Camming a 409 sbc with small intake runner

[BowtieNut]

so how did the cnc machine cut through them if you ported them, high runner speed will benefit more with the 110lsa

Because I ported one port and digitized it on the cnc machine Then mirrored it on cad and used guide spacing for centers. So the cnc machine is going to put the port where it's suppose to be. As you already know with casting core shift you get variations from one head to the next. So all my mirrored ports cut most of the pinch out and I had to fill them back in with moroso a and b epoxy.

[Carnut1]

[/quote]
Bowtie, I like this project and would love to get any info on those heads. I will make a few assumptions and then give you my opinion. I will guess That the port is near 200 cc with a 2'' sq pinch point with about a 400 ft/ sec air speed through the pinch. I like this setup with a dual plane but VERY few dual planes can feed 300+ cfm. This engine is right on the ragged edge of dual plane performance. Is the intake ported? Is the head cut for a 1205 or a 1206 gasket?[/quote]
The square area at the pinch is 2.1 inches. I use the fell pro 1255 gasket and cut them to size. Dual plain is ported. The whole package flowed 277 at. 500 lift.[/quote


]Sorry, I forgot it was a vortec so different gasket. Good work on getting them to flow 277 cfm . Which intake? Carb size? Spacers? Are you opposed to a roller cam?

[Carnut1]

Just looking some opinions on a solid flat tappet can for my 10 to 1 409. It has the 062 vortex heads that I ported with 2.08/1.6 valves. They flow 304 at. 500 lift on intake and go flat beyond that. Exhaust went 227 at. 500. They flow real.strong down low .100 was 92 cfm. 200 was 187 cfm. I've had a couple different cams in it. Strongest was comps restricted application lobes. 282/256 .520 lift on intake and exhaust on a 108 Lsa. That made 513 HP at 6700 and 500 lb ft of torque at 4800. Motor ran a 6.38 at 103 mph in a 3100 lb nova. The problem I have is it goes flat anywhere from 5300 to 6000 then gets a second wind and jumps up another 20 HP up to around 6800. Anyone had a scenario such as this before. You couldn't tell at any point on the race track that it was flat. Leaves with a 1.38 60 ft and pulls hard out the big end. The cam i have in it now is a 265/236 .532 int 265/240 .562 exhaust on 112 lsa with a dual plain instead of the single plain. That combo made 488 HP at 6200 and 503 lb ft of torque at 4300 . I haven't ran that can yet at the track but I'm thinking of going back to something bigger. Car weighs 3200 5.13 gears and a Hughes 4000 stall.

It is interesting that the motor goes flat right when the imep is at its peak. Someone else said on another thread that it could be detonation that caused a strange shaped curve. If your cylinder pressure and spark curve or fuel curve don't shake hands power will be lost. How do the plugs look?

[BowtieNut]

Bowtie, I like this project and would love to get any info on those heads. I will make a few assumptions and then give you my opinion. I will guess That the port is near 200 cc with a 2'' sq pinch point with about a 400 ft/ sec air speed through the pinch. I like this setup with a dual plane but VERY few dual planes can feed 300+ cfm. This engine is right on the ragged edge of dual plane performance. Is the intake ported? Is the head cut for a 1205 or a 1206 gasket?[/quote]
The square area at the pinch is 2.1 inches. I use the fell pro 1255 gasket and cut them to size. Dual plain is ported. The whole package flowed 277 at. 500 lift.[/quote


]Sorry, I forgot it was a vortec so different gasket. Good work on getting them to flow 277 cfm . Which intake? Carb size? Spacers? Are you opposed to a roller cam?[/quote]
My dual plain is a airgap performer rpm. Single plain is a hurricane. Carb is a 750 HP Holley. Also have a edelbrock 750 that I tricked out. It's about 10 HP down from the Holley but the throttle response of the Edelbrick is hard to beat. I'm actually planning to see the what the Et difference is between the two.

[steve cowan]

304 cfm @ 0.500 lift on a 062 vortec head,like joe mondelo said (rip) you are crazy or you are smoking dope-end of story.

[BowtieNut]

304 cfm @ 0.500 lift on a 062 vortec head,like joe mondelo said (rip) you are crazy or you are smoking dope-end of story.

Haha well you believe what you want. The fact that it makes nearly 490 HP with a dual plain manifold and a cam with overlap degrees only in the high 40s should be an indication that they are moving some air in the low lifts. The cam that's in it will literally idle smooth as butter if I loosen the lash up to anything wider than .024. I figured someone would raise the BS flag on me haha.

[Carnut1]

304 cfm @ 0.500 lift on a 062 vortec head,like joe mondelo said (rip) you are crazy or you are smoking dope-end of story.

Haha well you believe what you want. The fact that it makes nearly 490 HP with a dual plain manifold and a cam with overlap degrees only in the high 40s should be an indication that they are moving some air in the low lifts. The cam that's in it will literally idle smooth as butter if I loosen the lash up to anything wider than .024. I figured someone would raise the BS flag on me haha.

Well Bowtie, I believe you and would love to see some pictures of your work.

[af2]

304 cfm @ 0.500 lift on a 062 vortec . I figured someone would raise the BS flag on me haha.

When a named person like Larry Meux would give his right grinding finger to get 280 with those heads at .600" yes the flag is up..

[Carnut1]

304 cfm @ 0.500 lift on a 062 vortec . I figured someone would raise the BS flag on me haha.

When a named person like Larry Meux would give his right grinding finger to get 280 with those heads at .600" yes the flag is up..

I have seen where Larry has gotten 275 cfm out of 041 castings. If the 062 are opened to about a 200 cc with a 2.1" pinch and a 2.08" valve 304 is possible but I feel the airspeed is a bit high for a 409 @ 7000rpm.

[zums]

If the 062 are opened to about a 200 cc with a 2.1" pinch and a 2.08" valve 304 is possible .[quote][/quote]- not without visiting the water jacket

[Carnut1]

If the 062 are opened to about a 200 cc with a 2.1" pinch and a 2.08" valve 304 is possible .

- not without visiting the water jacket

That would require a nearly 30 cc iron removal and some serious sonic sonic checking for sure.

[zums]

not to mention how close the valve margins are, assuming stock guide centers

[greywolf]

cylinder head pictures at some point would be nice!!!

[BowtieNut]

Here's a few pics of them.

[BowtieNut]

A few more pics.