[DeTomaso] Dyno Testing Update - unported iron 4V head testing

[Daniel C Jones]

Let me reply to several posts at once.  I've also included questions
and answers from another list/forum.

> So.... what I got out of this initially is that the stock 4V closed
> heads Rock! Of course that depends on the intake and exhaust.

Yes.  I'm wondering if the ported 4V's will match or beat the CHI's
on HP.  My guess is they will still be down some on peak torque due
to the larger cross-sectional area but match them on HP.

> So if the stock exhaust manifolds aren't so great, and the mufflers
> either, what is the best breathing combination to put on, and still
> clear the a-arms?

The GTS headers did pretty well (similar peak power but down on torque)
in previous testing but could likely use a better collector.  Mufflers
need to straight through designs.  Magnafolw has a 3" single inlet,
dual 2.5" outlet muffler I'm interested in.  Also, dual round mufflers
(per side) might work well.

> I added the note to the others on the website.
> http://poca.com/index.php/tech/58-dyno

Thanks.  Eventually, I'll put together some articles for the newsletter
with tables and graphs.

> Regarding the Funnelweb intake test: did you use the intake port stuffers
> with the Funnelweb intake???

Without. I don't have any stuffers and didn't want to permanently modify
the heads with them.  I think the Funnelweb would do better with the
stuffers.  When cross-sectional area changes from small to large, you
get a pressure loss and slow down in flow which is not good for power.
I suppose we could temporarily stuff the port if someone came up with
the stuffers.

> Are you planning on testing the stock GTS Ansa mufflers

I only have the non-GTS mufflers here now (off of one of my '74 L Panteras).
We tested the GTS mufflers previously on the 408C and also lost 50 HP.
The % loss on that 500 HP engine was lower but the GTS mufflers are still
corks.

> and a gutted Ansa to see if gutting them like the Space City boys or Mike
> Drew or any one of a number of others brings any real benefit?

Mike said he was going to gut a set and send my way.  Mike, what's the
status on that?

> Would such a modification require rejetting the carb to make more power,
> since you are now flowing more air, or will you make more power as-is?

Potentially yes.  Anything that changes air flow, can affect jetting
requirements.

> Did my 180's not fit on the dyno? I know there was talk they would not fit.

We haven't trial fit them yet.  I wanted to wait until we had the 4V
heads on the engine.

> I think I let you use my Boss iron heads that have tapped rocker studs.

Yes.  Come to think of it, we may be using them for the unported heads
and have the bolt-downs on the ported heads.  I'll have to check.

> When will the Weber's go on?

The Webers go on when we test the ported 4V heads.

> I'm happy with those results.  My intake seems to work just fine
> considering it's a stock appearing Low-Rise design.

Yes.  The CHI single plane is a very good piece, perhaps the best
single plane race intake, but it is very tall with a large plenum
and does not fit under most street car hoods.  The fact that your
low-rise dual plane is so close on peak power is impressive.
Furthermore, the extra hood clearance allows for a better air
cleaner set up, prefereably ducting cold air in.  I'm looking forward
to testing your intake on the A3 and 4V heads.

> Both you Guy's keep up the great & imformative work .

Thanks.  Are you still planning on sending over a pair of the
cylinder heads you are developing?

> Are you still using the Reed cam with 228/232 on a 107 LDA?

Yes.  Short block specs below.

> BTW is there any way to test the CHI intake on the Iron heads?

Yes.  See below.

> I'm going to test the CHI piece on some of the 4V heads but to do that
> I need to pull out the dowel pin that's on the intake face.  It interferes
> with the CHI piece.

Do you want to test the CHI single plane on both the unported or just
the ported 4V's?  I guess it's not much more work to run it on both.

> I seem to think that it will be the best intake but time will tell.

It will be interesting.  To my eye, the CHI looks like the best race
intake design but, on a 4V head, it will suffer a bit from the volume
expansion at the 4V cylinder head.  I think that's what hurt the
Funnelweb.  I bet the Funnelweb would do better with the matching
intake stuffers.  In subsonic flow, when area changes from large to
small (like putting a 4V intake on a 2V port) there is time for the
flow to adjust gradually and flow speed picks up.  However, when area
charges abruptly from small to large, there's a flow speed reduction.
I guess we should test small port intake on large port head and vice
versa.

> Good stuff, Dan. I love that the old "peaky" iron C heads dusted the PCs.
> I assume at some point, you and/or Dave may post the actual graphs, for
> those who want to see what lies below the peaks?

Yes.  I'm going to copy all the results into an Excel spreadsheet
so each test can be plotted against any other.  I'll do the same for
the flow bench results too.

> Can't sing your virtues loud enough for taking this big task on.
> When you get ready to move some of the junk I sent you out of your way,
> just holler and I will get you some more funds to ship 'em back to me.

Will do.  I'd like to hang onto the CHI single plane to use on
the ported 4V heads.

> can you refresh us on what the short block consisted of....It's been awhile.

 Ford 351C block, 0.030" over (4.03" bore), 2 bolt mains, block did not
 require a re-bore as it had low miles since last being bored and was in
 good shape (no ridge), block was decked to clean up gasket surface
 Pioneer brass freeze plug set
 TRW L2379F forged flat top pistons with dual valve reliefs
 Ford 351C forged steel connecting rods (5.78")
 Ford 351C nodular iron crankshaft (3.5" stroke)
 Powerbond SFI balancer
 Ford Motorsport double roller timing chain (French Renold chain)
 Melling M84AHV mechanical high volume oil pump
 Ford Motorsport M-6005-A351 heavy duty chrome moly oil pump driveshaft
 Ford 351C passenger car front sump 5 quart oil pan
 Weiand 8209 aluminum 351C water pump
 MSD 8480 distributor (mechanical advance, large cap)
 Crane steel distributor gear (p/n 52971-1 for 351C with .531" shaft dia.)
 Cometic head gaskets (p/n C5871-040 for a 4.1" bore 351C/351M/400)
 FRPP M-6500-S58 "Early Block Hydraulic Roller Lifter Set". These are
 Crane p/n 36532-16 link bar retrofit roller lifters but were a little
 cheaper under the Ford Racing part number.
 Trend custom length push rods (for the taller roller lifters)
 Hastings moly rings (351C stock replacement)
 Clevite rod and main bearings (Std/Std)
 Crank treated to a light polishing
 Clearances are .0025" on rods and .0027" mains
 Fuel pump block off plate (dyno providing the fuel flow)

The camshaft is a Reed Cams steel core hydraulic roller, specifically part
number 535-TM280HR-284HR-107A.  I tried to pick the cam specs as a good all
around street cam that would work with all the heads being tested and have
a HP peak near 6000 RPM (6500 RPM shift point).  Specs are:

 228/232 degrees @ 0.050" lift (280/284 @ 0.006"), 0.588"/0.588" lift,
 107 LSA, 68 degrees overlap, installed in the engine on a 104 intake
 centerline.

Dan Jones