Injector Limit for Cast Oval Bowl Pistons???

[Grimes_County LBZ]

Also posted this in the LBZ forum, but figured I throw it in here too since this is a build forum.

Picked up a stock LB7 short block recently for my LBZ project truck. Intend to build this utilizing a forged SOCAL crank and forged carillo rods, but want to use cast piston to get some more longevity out of the engine. Curious to see if anyone knows how much injector the Finger's Oval Bowls will take? Could I get away with 60% over's, 100% overs? Bigger? Just looking for some guidance.

To provide a little more info, because I know this question is dependent on a lot of variables... intend to top it off with a set of PPE cast iron heads, and likely a Ryan's 64mm 9 blade. May consider a compound setup in the future, but we'll cross that bridge when we get there. Already have a built trans.

I look forward to the replies. Thanks in advance for the support.

-Shane

 

[TheBac]

Sorry, that duplicate thread is gone. No need for multiple threads in different sections for the same topic.

From what I understand, Jon's ovals can handle just about anything injector-wise you can throw at them. Im sure Brad or someone else who's been north of 1000hp will stop and back that.

 

[N2BRK]

I know I’ve read 1700hp on this site. Not sure on the injectors - might have been 500 over. Best to use the search!

 

[Grimes_County LBZ]

Sorry, that duplicate thread is gone. No need for multiple threads in different sections for the same topic.

From what I understand, Jon's ovals can handle just about anything injector-wise you can throw at them. Im sure Brad or someone else who's been north of 1000hp will stop and back that.

@TheBac thanks for the reply! That seems like way more than what I'm looking to make, but at that power level, I would assume 150% over injectors at a minimum. Should be plenty strong enough to do what I need. Thanks again.

 

[malibu795]

@TheBac thanks for the reply! That seems like way more than what I'm looking to make, but at that power level, I would assume 150% over injectors at a minimum. Should be plenty strong enough to do what I need. Thanks again.

60s with a 10mm pump will most likely max a 64mm charger out and should put you safely in the 600hp range

 

[Chevy1925]

Fingers pistons have gone into the 2k range with no issue iirc.

100% overs on a single 64 is a good route. Leaves room to grow for compounds. Tbh, a 1500uS tune on a single 64 and 100% overs will be smokey. Add a compound and its going to make another 100hp on the same tune just from cleaning up the smoke

 

[2004LB7]

My recollection is that John said no one has really found the upper limit of his pistons. Basically a rod, crank or something else failed before the piston when pushed. I think the only real failures where form something like a stuck injector torching the piston or other hardware failure hurting it. But none has outright failed on their own.

 

[N2BRK]

I’m surprised that no one has opined about the cast iron heads and 9 blade. ? Getting soft around here ?

 

[MarkBroviak]

I’m surprised that no one has opined about the cast iron heads and 9 blade. ? Getting soft around here ?

Honestly not any real world info on the cast iron heads in a street truck that I have even seen or heard of. Everyone I know that tried to get a set of them couldn't even get them. The 9blade turbine, sound and performance is awesome but reliability is yet to be proven good yet. For the question asked about what injector size for the turbo size, 100%injectors are more than plenty for the power range of the turbo. Yes, we have made around 2khp with the oval race cast pistons.

 

[Grimes_County LBZ]

I’m surprised that no one has opined about the cast iron heads and 9 blade. ? Getting soft around here ?

Just out of curiosity, what's the concern?

 

[Grimes_County LBZ]

Honestly not any real world info on the cast iron heads in a street truck that I have even seen or heard of. Everyone I know that tried to get a set of them couldn't even get them. The 9blade turbine, sound and performance is awesome but reliability is yet to be proven good yet. For the question asked about what injector size for the turbo size, 100%injectors are more than plenty for the power range of the turbo. Yes, we have made around 2khp with the oval race cast pistons.

@MarkBroviak, thanks for the feedback! I really appreciate it!

 

[Grimes_County LBZ]

Fingers pistons have gone into the 2k range with no issue iirc.

100% overs on a single 64 is a good route. Leaves room to grow for compounds. Tbh, a 1500uS tune on a single 64 and 100% overs will be smokey. Add a compound and its going to make another 100hp on the same tune just from cleaning up the smoke

@Chevy1925, thanks for the feedback!

 

[1FastBrick]

Just out of curiosity, what's the concern?

The 9 blades don't last from any manufacture.... Also No one really has enough time on the Cast Iron Heads since they came out.

 

[Bdsankey]

Pistons - I think Mark, Brett and Nathan are the highest HP guys I know of personally with cast ovals and they've all been around that 2k whp level. In my personal opinion it doesn't get any better than cast ovals for a street engine, especially with Dynomite now offering an oval bowl specific nozzle. With that nozzle I've seen some great improvements in idle haze (not that they were bad) and they've seemingly now tuned like stock piston trucks.

Heads - Personally I think the iron heads are a waste of money. They don't do anything better for 99% of the market. If you want new castings the I would direct you to Fleece. The Fleece heads are insanely proven and are ~$400-$500 cheaper than PPE even after buying a high quality spring set from Manton/XDP or SoCal. You can get top tier pushrods as well and still have enough left over to buy a nice steak dinner.

Injectors/CP3 - Personally I would recommend something in the 100% injector area and a 10mm at minimum (ideally 12mm) so you have some room to grow. A 64mm VGT/S480 is a nearly unbeatable street/towing setup for the guy aiming to make 800-900whp area with phenomenal response. A 100% can also be turned down to run very well with just a small drop in/built trans.

Turbos - My shop will not install a 9 blade as the quality is far too inconsistent to the point where they fail prematurely AND they really don't do anything better than a 10 blade. A 10 blade tends to make more average HP/TQ across the graph when compared to a 9 blade, 9 blades only really make more HP up top IF the 10 blade turbine the builder uses gets into a "choke" condition and can't keep up with exhaust flow.

I personally am a large fan of JZ Mfg and Fleece for drop-in turbos.

 

[Grimes_County LBZ]

Pistons - I think Mark, Brett and Nathan are the highest HP guys I know of personally with cast ovals and they've all been around that 2k whp level. In my personal opinion it doesn't get any better than cast ovals for a street engine, especially with Dynomite now offering an oval bowl specific nozzle. With that nozzle I've seen some great improvements in idle haze (not that they were bad) and they've seemingly now tuned like stock piston trucks.

Heads - Personally I think the iron heads are a waste of money. They don't do anything better for 99% of the market. If you want new castings the I would direct you to Fleece. The Fleece heads are insanely proven and are ~$400-$500 cheaper than PPE even after buying a high quality spring set from Manton/XDP or SoCal. You can get top tier pushrods as well and still have enough left over to buy a nice steak dinner.

Injectors/CP3 - Personally I would recommend something in the 100% injector area and a 10mm at minimum (ideally 12mm) so you have some room to grow. A 64mm VGT/S480 is a nearly unbeatable street/towing setup for the guy aiming to make 800-900whp area with phenomenal response. A 100% can also be turned down to run very well with just a small drop in/built trans.

Turbos - My shop will not install a 9 blade as the quality is far too inconsistent to the point where they fail prematurely AND they really don't do anything better than a 10 blade. A 10 blade tends to make more average HP/TQ across the graph when compared to a 9 blade, 9 blades only really make more HP up top IF the 10 blade turbine the builder uses gets into a "choke" condition and can't keep up with exhaust flow.

I personally am a large fan of JZ Mfg and Fleece for drop-in turbos.

@Bdsankey, thank you for a very informative reply. All of that makes sense.

I currently have a Ryan's 61mm Pro-Stock (10 Blade) in the truck. Replaced it 2 years ago when the stock turbo died. So far, so good; no issues. I was unaware that the 9 blade had reliability issues. And, considering your reasoning, will stick with a 10 blade for the new drop-in. That makes sense.

The compound setup you described 64 VGT/S480 is exactly what I am considering long term, just can't realistically afford it at the moment. The engine build in and of itself is getting pricy! As for the Injectors/CP3, I figured I would need a stroker pump, thanks for the recommendation.

My justification for the heads is thermal expansion. I feel far more comfortable knowing that the heads and block are expanding/contracting at the same rate. No point in spending $20,000 + on an engine build, and still risk blown head gaskets. I understand that the stock heads are reliable, and some may say it's not worth the money, but IMO, the extra insurance is worth it. And, somebody has to get them, or real-world data will never be gathered on these... I am willing to help gather that information and provide feedback.

As I start to build this thing out, I will post pictures, and keep everyone updated. Again, I really appreciate the advice. It's reassuring to know that I'm on the right track!

 

[N2BRK]

The heads aren't proven and seem to be a solution in search of a problem. This comes at a premium price and substantial weight. Money is better spent on Fleece Freedom aluminum heads and some studs and springs etc.

9 blades are a current fad for little boys that want noise. They are not reliable and the most popular topics on most social media diesel groups is their early failure. There are the few guys that are a couple years and some miles on them, but it's rare. Most fail very early.

I'd get with some people that have a reputation and credentials in the business and will steer you toward a solid tried and proven build plan, since you aren't asking for something unusual or new goal. Brad is certainly one of them (above).

Again, I can't stress searching this site as much as possible. There's a TON of great information here and the s/n ratio is much lower than anywhere else.

 

[Bdsankey]

@Bdsankey, thank you for a very informative reply. All of that makes sense.

I currently have a Ryan's 61mm Pro-Stock (10 Blade) in the truck. Replaced it 2 years ago when the stock turbo died. So far, so good; no issues. I was unaware that the 9 blade had reliability issues. And, considering your reasoning, will stick with a 10 blade for the new drop-in. That makes sense.

The compound setup you described 64 VGT/S480 is exactly what I am considering long term, just can't realistically afford it at the moment. The engine build in and of itself is getting pricy! As for the Injectors/CP3, I figured I would need a stroker pump, thanks for the recommendation.

Completely understand. That's why I believe a 100% injector will be your best bet as it works with your current setup and your future goals.

My justification for the heads is thermal expansion. I feel far more comfortable knowing that the heads and block are expanding/contracting at the same rate. No point in spending $20,000 + on an engine build, and still risk blown head gaskets. I understand that the stock heads are reliable, and some may say it's not worth the money, but IMO, the extra insurance is worth it. And, somebody has to get them, or real-world data will never be gathered on these... I am willing to help gather that information and provide feedback.

As I start to build this thing out, I will post pictures, and keep everyone updated. Again, I really appreciate the advice. It's reassuring to know that I'm on the right track!

This is NOT why our HGs fail. Many trucks have gone 400-500k. They typically fail from OEM gaskets being crimped vs riveted. LMLs fail because the OEM HG (GM gold) is garbage to begin with. When my customers build an engine I try and push them all to ARP 625 studs. To date, I have not had a single issue with Mahle HGs, OEM reworked or new Fleece heads, and ARP625 studs up to the 1000-1200whp mark. Over that I like to add a stainless steel o-ring into the deck surface to gain more "crush" on the gasket.

The steel heads do not solve any issue we have for 99% of people. Guys have gone a million miles on OEM heads, if it was an expansion issue we wouldn't have seen this after one HG change. The PPE steel heads flow like OEM and come with an unknown spring pack it seems like. They add nose weight/pull your back muscles more than the aluminum versions, that's about it. So if you want more of a workout I guess they solve that issue haha.


Fleece heads have been used for years now on many builds including those in the 1500-2000whp issue without a single issue. They're dimensionally stable, are from a company that stands behind their products/is constantly innovating, and proven reliable as hell.

 

[Grimes_County LBZ]

Completely understand. That's why I believe a 100% injector will be your best bet as it works with your current setup and your future goals.


This is NOT why our HGs fail. Many trucks have gone 400-500k. They typically fail from OEM gaskets being crimped vs riveted. LMLs fail because the OEM HG (GM gold) is garbage to begin with. When my customers build an engine I try and push them all to ARP 625 studs. To date, I have not had a single issue with Mahle HGs, OEM reworked or new Fleece heads, and ARP625 studs up to the 1000-1200whp mark. Over that I like to add a stainless steel o-ring into the deck surface to gain more "crush" on the gasket.

The steel heads do not solve any issue we have for 99% of people. Guys have gone a million miles on OEM heads, if it was an expansion issue we wouldn't have seen this after one HG change. The PPE steel heads flow like OEM and come with an unknown spring pack it seems like. They add nose weight/pull your back muscles more than the aluminum versions, that's about it. So if you want more of a workout I guess they solve that issue haha.


Fleece heads have been used for years now on many builds including those in the 1500-2000whp issue without a single issue. They're dimensionally stable, are from a company that stands behind their products/is constantly innovating, and proven reliable as hell.

@Bdsankey, 10-4! I can't argue with the info on the heads or head gaskets, your points are well received. I appreciate your experience.

Target for the build is 850hp (after the compound turbo setup is installed). Given that I am not exceeding the 4-digit number, I don't think O-Rings are necessary. I absolutely agree with Mahle HGs, and ARP studs, but also desire ported heads to improve airflow, and enhance turbo efficiency. Does Fleece offer a ported version of their heads?

 

[Bdsankey]

@Bdsankey, 10-4! I can't argue with the info on the heads or head gaskets, your points are well received. I appreciate your experience.

Target for the build is 850hp (after the compound turbo setup is installed). Given that I am not exceeding the 4-digit number, I don't think O-Rings are necessary. I absolutely agree with Mahle HGs, and ARP studs, but also desire ported heads to improve airflow, and enhance turbo efficiency. Does Fleece offer a ported version of their heads?

They (Fleece) does not themselves. I do not know anyone who's offering a porting program for Fleece's heads yet as that requires a lot of "scrap" to cut heads apart and see how much variance there is in internal geometry.

I've yet to see a ported head hold up long term on a street truck, most seem to develop some form of crack after years of abuse. To be fair, these to date have all been ported OEM castings as the aftermarket Fleece castings are relatively new so time will tell.


At your HP, I personally would leave them "as cast" and send it with a good set of springs. If anything, do some small blending/polishing. I've made 1300hp+ on OEM LLY castings, my close friend has made over 1500hp on stock castings, many others have done that as well with relatively similar boost vs drive pressure. Is there a gain? Yes, is it worth it for your 800-850whp to sacrifice some reliability? In my opinion no.

For under 1000whp I would run simply ARP 625, Mahle HGs, and a quality machined head/deck surface. Proper deck/head surface finish is a huge part of keeping the engine sealed.

 

[malibu795]

@Bdsankey I've have shit luck with OEM GM black head bolts, I've lifted everything set ive had with a tow tune, the silvers head bolts have held..as long as I install them right ?.
Current truck hasn't ran long enough to lift them yet???‍

Naturally the OP is well passed OEM head bolt capacity for goals