manifold to head matching

[crenbbf]

Hi All

Here are our port to gasket match ups





What are your thoughts on matching up the manifold to the heads?

I understand a step from the manifold to head can be an advantage

What do you think?

PS ignore the chocolate rockers

cheers

[RICK LAKE]

crenbbf Cren nice work on the head ports. You can see how far out the intake is. I don't know what manifold you are running but having it ported and have the cfm all the same in each cylinder would help. No sure if you want but Joe Craine does this to any FE manifold and gets all the ports within a couple of cfm. Stock manifold can be as far out as 30-40 cfm between ports. I had mine done and so have a couple of others here. Helps the motor. There is a lean cylinder on FE's. Think it's 7 or 8. Joe fixes this. He has done alot of manifolds on the FE forumn.com also. The manifold came back looking too good to but on the motor. Wanted to leave it on the coffee table. It's a bla ck art to get each cylinder with the same fuel/air. it's just a suggestion. Turn around is 1 week. Cost is low for all the work. Shipping about $65.00 each way. Good luck. I don't have a picture to show of how he shapes the inlet to get each port the same amount of air/fuel, it's custom. Rick L.

[blykins]

Well, you have a mismatch, but it's not a really bad mismatch. You may be leaving a few ponies on the table, but the roof of the intake runner is below the roof of the cylinder head port, so you're not going to see any "bad" symptoms there.

I've seen engines built by other builders where if you were to look down into the intake with a scope, you'd see cylinder head sticking into the intake runner. You can imagine that if the air/fuel charge were heading down the runner, it would "hit a wall" and it would possibly cause some reversion.

In your scenario, you have a mismatch, but the intake opening is essentially smaller than the head opening. Depending on the size of the engine and the intake you're working with, this may not necessarily be a bad thing. Sometimes velocity is good...

[crenbbf]

Hi Rick

Thanks again for the reply,The manifold is an Offy single plane dual quad.

Which in hindsight probably wasn't the best choice(a pattern emerging here)

TBH I can't take any credit for the head work but it be a shame not to take advantage of the port size.

The problem would be shipping from sunny Scotland and back again, it would probably be cheaper to just buy another.

cheers Kiel

[crenbbf]

Originally Posted by blykins

Well, you have a mismatch, but it's not a really bad mismatch. You may be leaving a few ponies on the table, but the roof of the intake runner is below the roof of the cylinder head port, so you're not going to see any "bad" symptoms there.

I've seen engines built by other builders where if you were to look down into the intake with a scope, you'd see cylinder head sticking into the intake runner. You can imagine that if the air/fuel charge were heading down the runner, it would "hit a wall" and it would possibly cause some reversion.

In your scenario, you have a mismatch, but the intake opening is essentially smaller than the head opening. Depending on the size of the engine and the intake you're working with, this may not necessarily be a bad thing. Sometimes velocity is good...

Hi Brent

I was more concerned with the ports not being centred compared to the heads would this be an issue?

cheers Kiel

[CHANMADD]

Get a grinder and smooth the trransition ......imagine the throat of the carb.....ie the venturi.......ifvthe intake port has a narrowing at the join it will work like a venturi..if so shaped...which speeds up the gases at the exit....which is right at the valve ....so some gain for sure.....making them all the same is going to make it run smoother.....

[RICK LAKE]

crenbbf Cren you can do a cleaning up yourself. Chan has it right. You need red or blue machinist dye and paint the ports. Put the gasket over the manifold and scribe the line out on the side of the gasket. Big thing here. Make sure the gasket doesn't move. Center the bolt hole on the manifold also. Grind out within 1/16" all the way around the port. DON'T worry about the bottom of the port, ( it is dead air and has low flow ) 1/4 up to top 1/8" is where the major flow is. You want to remove little as possible to match. Go into port about 1" and blend the port out. Have to watch the pushrod channel. There is not alot of metal to grindout. Sand smooth the port when done. If you can get a inside caliper to check port metal thickness. I don't know what the max thinness is but guess about .075". I know that head and intake manifold ports make up templates of metal or cardboard to keep unified from 1" in the port and have 2 or 3 to the out side of the port. If you do make like the pushrod holes, welding and installing sleeves to seal from a vacuum leak is possible. I have this done on 1 of my manifolds. Others here have the same thing to get max flow out of an intake. If worried. go to a junk yard and get a crap manifold of anything and practice. you can get used to the grinder and the bit you are using. This is not a 10 minute job. Will take about 1/2 hour start to finish. Stay inside your lines. Good luck. Rick L.

[crenbbf]

Originally Posted by CHANMADD

Get a grinder and smooth the trransition ......imagine the throat of the carb.....ie the venturi.......ifvthe intake port has a narrowing at the join it will work like a venturi..if so shaped...which speeds up the gases at the exit....which is right at the valve ....so some gain for sure.....making them all the same is going to make it run smoother.....

Originally Posted by RICK LAKE

crenbbf Cren you can do a cleaning up yourself. Chan has it right. You need red or blue machinist dye and paint the ports. Put the gasket over the manifold and scribe the line out on the side of the gasket. Big thing here. Make sure the gasket doesn't move. Center the bolt hole on the manifold also. Grind out within 1/16" all the way around the port. DON'T worry about the bottom of the port, ( it is dead air and has low flow ) 1/4 up to top 1/8" is where the major flow is. You want to remove little as possible to match. Go into port about 1" and blend the port out. Have to watch the pushrod channel. There is not alot of metal to grindout. Sand smooth the port when done. If you can get a inside caliper to check port metal thickness. I don't know what the max thinness is but guess about .075". I know that head and intake manifold ports make up templates of metal or cardboard to keep unified from 1" in the port and have 2 or 3 to the out side of the port. If you do make like the pushrod holes, welding and installing sleeves to seal from a vacuum leak is possible. I have this done on 1 of my manifolds. Others here have the same thing to get max flow out of an intake. If worried. go to a junk yard and get a crap manifold of anything and practice. you can get used to the grinder and the bit you are using. This is not a 10 minute job. Will take about 1/2 hour start to finish. Stay inside your lines. Good luck. Rick L.

Thanks Guys

I thinking that it's not worth the bother to change things this being a street car only.

As Brent says we'd only be losing a few horses anyway.

cheers Kiel

[tcabece427]

My guess is the block has been decked. Much of the documentation on the 427 shows a deck height of 10.17". That's not how Ford manufactured many of them. I have a 1972 427 service block and its deck height it 10.19. I had my machinist check this and the piston manufacture. 10.19 is what the piston manufacture (Keith Black) built their compression ratios around. The intake I have Blue Thunder also bolts up fine with no "step" between the head and intake and there is room for the cork gasket at the valley looks like about .125" to .187". The only way to make the intake "fit" properly on a block that's been decked. Is to mill each side and the front and back of the intake. Typically the block at the valley front and back was not milled/decked. Just the top of the cylinder heads.
If you're interested I do have a Ford Police Interceptor intake that has been milled for a 10.17 deck height block.