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!

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.

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

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

Thats some pretty good power and torque!

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.

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!

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.

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

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!