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Author Topic:   Our Dyno Experience - port plates
F551
Gearhead

Posts: 124
From: Manitoba, Canada
Registered: Nov 2000

posted 01-30-2001 09:59 PM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
Dyno time is money well spent!

651 ft/lb @ 4250 rpm
645 hp @ 6250

This is a 500cid cast crank /cast head (C8) combination. Used MPG portplates with a 1 7/8" header.

We didn't bother making a pull without the plates.
- the motor did better than we expected
- when the heads were flowed the bottom of the port was filled to get best flow
- we ran out of time as my brothers motor had to go on first thing in the morning.

Possibly the problems people have with the plates is rpm related? Our power was fairly down low.

Have people had poor results with just the 351C or the 385 series as well?

Now we just have to find the three tenths that are missing!

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

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kid vishus
Gearhead

Posts: 1994
From: huh?? what? who? ME!?!?!?!
Registered: Oct 2000

posted 01-30-2001 10:07 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
WOW, that's impressive!! Not so much the HP figures, but the torque!!

All I know about the port plates, is that on my C heads, with the way I had ported them, the plates actually hurt flow on the bench over .200 lift, and below that, they were only 1-2 cfm better.

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SteveLaRiviere
Administrator

Posts: 21832
From: Saco, Maine USA
Registered: May 99

posted 01-31-2001 11:20 AM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
Those are awesome numbers!

As for port plates, I can't help but wonder why MPG doesn't provide before/after dyno results or flow numbers. You would think they'd want you to know what the gains are.

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'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L Disposable Commuter

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tomslo
Gearhead

Posts: 200
From: Jefferson City, MO
Registered: Aug 2000

posted 01-31-2001 11:37 AM     Click Here to See the Profile for tomslo   Click Here to Email tomslo     Edit/Delete Message   Reply w/Quote
I was looking through a stack of old paper and whatnot last night and found some MPG port plate literature.
For the Cleveland 4v head, they show stock as being 94.0 cfm. Holstrom plates register a 94.3 cfm, MPG plates came in at 97.5 cfm, and the MPG Stinger plates flowed 101 cfm.
This was at .525 lift and 10" of water.
That was the only point of comparison at all, no other lifts, not even the standard flow conditions, and certainly no dyno numbers.

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Rustang1
Journeyman

Posts: 81
From:
Registered: Nov 2000

posted 01-31-2001 12:17 PM     Click Here to See the Profile for Rustang1   Click Here to Email Rustang1     Edit/Delete Message   Reply w/Quote
I'm curious as to how the headers used on the dyno test interfaced with the exhaust port? Are the tubes fairly straight where they exit out of the head, or do they turn down sharply like they would need to for shock towers? I have this theory that these plates, if they do work at all, would only show gains if the header tube doesn't turn down sharply as it exits the head. By the way, what's the formula for converting from 10" of water to 28"?

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1968 Mustang,Clevor,C4
1969 Torino 351C 4spd
1978 F150 460 C6
1978 F150 351W C6

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Ryan Wilke
Gearhead

Posts: 607
From: Stanton, Michigan
Registered: Oct 2000

posted 01-31-2001 05:12 PM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
Rustang1,
Your 'how to' question, "...converting from 10" of water to 28"" confuses me. They are values in the same units... Or,are you wanting the formula to convert from inches of water (in/H20) to inches of mercury (in/Hg), pounds per sqare inch (PSI) or to atmospheres (atmos)?

If so, then use the following:
in/H20 into in/Hg >>> multiply by 0.07355
in/H20 into PSI >>> multiply by 0.03613
in/H20 into atmos >>> multiply by 0.002458

Hope that helps!!!
Ryan

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F551
Gearhead

Posts: 124
From: Manitoba, Canada
Registered: Nov 2000

posted 01-31-2001 06:49 PM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
Rustang: We weren't able to use our headers as the collectors were to close and hit the dyno frame. The dyno operator was able to find a set same diameter 1 7/8" with 3 1/2" collector. Primary tubes were about 3" longer. Possibly they were for a Torino? The guy that had them bought them for a 390 - oh well.

The turndown at the flange was similair to our headers - turning down sharply to clear shock towers. I held a port plate to the header flange and it doesn't obstruct the tube as much as one would think.

MPG website just refers to a 25HP gain for DOVE style heads - and talks about port plates preventing reversion.

The 10" of water versus 28" water refers to the test pressure (in inches of water column)
that the flow test was performed at. There must be a way to compare these values - I believe 28" is a much more common value.
So I think a flow at 10" is lower numericaly than a flow at 28" for the same port.

Good info at Superflow.com

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

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TomP
Gearhead

Posts: 3609
From: Delta BC Canada
Registered: Dec 99

posted 01-31-2001 07:07 PM     Click Here to See the Profile for TomP   Click Here to Email TomP     Edit/Delete Message   Reply w/Quote
that sounds like a fair comparison ... sometimes dyno headers would only fit a dragster and the port plates might show a gain not possible on most cars.

Thats some pretty good power and torque!

Of course flow is all relative, and there is such a thing as too much flow.... or else the best heads would operate like an old step-to-open wastebasket... one really huge valve!

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kid vishus
Gearhead

Posts: 1994
From: huh?? what? who? ME!?!?!?!
Registered: Oct 2000

posted 01-31-2001 07:52 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
Were you using the flat plates , or the ones that have a more rounded floor? Or do they even make them for the 385 series? My flow tests were with the flat plates.
I had a wise man tell me once, that you can make up for a bad exhaust port with the camshaft, but a bad intake port is a bad intake port.

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F551
Gearhead

Posts: 124
From: Manitoba, Canada
Registered: Nov 2000

posted 01-31-2001 08:17 PM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
We were lucky, dyno operator really came thru for us with finding the headers. We asked him to see if we could buy them for next time. How do you post a picture, I took a couple of shots on the dyno - maybe someone might recognize the application.

The plates are cast Bronze and have a rounded tongue which fits the bottom of the port, took minimal fitting with a file. No plates on the intake, just matched the head/manifold.

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

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70coupe
Gearhead

Posts: 152
From: Toronto,Ontario,Canada
Registered: Aug 2000

posted 01-31-2001 09:02 PM     Click Here to See the Profile for 70coupe     Edit/Delete Message   Reply w/Quote
I'm curious about the port plates as well. The guy doing machine work on my 351c said he has a set of plates and will sell them to me for $70 cdn (cheap). So I bought them. This sounds like a good project for Mustang Monthly or Fast Fords! A worth while project for a change.

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Moneymaker
Administrator

Posts: 11493
From: Lyons, IL, USA
Registered: May 99

posted 01-31-2001 09:17 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
I would have still liked to have seen a pull without the plates.

------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link

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F551
Gearhead

Posts: 124
From: Manitoba, Canada
Registered: Nov 2000

posted 01-31-2001 10:01 PM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
Alex - me too!

But we had an issue with the carb, ended up milling the body as the A/F ratio was goofy and we had to get the other motor on dyno.
So ran out of time.

Most of the negative stuff I've read on plates has been Cleavland related, but we're pretty happy! The fellow that ran the dyno ported the heads/manifold - he was pretty confident the plates wouldn't hurt. Was our idea to buy them.

What kind of RPM were people looking for that they wouldn't work?

Also we ran a fairly small cam 256I/266E @ .050 and .589I/.615E. He found valve float at about 6600rpm so we are changing the cam
as we go thru the eyes at about 6900rpm. Springs checked OK - new last year.Don't know specifics on new cam - only is 10 degrees more and a Crane. Converter is in for insp/rebuild - they say they will tighten it up for us.

So much for the baseline!

10.4 - here we come!

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

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jkilroy
Gearhead

Posts: 1289
From: Austin, TX
Registered: Dec 99

posted 02-01-2001 08:13 AM     Click Here to See the Profile for jkilroy   Click Here to Email jkilroy     Edit/Delete Message   Reply w/Quote
Have you ever tried 2" headers on that motor? With all that torque I think it would be worth a try, you could probably pick up a few HP. Are your heads D0VE castings? How about the rest of your short block. I have a crank and a couple of blocks, I might just replicate your setup cause you are sure getting the power.

------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"

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Rustang1
Journeyman

Posts: 81
From:
Registered: Nov 2000

posted 02-01-2001 10:01 AM     Click Here to See the Profile for Rustang1   Click Here to Email Rustang1     Edit/Delete Message   Reply w/Quote
Ryan,
I guess what I meant to ask was what factor to use for converting flow numbers from 10" water to 28" of water.

------------------
1968 Mustang,Clevor,C4
1969 Torino 351C 4spd
1978 F150 460 C6
1978 F150 351W C6

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jkilroy
Gearhead

Posts: 1289
From: Austin, TX
Registered: Dec 99

posted 02-01-2001 01:37 PM     Click Here to See the Profile for jkilroy   Click Here to Email jkilroy     Edit/Delete Message   Reply w/Quote
I will try to dig up that conversion for you.

Until then I would like to say that the 10" number is a much more realistic figure to use. It is a shame that companies use the 28" figure as some kind of standard. I don't know about you but I don't think my 390 pulls 28" at any time, much less with the throttle wide open.

------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"

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Ryan Wilke
Gearhead

Posts: 607
From: Stanton, Michigan
Registered: Oct 2000

posted 02-01-2001 04:26 PM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
Jay,
Aren't most automotive vacuum gauges divided into units of inches of water; using a scale of 0 to 27.67"?

Don't most near-stock, in-tune, good-running, gasoline-powered autos operate at about 20"H20 vac at idle and that the vacuum 'strength' would drop to 9" or 10"H20 at initial WOT?

I would agree it is smart to compare data only when the conditions are similar; and that 10" isn't in the same ballpark with 28".
In fact, I'm not so sure an auto would even run at 28"H20 vacuum because it wouldn't contain enough fuel in the stream to support combustion...considering that no vacuum is 0" and a perfect vacuum is 27.67"H20 which contains no gasous air nor atomized fuel!

Provided: 29.929"Hg = 406.8"H20 = 1 atmos = 14.7 PSI

Ryan

[This message has been edited by Ryan Wilke (edited 02-01-2001).]

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F551
Gearhead

Posts: 124
From: Manitoba, Canada
Registered: Nov 2000

posted 02-02-2001 11:18 AM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
Jay - it's a good combo for a bracket motor, lots of comprimise for street.

2" header - We are very limited for headers, think there are two sets available commercially. Headers up here are likely $6 - 700, not a lot of spares laying around.The 1 7/8" which cross underneath and a 2" which allows PS. It is an extremely tight fit - we did not cut the shock towers. Was in the plans to make motor plates next year and build a set of headers - probably 2" - but now after the dyno - what we have doesn't look so bad. Our head guy figures the expense and work to fab headers isn't worth it for the heads we have.

Short Block - 429/460 block filled to the water pump holes - normal blueprinting.

Stock crank is off set ground for 500 cid with a .030" over piston. We inspect/mag the crank every year so far no problem. Know of a guy with Motorsport heads/cast crank, motor makes 850 HP - Crank good for two seasons. So we figure were safe.

Use a Rattler damper and a TCI flex plate.

Rods are Eagle 3D 6.800" BBC, with ARP L19 bolts. Bolts are an issue with this rod. After first year caps had walked. ARP said to use the L19 bolt and tighten by stretch.

Pistons are Arias with the lighter pins.
Think compresssion is about 12.5.

Heads - C8 castings with 2.190" Intake and 1.76" Exhaust. Use SpeedPro 1.73 roller rockers (they look like Cranes). Heads/intake ported, I don't have the numbers - think it was about 200 on exhaust and 300 Intake.

Cam was Comp 294-B-8 grind, found it floated above 6500rpm so a Crane is on order with about the same lift but another 10 degrees duration - get us away from the float.
Hopefully we don't have to cut the pistons!

Victor intake with 800 Holley on top of two 1" spacers.

MSD 7AL with a homemade crank trigger and MSD timing retard box.

My brothers new 383W made 653 HP and 550 ft/lb, much greater investment and higher rpm than the BBF. Although he has a lot of potential left in the heads and cam and our heads are pretty much maxed.

Kind of long winded - but you asked!

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

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jkilroy
Gearhead

Posts: 1289
From: Austin, TX
Registered: Dec 99

posted 02-03-2001 11:25 PM     Click Here to See the Profile for jkilroy   Click Here to Email jkilroy     Edit/Delete Message   Reply w/Quote
Thanks, thats just the kind of info that I was looking for.

------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"

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