Some M1 porting pictures and flow numbers

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pittsburghracer

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I have a gentleman’s Edelbrock heads on the flowbench so this was a great time to do some porting on a small block Mopar M1 manifold. He provided a one inch spacer and it had a bulge in the front of the manifold so knowing anyone would do their best to have it removed I did so before I did my before flow testing. Zero shaping was done just quickly remove the over 3/16 bulge. Before picture. The customer gave me permission to post up the progress so I’m sure he will be dropping in.

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The first thing I noticed were how small the runners are. I usually stuff red shop rags in the ports that aren’t getting flowed to limit flow through the port being tested. The red shop rags were way too big so a visit to my rag drawer I grabbed a handful of white half socks that I save after washing if they have holes in them. A full length white sock was too big so I didn’t expect big flow numbers on a 300 plus 2.055 valve Edelbrock head. Having never touched one before in my life the numbers surprised me for an untouched manifold. This intake would make some horsepower but hopefully we can get some top lift numbers to come up some. More pictures later as it’s time to unbolt this thing and fire up the grinder. 60 plus degrees tomorrow so I’m hitting the pistol range. I need this bad.

——-Head————intake on
.100—64——————62
.200—125—————125
.300—187—————183
.350—214—————213
.400—238—————236
.450—257—————246
.500—284—————255
.550—294—————256
.600—296—————258
.650—302—————271
.700—308—————279
 
Should horsepower potential be based on flow with the intake instead of heads alone?
 
Yes it does!

At that point I look at it as one piece. That why I offer a discount if doing both heads and intake and offer free spacer blending. In this case the customer has ported heads so he supplies his intake gaskets to match to the ports. Here’s a couple before pictures. I hope that didn’t come across smart assie but I never flow an intake by itself.

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Ok one side gasket matching roughed in and the other side 80% done. Getting hungry as I only snacked today so I’m not sure I’ll finish it.

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Greetings world at large! This would be my intake manifold being ported. I think this will prove to be interesting.
Thanks for the “Gentlemen” compliment. Now that cats out of the bag….. dang it! LOL!

Oh! I just remember! I forgot! What runner are you testing on?
 
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Anxiously waiting results while you dine…
Going on 8Pm and I’m heading for the house. Productive day in the shop. Finished roughing the other side so I’m done for the night. Like I said I’m going shooting tomorrow.
Greetings world at large! This would be my intake manifold being ported. I think this will prove to be interesting.
Thanks for the “Gentlemen” compliment. Now that cats out of the bag….. dang it! LOL!

Oh! I just remember! I forgot! What runner are you testing on?


You never said so I picked it for you. It will be what I consider number 4 for the duration.

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OK cool! Thanks. I wasn’t picky on which port was reported. The before and after is the tale of the tape everyone will be most interested in. A comparison to the Victor is what everyone will do.

Good luck fishing tonight!
 
Hey John, how far are you planning to go up the intake to blend for the gasket matching?
 
I had eddy heads/M1 ported polished gasket matched. Added roller rockers per eddy instructions and I dont believe it made a difference in anything other than aesthetics. Alot of money spent to make the runners look smooth. MP 380hp crate motor
 
I had eddy heads/M1 ported polished gasket matched. Added roller rockers per eddy instructions and I dont believe it made a difference in anything other than aesthetics. Alot of money spent to make the runners look smooth. MP 380hp crate motor
IN my humble opinion the two problems that come to light are:

Smoothed runners don’t make power.
The MP 360/380 engine has a street cam in it. 230@050 is small.
Were the heads stock? If so, that’s problem #3.
 
I had eddy heads/M1 ported polished gasket matched. Added roller rockers per eddy instructions and I dont believe it made a difference in anything other than aesthetics. Alot of money spent to make the runners look smooth. MP 380hp crate motor


Wow I wish you would have told us this yesterday. You would have saved my customer 300.00 and me a lot of time and work. Did your gas mileage increase any.
 
Should horsepower potential be based on flow with the intake instead of heads alone?
You can guesstimate HP based on cylinder head flow. The old layman’s way is cfm X 2 = approximate HP for a good street strip engine. It’s a basic formula that is not accurate but ball parks potentially what can be done.

The trick is using an intake that will allow the head to flow its maximum.

If you have a set of heads like what John ports these aluminum heads to, let’s round it at 300 cfm. It has the potential of 600hp.
It’s not getting there with a cast iron TQ intake. With the OOTB M1 bolted to the ported heads, he came up with 271 cfm @ .650 lift. This has the potential of 542 hp.

Can more power be made? Yes.
If all becomes how and what the combo is consisting of.

To reach 542 hp on a 360, it will need a reasonably sizable camshaft and compression to back it up with a good exhaust. Etc, etc, etc…..
 
You can guesstimate HP based on cylinder head flow. The old layman’s way is cfm X 2 = approximate HP for a good street strip engine. It’s a basic formula that is not accurate but ball parks potentially what can be done.

The trick is using an intake that will allow the head to flow its maximum.

If you have a set of heads like what John ports these aluminum heads to, let’s round it at 300 cfm. It has the potential of 600hp.
It’s not getting there with a cast iron TQ intake. With the OOTB M1 bolted to the ported heads, he came up with 271 cfm @ .650 lift. This has the potential of 542 hp.

Can more power be made? Yes.
If all becomes how and what the combo is consisting of.

To reach 542 hp on a 360, it will need a reasonably sizable camshaft and compression to back it up with a good exhaust. Etc, etc, etc…..
Got it! I based my hp potential on head flow alone. Now I know.
 
Well, it’s an old hot rodders guesstimate route. There’s so much more to this that it’s a bit crazy to write out and explain. Flow numbers aren’t everything and the size & shape of the head/intake ports are another side to the coin. That’s just the induction side of it and only the parts that are moving the air - minus the carb and above it - with the exhaust side and cam/valve train items as well.

At least when you get or shop for a set of heads you can normally find out their air flow numbers. Provided it’s a quality report on a quality port, the next thing you’re looking at is the size of the port. The CSA - Cross Sectional Area

The aspects of a cylinder head are simple but not simple. When you do a deep dive into what’s going on and how things get done and how changes affect everything, you suddenly realize that your neck deep and about to drown in an information overload.
Take a sip at a time to drain the lake.
 
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