Cylinder #8 fail... rebuild suggestions?

I had another thread trying to troubleshoot my pcv system for excessive blowby on my '13GT (followed by smoking exhaust) and have since learned my cylinder #8 is toast , and I thought I'd make a new thread asking for suggestions. Most of what I found on the forum search was old, especially with short block availability and pricing. I did a compression test (dry) and here are the results:

#1 - 165psi
#2 - 172psi
#3 - 165psi
#4 - 176psi
#5 - 175psi
#6 - 178psi
#7 - 160psi
#8 - 35psi

I really can't/don't want to throw $10-15k at the project, and was just wondering what the most cost effective (and maybe safe-er than with my gen 1??) options are for staying under 750whp as the goal? I was just about to convert to E85 and return style fuel system with dual pumps before all of this, so I'll be doing that after it's all said and done as well. I've learned from the other thread that it may be a good option for me to get a gen 2 short block and reuse my gen 1 heads and timing components (and everything else I already have...kooks headers, accessories, procharger kit, etc.). Can/should I use the stock gen 2 short block for < 750whp, or should I get a forged short block? I've read some threads with people getting a gen 2 short block for $1800 (https://www.svtperformance.com/threads/forged-short-block-what-did-you-guys-do.1161295/page-3) , but I'm having no luck finding it for anywhere near that. I'm not in a rush, if that matters.

Also - I was tuned by Lund and running around 9-10 psi with the Procharger.

Thanks in advance for any help/advice!

stock gen 2 shortblock and re use the gen 1 heads. 750hp easy. people have pushed those blocks to 900hp. just make sure you upgrade your oil pump gears to billet ones

Get the gen 2 short block and enjoy. In the past few months the price has gone up a few hundred, you should be able to easily find these for 2000-2200 plus your 500 dollar core fee.

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Riddick said:

Get the gen 2 short block and enjoy. In the past few months the price has gone up a few hundred, you should be able to easily find these for 2000-2200 plus your 500 dollar core fee.

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Do you know where can I find a short block for that price? The best I could find was Tasca for $3289 plus a higher core charge of $1500.
2015-2017 Ford Mustang Short Block FR3Z-6006-K | TascaParts.com

I've tried to research all the cylinder 8 failures and determination if there's a consensus on what the issue is, but it sure seems inconclusive. But if it was the rings or rod, are the gen2 components that much better? I just want to avoid another cylinder 8 failure or similar issue, if possible, and without spendinga small fortune. I was only supercharged for maybe 6 or 7k miles before this happened and wasn't even at 650whp.


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Wait for black Friday discounts.

Well poop on my parade. I just looked up these a few weeks ago and they were a touch over 2 grand. Crazy these shot up to over 3 grand . I planned on getting one of these and mad at myself for wanting to wait.

Riddick said:

Well poop on my parade. I just looked up these a few weeks ago and they were a touch over 2 grand. Crazy these shot up to over 3 grand . I planned on getting one of these and mad at myself for wanting to wait.

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Yeah man I've looked all over to no avail. For less than $3300 (plus core charge). Is this some Covid year pricing?

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Seeing as how this dang gen 2 short block is now $3300 and up, what do you guys think of something like this? Basically a lightly used crate engine w gen 2 shortblock with OPGs and ARPs and all gen 1 heads/accessories/timing components etc. This should be all setup for a 700whp car and is the price reasonable? (seems to be?)

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For 5500 I would build your existing short block with forged components and reuse your current heads

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Riddick said:

For 5500 I would build your existing short block with forged components and reuse your current heads

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Thanks for the feedback! I just wonder what the condition of my block is... if the rings broke apart (don't know yet) and if the heads are okay or not as well.

Also, while I'm fairly comfortable building from the short block on up, I have no experience putting one together from the bottom up with bare block. Generally speaking, how much experience is required or how difficult is the build of the rotating assembly?


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Anyone know anything about these AMS forged short blocks? Any good?

AMS Racing 1100 HP Rated Forged Ford 5.0L Coyote Short Block




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Stay away, they are local to me and I do not recommend. To many horror stories and there's a reason why noone local uses them.

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For the price it's hard to beat Livernois prices and what you get. This is about equivalent to a aluminator and the price is spot on. You can also get their pro series block for 5500 I believe.

Livernois Motorsports

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Riddick said:

For the price it's hard to beat Livernois prices and what you get. This is about equivalent to a aluminator and the price is spot on. You can also get their pro series block for 5500 I believe.

Livernois Motorsports

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Thanks for the feedback!! Anywhere else you might recommend looking for something similar?


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7Lemons said:

Thanks for the feedback!! Anywhere else you might recommend looking for something similar?


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Shaun at AED is starting to build engines again. From personal experience he is excellent. Check out this short block at $3,995....

AED Tuning

68gtscode said:

Shaun at AED is starting to build engines again. From personal experience he is excellent. Check out this short block at $3,995....

AED Tuning

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This is right up my alley! Would you suspect I have any head/valvetrain damage from the cylinder 8 failure? I know there's no way to tell until it's apart, but I'm just wondering what people have seen with all the cylinder 8 failures. I'd like to reuse them if I can.

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In the meantime take out the #8 plug and put a borescope in there. In addition to seeing the piston and bore, some of them come with little mirrors so you can at least see part of the head.

Coz said:

In the meantime take out the #8 plug and put a borescope in there. In addition to seeing the piston and bore, some of them come with little mirrors so you can at least see part of the head.

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Yep actually I've done that and the valves look okay... I mean the exhaust valves look pretty dirty up inside when they're down but, but they otherwise look okay with the camera, from what I can see.

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7Lemons said:

This is right up my alley! Would you suspect I have any head/valvetrain damage from the cylinder 8 failure? I know there's no way to tell until it's apart, but I'm just wondering what people have seen with all the cylinder 8 failures. I'd like to reuse them if I can.

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Sorry, but I cannot provide useful insight here. From your other post, it sounds like you didn't see anything obvious in the scope. I assume all should be well but suppose you'll know for sure when you tear it down. I am not that familiar with the differences in Coyote variations, but assume you could find a used head, etc. if needed from a recycler. Anyhow, I would definitely give Shaun at AED serious consideration for the short block... He used to work on my cars when I lived in Northern California. While he's primarily known for his tuning ability, he's also an excellent engine builder with a lot of knowledge and extreme attention to detail.

Thanks for the reply, I am chatting with Shaun at AED about his short block now... I may go that route, still just weighing the options.