Cylinder head dyno shoot out

[Dartswinger70]

You edited your message,
X heads are valuable for reasons other than making power.

I do that alot. My original thought wasn't worth the interaction. I think I can deduce what's going on here in regard to "stock heads" and decided to bow out.

However if I were to speculate, I'd guess the interest lies in random sets of modded Speedmaster heads and a set of Edelbrocks to mix it up, am I close?

 

[NC Engine Builder]

Yeah, I understand the premise behind wanting a baseline, but like has allready been pointed out, there really is no baseline for a 400 plus inch build with a factory casting head.

 

[DionR]

Yeah, I understand the premise behind wanting a baseline, but like has allready been pointed out, there really is no baseline for a 400 plus inch build with a factory casting head.

PowerNation did a 360 stroker build with stock heads, RPM AG and the stock cam and made 339 HP and 498 torque. Is that enough of a baseline?

My opinion is that the heads weren't the limiting factor, I think it was the broomstick cam is what kept the HP down. But almost 500 ft/lbs??? Either way, I guess probably not the baseline needed for a cylinder head shootout.

 

[PRH]

Keep in mind, it doesn’t really matter what order the heads are tested in.

If there were enough interest in oe head testing, after the first round has been completed……… maybe some people could make donations to pay for that to happen(I’m just throwing it out there).

Dyno testing is expensive……… saying “just throw on some stock heads” represents several hundreds of dollars worth of time and $$$……… plus the heads.

 

[Demonx2]

Yeah, I understand the premise behind wanting a baseline, but like has allready been pointed out, there really is no baseline for a 400 plus inch build with a factory casting head.

Let's be honest here....the REAL reason for wanting to baseline some stock OEM heads on the stroker is so you can justify a bunch more $$'s to the boss and say "See, look how much better this things gonna be if I just spend a little more and get those (fill in the blank) heads. I know I already spent a fortune on it but this is just gonna be great!"

 

[PRH]

Actually, to refurbish, repair, modify factory heads to be somewhat comparable to even ootb Ede type heads…….. at my shop anyway……… will typically cost more than the SM heads.
If you’re starting with old used up castings, which most are by now, the days of them being the “cheap” way out are pretty much over.

 

[Dartswinger70]

Yeah a stock baseline is moot I see that now. actually Nicks garage ran a stock 340 (or it looked stock) and I think he got 335 or 340 horse out of a pull. So I guess I'm saying it's already documented about what you could get in a stock configuration. So that leads to the question where would the starting point be? what configuration or setup?

 

[PRH]

That’s for NC EB to determine.

I made my suggestions earlier in the thread.

 

[rumblefish360]

If someone had a suitable set of oe la heads that are truly “ready to run” for this application, that they’d offer up for the cause, that might make it worthwhile.
But to have to build a set of heads for the test, then I think the time and $$$ would be better utilized on something else.

I have a ‘75-ish 1.88/1/60-360 heads ready to rock and roll. Springs are a different issue though.

 

[rumblefish360]

PowerNation did a 360 stroker build with stock heads, RPM AG and the stock cam and made 339 HP and 498 torque. Is that enough of a baseline?

My opinion is that the heads weren't the limiting factor, I think it was the broomstick cam is what kept the HP down. But almost 500 ft/lbs??? Either way, I guess probably not the baseline needed for a cylinder head shootout.

Wasn’t that a Magnum 5.9 stroked with a 4 inch arm later?
I think that’s a great base line to spring from since the LA head is a half step behind the Magnum head in terms of flow cfm.

I honestly think it is a bit unrealistic- not that it hasn’t been done - that a set of OEM heads would permanently grace the up of a stroker 400+ engine. Not saying, again, that it hasn’t been done and someone is doing it now.


I’ll also say I don’t think it’s a bad idea. I myself would disappointed if that’s as far as it goes for me. Bottom line when that’s done, I’d guess it would be a money issue for some.
And that’s OK.

 

[DionR]

Wasn’t that a Magnum 5.9 stroked with a 4 inch arm later?

They dyno'ed the 5.9 and got 305/414 and then added the stroker kit and finished with the 339/498.

 

[273]

They dyno'ed the 5.9 and got 305/414 and then added the stroker kit and finished with the 339/498.

Don't forget the almost 2 points of added CR over stock with the stroker kit.

 

[NC Engine Builder]

They dyno'ed the 5.9 and got 305/414 and then added the stroker kit and finished with the 339/498.

Basically shows about what I'd expect. Extra torque from the added cubes, with nowhere near enough airflow to make any power

 

[TT5.9mag]

They dyno'ed the 5.9 and got 305/414 and then added the stroker kit and finished with the 339/498.

My stock stroke 5.9 magnum 300 crate with a 212/218 comp cam and an rpm air gap made 26 more than their stroker. No where near 498lb/ft though. Mine made 423lb/ft.

 

[mbaird]

They got 498 hp out of factory heads and cam ? Hmmm…. Sounds suspicious.

 

[273]

They got 498 hp out of factory heads and cam ? Hmmm…. Sounds suspicious.

498 Torque from a 410

 

[mbaird]

498 Torque from a 410

Oh .. 498 was the torque . Still sounds a bit high using untouched heads and factory spec cam . Of course they did run headers and air gap intake .
This is why we need our own member doing these tests . Keep things honest !

 

[DionR]

My stock stroke 5.9 magnum 300 crate with a 212/218 comp cam and an rpm air gap made 26 more than their stroker. No where near 498lb/ft though. Mine made 423lb/ft.
View attachment 1716338909

Goes to show how small the factory cam is.

 

[rumblefish360]

They dyno'ed the 5.9 and got 305/414 and then added the stroker kit and finished with the 339/498.

Yep! That’s the episode! Lived the two episodes. That was cool IMO.

My stock stroke 5.9 magnum 300 crate with a 212/218 comp cam and an rpm air gap made 26 more than their stroker. No where near 498lb/ft though. Mine made 423lb/ft.
View attachment 1716338909

What size header?!?!
And exhaust?

 

[TT5.9mag]

Yep! That’s the episode! Lived the two episodes. That was cool IMO.


What size header?!?!
And exhaust?

1-3/4 dyno header. Don’t remember if it had an extension on it or not. Probably not.
Edited to add;
Just went back and checked the engine masters episode my engine was on, S6 E23 and it did have an extension on the header. Looks like about 18”.

 

[Ironmike]

 

[273]

1-3/4 dyno header. Don’t remember if it had an extension on it or not. Probably not.

Wasn't the engine from Richard Holdener and Engine Masters ?

 

[NC Engine Builder]

Well, everyone loves pictures, and I figured I'd share the build as I go. So here is our garden variety '71 360 block, stripped, thermally cleaned and shot blasted. Its actually a "496" casting which some claim to be thicker. Also, if you pay a shop to clean your block, and it doesn't look similar to this, I dont consider it clean!

 

[TT5.9mag]

Wasn't the engine from Richard Holdener and Engine Masters ?

Yes. Holdener did a bunch of testing with it and engine masters made one episode with it.

 

[NC Engine Builder]

Here is another airflow limited dyno test of a oval track 360 I did 7 or 8 years ago. It's a .010 over zero deck stock stroke 360, with a .420! Lift hydraulic flat tappet cam (class rules) a set of EQ magnums, no porting allowed, but bunch of time spent on the valve job, a shitty edelbrock performer 318/360 (class rule again) and a 500 holley two barrel carburetor. 1 5/8 garbage headers.