop

They make new pistons every day, so why worry?

awilli93coupe

Active Member

Similar threads

Low Compression 331 Build?

Active Member

At least it is lumpy...

Active Member

I leave the horn on while driving

Wasn't a pretty sight...and I've got big hands

Active Member

At least it is lumpy...

Active Member

Colonel Mustard

They make new pistons every day, so why worry?

Active Member

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