Dyno Testing a stock 440..........

Dave-R · Post by **Dave-R** » Tue Dec 16, 14 12:24 pm

I would say your heads were the limiting factor Les so most of that big cam lift was wasted.

Compression does not have as big an impact on HP as you might think.

I think the only real difference between your engine and that one was slightly better heads.

Les Szabo · Post by **Les Szabo** » Tue Dec 16, 14 12:43 pm

Yes the cam was wasted to some extent Dave as 10.3:1 was not enough CR for it, should've been at least 12.5:1, and with that duration of 290@.50, cylinder pressure was not the best, and that is the key to it all. However, the cam did work well with those heads in the respect that they kept the valves open longer. I still do not think you will make 449hp from a 7.8:1 motor with that spec.

Blue · Post by **Blue** » Tue Dec 16, 14 12:46 pm

Having used a .509 cam in a low compression 440, I have to say the results were dissapointing. Doing little more than upping the compression to around 10.5 made a huge difference. No Hp figures for either, only the seat of the pantsometer.

Trigger_Andy · Post by **Trigger_Andy** » Tue Dec 16, 14 12:55 pm

Not that I know anything about this but would your figures be Rear wheel BHP Les and the Dino obviously at the Flywheel?

Les Szabo · Post by **Les Szabo** » Tue Dec 16, 14 1:01 pm

No Andy, Wallace Calc is Fly hp, rw hp was around 426......

RobTwin · Post by **RobTwin** » Tue Dec 16, 14 1:25 pm

Great post Dave, thanks

Shame they didn't compare the std 906 heads with a set of ported 906 heads tho, instead of a set of ported 516's, just to illustrate the difference the porting makes .

Aren't 906s sposed to be better than 516s? That's what I've read elsewhere. A 34hp gain is impressive enough but they may have got even more using 906s...

Trigger_Andy · Post by **Trigger_Andy** » Tue Dec 16, 14 1:28 pm

Told you I did not know anything.

Les Szabo wrote:No Andy, Wallace Calc is Fly hp, rw hp was around 426......

Dave-R · Post by **Dave-R** » Tue Dec 16, 14 1:30 pm

906s were the best stock head at that time (when the engines they were fitted to were first produced) but porting is porting and they all flow about the same when ported professionally. Except that you can only go so far with the 906 heads. Later heads had more material to work with so are easier to port better without welding and epoxy. Not sure about these 516 heads.

It all depends how radical they have been done.

Les Szabo · Post by **Les Szabo** » Tue Dec 16, 14 1:48 pm

RobTwin wrote:Great post Dave, thanks

Shame they didn't compare the std 906 heads with a set of ported 906 heads tho, instead of a set of ported 516's, just to illustrate the difference the porting makes .

Aren't 906s sposed to be better than 516s? That's what I've read elsewhere. A 34hp gain is impressive enough but they may have got even more using 906s...

I did have a chart in my favourites that showed that the 906 was NOT the best head when ported with the same MP porting templates, it was down nearly 20cfm over 516, as cast it was comparable to the others....google it.

Dave81 · Post by **Dave81** » Tue Dec 16, 14 1:57 pm

RobTwin wrote:Great post Dave, thanks

Shame they didn't compare the std 906 heads with a set of ported 906 heads tho, instead of a set of ported 516's, just to illustrate the difference the porting makes .

Aren't 906s sposed to be better than 516s? That's what I've read elsewhere. A 34hp gain is impressive enough but they may have got even more using 906s...

My understanding is that he used whatever he could get his hands on!

Would have been interesting to see for sure.
Thinking about it I'm sure I've seen another US thread elsewhere where they did exactly that.

It was based of headflow rather than bolted down power gains......The ole More in More out philosophy!

Dave81 · Post by **Dave81** » Tue Dec 16, 14 2:05 pm

This wasn't the one I remember (as I think it was SB based), but interesting stuff all the same......

Part 1
http://www.hotrod.com/how-to/engine/511 ... der-heads/

Part 2
http://www.hotrod.com/how-to/engine/511 ... -heads-ii/

Les Szabo · Post by **Les Szabo** » Tue Dec 16, 14 2:25 pm

Yes Dave its what cfm the heads are and how fast and where the flow is, whether they are 906/516, whatever, in this case it was overkill for that set up/cam.

Stock heads flow around 190>200cfm, at 261cfm flow those heads had well enough flow for that .495 lift cam and then some, but, its all about matching parts and the key to hp is cylinder pressure (how big the bang is) the cam will have a direct effect on that, lift/duration, overlap etc. in the filling cycle. Thats why big race cams need a lot static CR (12:1 say) to make good cylinder pressure and big hp. You ain't gonna make hp like that with 7.85:1 and a cam as big as that in my book.

Les Szabo · Post by **Les Szabo** » Tue Dec 16, 14 3:26 pm

To give you all an idea on this, a certain fellow member runs a 440 which is around 588hp, approx 100hp more than my 440 was. Part of that are the heads 45>50cfm more than my 906's = say around + 50hp, the other 50hp is from his static CR of around 12.6:1 with only a .590 cam that is less in duration etc than mine was = even more cylinder pressure = the other 50hp, when all that is combined in a matched set up thats the result, but you have to have the CP their for it make good power, without it you would be down around 50hp at say 10.3:1CR, so CP makes a big difference, even at the lower end of the performance ladder.

Dave-R · Post by **Dave-R** » Tue Dec 16, 14 3:37 pm

I would have thought peak HP at high rpm wouldn't be much different.
Down a bit but not a huge amount. The main difference being a lack of power at lower rpms.

Or maybe I am thinking of peak torque?

At least that is what I was told as a young'un.

I have a huge lack of hands on experience with building different engine combos though. And it shows.

Les Szabo · Post by **Les Szabo** » Tue Dec 16, 14 4:05 pm

Yes were talking hp only not torque. A mild build is a different kettle of fish, torque is the main consideration, however, I wouldn't call that example as a mild motor apart from the 7.8CR which is where I cannot see that the amount of CP with that large cam would pull it to 449hp....but anyway its a good discussion point, and I guess Dyno's don't lie eh