Anyone have flow data for MR heads?

[chuckbrandt]

I was just playing with desktop dyno 2000 and looking at my planned 427 SO. I was disappointed to see it only having 385HP predicted. I was hoping for 400 or more. Desktop dyno allows the input of head flow data so I was hoping I could find that and see if I can tighten up any of the vaguries of the data. Another fuzzy area in my mind is they only let you pick single vs. dual plane intakes.

BTW the specs I'm planning for the engine are: 427 std bore, 10:1 compression, Ford -AA Solid lifter Cam, Medium Riser heads, Sidewinder intake, 750 doublepumper carb.

Anyone have flow bench data for the medium riser heads, or the Edelbrocks?

Thanks, Chuck

[Andy Dunn]

Here is the head flow data on all Edelbrock Heads. It is also on the Edelbrock site if you don't have a pdf reader.
http://www.racesearch.com/PDFCATALOGS/1602/118.pdf

It's generally easier to find the small block flow data. Here are some bb flow pages but the info looks slim
http://users.erols.com/srweiss/tablehdc.htm#Ford

Do you have more specs on your cam? I would like to try running the numbers as well but don't know much about that cam.

If you want more HP and TQ, focus all your attention on "heads and cam". Since you are still planning the engine, you can easily get way over 500 with the right edelbrock head and a good crane or comp cam. If you try to stick to authenticity, you will have to live with 350ish. You might be able to get a port job and mill compression to 10:5:1, but that's about it.

hope this info helps


Andy

[chuckbrandt]

Thanks for the Eldebrock link, that's just what I was looking for.

The cam I have is a NOS ford cam C3AZ-6250-AA and is supposedly the same as Crane Cam's "Blueprint" cam which is where I got these specs:

http://www.cranecams.com/master/apps/ford47.htm

Lift 0.524 intake and exhaust.
Intake (at 0.050) open 13 close 51
Exhaust (at 0.050) open 61 close 3
244 @ 0.050 intake and exhaust
114 lobe separation

BTW if I put in 11.5:1 compression I get 412 HP which I think is what the single 4 427 was rated.

Thanks again, Chuck

[Andy Dunn]

That first initial estimate you tried looks a little on the low side...maybe because of stock heads or maybe some data entry error. Here are some examples with the Edelbrock RPM FE heads which have the flow data posted to run good numbers. I like to select small tube header with open exhaust since I find it more closely approximates real world tests by siding on the conservative side.

Crane Cam 340321 (the one you spec'd above as stock)
http://www.cobralads.com/dyno2000/427bb1.gif

Crane Cam 340471
http://www.cobralads.com/dyno2000/427bb2.gif

Crane Cam 341191
http://www.cobralads.com/dyno2000/427bb3.gif

I am not sure how difficult it is, but if you can go to a roller (solid or hydraulic) it opens up the door to cams with more aggressive profiles like

Crane Cam 349541


It looks like all the cams above are fairly close but there is a 33HP difference from the stock one to the roller and 33 is a good chunk of HP to leave on the table.

You probably already know this, but just in case, I find the easiest way to get the cam data is from the number over the black diamond on the page you gave. See that 3 in a diamond...that is the crane part number....it is easier to use than the grind number of C3AZ-6250-AA. You can enter the part numbers here and get the cam spec card
http://www.cranecams.com/spectest.htm. The hardest part of desktop dyno for me was learning how to properly take the data off that card and put the numbers in the right places. The key is to always watch the .050 vs seat timing...I always prefer using the 050. Here is a tutorial that might help new dyno2000 users who are reading along.

I noticed on that edelbrock page that those heads can be milled to accept 2.19 and 1.73 valves. You might check around and see if that is a good idea. I tend to think it would make the heads flow a little better but it is best to check with a head guy on this.

hope this info is useful


Andy
http://www.cobralads.com

[chuckbrandt]

Which is probably the reason for it's pessimism. If you hit the port flow button after selecting that, you'll see those are some pretty lousy numbers. I would think stock Medium Riser heads would be much better, and infact the single number on the second website you gave me would confirm that. Measured at .600 the MR heads flowed 85 cfm more intake and 53 cfm more exhaust than the "Wedge / Stock Ports & Valves" setting. I'd think the Medium Riser would not be as good as the Edelbrock's though. BTW on the FE Big-Block Forum there was an interesting post of someone who did their own testing of the Edelbrock 6006 head and could not match the numbers that Edelbrock put out, kinda interesting.

http://www.network54.com/Forum/messa...geid=984787644

So I'm still on a quest for MR numbers but feel pretty good I'll have 400 HP anyway.

Thanks again, Chuck

[Andy Dunn]

Good points. I wish we could find more data in the FE components. Here is one thing that worries me about the head data on that one page...296/177 0.5980 608.9 hp for the medium riser and then 284/177 0.6232 584.2 hp for the high riser etc. These HP numbers are big and so I tend to think they are not stock. These might be ported heads since there is no additional info. I'll keep looking.

[chuckbrandt]

Those numbers really doesn't make much sense. I wonder if 10% less than the edelbrock's would be a fair approximation? Although they probably worked hard on the exhaust side which was a sticking point for all FE motors. I noticed Shelby is using exaust port plates on his 1300HP motor to improve the flow.

Hopefully someone will turn up some numbers for the MR heads. As you can probably tell I am trying to build this motor with 60s technology as much as I can. At least the first time through it. I want to put together as realistic an experience of having an original back in the day. That's why I chased down all these NOS parts.

Thanks again for your help!

Chuck

[A Snake]

Don't overlook Dove MR heads. They have tunnel port sized valves. I used them myself. I mated them to an original Shelby sidewinder manifold. Engine had 10.5:1 static compression and 11:1 dynamic compression. Carb is a tricked out 750 done by the Carb Shop. It flowed 910cfm after their rework. I don't have the cam specs. handy, but I do remember that it is split lift and duration and ground on 108 degree lobe centers. I think lift is .560 Intake -.580 Exhaust. I'll see if I can find all of the specs.

Done overlook the lobe separation as a factor. 108 is much more agressive than 114 with the same lift and duration. It idles rough at around 1000 rpm and smoothes out at 1400 to 1500.

It will run on pump supreme with the timing retarded but likes racing fuel with the spark up a bit. Quite a difference in how it runs too!

By the way, authenticy is nice, but draw the line at the Stellings & Helling air cleaner. It's fine at shows but we did a run on the dyno with it on and it took 60HP out of the motor! The engine didn't even sound the same!

My engine made 451hp@6100 and 471#ft@3800 through Butler mufflers and side pipes. Butler tells me that the mufflers are costing about 50hp. Given some miles on the engine, the HP numbers come up.

[chuckbrandt]

I had read on here the S&H was bad with the foam element but okay with K&N element. That's what I was planning on running. Which did you Dyno?

Thanks, Chuck