I'd love to see a dyno run with these on an otherwise stock 400. Being able to actually run some timing without turning the engine into a grenade would be nice.
Me too. I'd like to see a closed chamber 2V head with raised exhaust ports on a 400. Something that would raise the compression ratio by a point and a half. Watching this article, I do not understand WHY somebody would go to all the trouble to cast an aluminum Cleveland head and not raise the exhaust ports. Keey the port design so as to be compatible with stock headers, but put it around 3/4" higher. The acknowledged shortcoming with Clevelands is their crappy exhaust ports. But why make some new heads but not solve the exhaust port problem.
@@bobkonradi1027 raising the ports on a low buck head makes no sense as it would eliminate using them on a stock shock tower car like a mustang or cougar without expensive headers. Using those headers eliminate any advantage of the raised ports as you simply exchange the port flow issue to a header flow issue due to the shape transition required.
See flowtest on the Promax 4V/3V heads in the replies section below on "Stock flow #'s on LS3 heads"? They're noticeably less than the 2V's in this test, OTB.
Looking to rebuild my 351 Cleveland. Nothing extreme just something a bit more torque than stock. it is in a semi-daily driver F100. The previous owner put 351M heads on the Cleveland block. My question is would these heads be to hot for my application?
From the facts presented in this Promaxx video, I think these heads would be a good choice for your application. The biggest advantage would be the modern combustion chamber design with smaller volume. The compression increase would provide a very noticeable increase in torque and horsepower while still using pump gasoline. The 351M heads would require a lot of work and expense to flow as well as these alloy heads. The reduced weight of aluminum has obvious benefits as well. The exhaust ports being in the stock location will allow more choices for the exhaust system. Too hot for your application ? No way 🏁.
So what you are saying is the CHI 185 and 208 head will make more power, my guess it at least 70 on the TQ and 50 on the HP. Why would you run an outdated 2V head in aluminum.
It depends on your application. And budget. The 2V heads are comapable with genuine parts. Intakes, exhaust manifolds etc. The 185 3V are better,, a friend has 500 real wheel HP on a 377 Clevo. But then you need the matching intake. I was very surprised by the driveability of them on the 377 BUT that has a 3.7 diff and a 5 speed Tremec. On my 400 Galaxie cruiser with 3.00 they would be useless,, the 2V version a lot better. Though it will stay with 2V 302 heads as they do the job ok. Those CHI 2V heads will sharpen up any mild Clevo. As will most better aftermarket heads. And they are a third of the weight.
@@ldnwholesale8552 So then you are telling me that a 2v head with a larger port and less air flow , will have better drivability then the 185 CHI head with more flow thru a smaller port.
LS engine is a copy of a Ford engine design so who cares. Notice how the new GM 1000hp crate engine has FORD designed even spaced intake runners for the heads and intake 🤔
@@mikeeagle2653 wrong about what? How about you be more specific... The architecture and design of the LS block is from a Ford FE and the bore spacing is only .02" difference than a SBF. I personally put my stepdads 5.7 LS heads on a Cleveland block just to prove this point - just for fun though and to piss him off chevy made a Ford engine. And yup he new gm 1000hp crate engine has equal length FORD intake runners on heads and intake. ua-cam.com/video/wgSoHlSU3WI/v-deo.html
I saw the CNC ported version of this head at PRI and am seriously considering it for my next engine build.
Absolutely awesome explanation of what defines theses difference's
Great content! The quality has improved since the beginning. I just subscribed. Keep up the great work.
Excellent presentation
So great when people have charts on a pause-able video and feel a need to go line by line by line and tell us what we can plainly see.
I think you have to Flow that Promaxx head, get all lift figures...i reckon those figures are for a CNC ported head...
I'd love to see a dyno run with these on an otherwise stock 400. Being able to actually run some timing without turning the engine into a grenade would be nice.
Me too. I'd like to see a closed chamber 2V head with raised exhaust ports on a 400. Something that would raise the compression ratio by a point and a half. Watching this article, I do not understand WHY somebody would go to all the trouble to cast an aluminum Cleveland head and not raise the exhaust ports. Keey the port design so as to be compatible with stock headers, but put it around 3/4" higher. The acknowledged shortcoming with Clevelands is their crappy exhaust ports. But why make some new heads but not solve the exhaust port problem.
Will they fit a 400? I have one.
@@steveharper9964 yes they will.
@@bobkonradi1027 raising the ports on a low buck head makes no sense as it would eliminate using them on a stock shock tower car like a mustang or cougar without expensive headers. Using those headers eliminate any advantage of the raised ports as you simply exchange the port flow issue to a header flow issue due to the shape transition required.
@@Ares-jx4ep if they are raised and your using them on a 302 just order the headers for a Cleveland and should be really close
When will they be available again? ?
Sweet
And more content!
How about testing the 4V heads?
Check out Promax 4V/3V flow test in the replies section... " Stock flow figures of LS3 heads" by Mike Eagle.
See flowtest on the Promax 4V/3V heads in the replies section below on "Stock flow #'s on LS3 heads"?
They're noticeably less than the 2V's in this test, OTB.
Is this Terry ?
When say, "high lift" and you refer to TFS or AFR cylinder head being the better choice...could you elaborate?
I have a Set of TFS Street Heat Cast Iron Small Block Heads I Need Ported . Were Can I Get them Ported . Thanks
what was th ebore plate used vs ProMaxx? they might have used a 4.125 plate?
Have you guys tested the 4V Cleveland heads Promaxx offers?
What is the calculated cross section and port volume ?
Looking to rebuild my 351 Cleveland. Nothing extreme just something a bit more torque than stock. it is in a semi-daily driver F100. The previous owner put 351M heads on the Cleveland block. My question is would these heads be to hot for my application?
Should be fine
From the facts presented in this Promaxx video, I think these heads would be a good choice for your application. The biggest advantage would be the modern combustion chamber design with smaller volume. The compression increase would provide a very noticeable increase in torque and horsepower while still using pump gasoline.
The 351M heads would require a lot of work and expense to flow as well as these alloy heads. The reduced weight of aluminum has obvious benefits as well. The exhaust ports being in the stock location will allow more choices for the exhaust system.
Too hot for your application ? No way 🏁.
The Chevy guys are gonna take one look at those things and ask for at least 4 bulbs!!! And they can't hold a light to true Yates heads!!
Are those 225cc number the un-ported numbers
Valve stem size
So what you are saying is the CHI 185 and 208 head will make more power, my guess it at least 70 on the TQ and 50 on the HP. Why would you run an outdated 2V head in aluminum.
It depends on your application. And budget. The 2V heads are comapable with genuine parts. Intakes, exhaust manifolds etc.
The 185 3V are better,, a friend has 500 real wheel HP on a 377 Clevo. But then you need the matching intake. I was very surprised by the driveability of them on the 377 BUT that has a 3.7 diff and a 5 speed Tremec.
On my 400 Galaxie cruiser with 3.00 they would be useless,, the 2V version a lot better. Though it will stay with 2V 302 heads as they do the job ok. Those CHI 2V heads will sharpen up any mild Clevo. As will most better aftermarket heads. And they are a third of the weight.
@@ldnwholesale8552 So then you are telling me that a 2v head with a larger port and less air flow , will have better drivability then the 185 CHI head with more flow thru a smaller port.
Where are the Pro Max head's made and is the quality there ? Any information that You can provide will be appreciated Thank You . 🇺🇲🇵🇷🦊👍
The price structure of the Promaxx heads seem to say they were made in China.
Where can you get those at?
Where is the casting done ?
Good question
Stock flow numbers for LS3 heads. Lmao 😂
LS engine is a copy of a Ford engine design so who cares. Notice how the new GM 1000hp crate engine has FORD designed even spaced intake runners for the heads and intake 🤔
@@nova467spanker wrong
@@mikeeagle2653 wrong about what? How about you be more specific... The architecture and design of the LS block is from a Ford FE and the bore spacing is only .02" difference than a SBF. I personally put my stepdads 5.7 LS heads on a Cleveland block just to prove this point - just for fun though and to piss him off chevy made a Ford engine.
And yup he new gm 1000hp crate engine has equal length FORD intake runners on heads and intake.
ua-cam.com/video/wgSoHlSU3WI/v-deo.html
LS has been beaten to death. They're not interesting or cool anymore. Just an engine that is plentiful in junkyards.
@@Francis_Castiglione lmao 😂 that’s common line from haters. Still winning more races then everything else for less money
Chevy are cheaper to make horse power