302's with 1.88's... thumbs up or thumbs down, lets see your pics

[MOPAROFFICIAL]

Would gasket matching help or make any significant difference when using a 318 intake like a performer or LD4B or Holley street dominator? (Against the 318/273 heads that you just ported)

Would the head to intake holes typically one up despite the gasket size designed for a 340/360/++ ?

So here's what's up.. you would think that if the port on the head was smaller then the intake manifold port window, despite its misshapeness, that it wouldn't matter.. but it does. When the incoming volume of air hits that ledge ..it tumbles.. and when it tumbles it slows and gets in the way of oncoming air and the flow is less.
Take some old steel 318 intake gaskets that have the centering holes already on them, lay them on and mist it with spray paint.. and you grind where the paint is around the Port window.
Thank you for mentioning me and I'm glad I can inspire you or teach you something, so here I am helping you along some more.

Once the intake Port window on the head becomes larger than the intake manifold port window, the intake manifold is now the limiter. You'll no longer have a lip the air to trip over and Tumble. So you're oddly enough better to be bigger at the Port window of the head than the intake manifold.. but the same effect occurs of flow interference.. and you're now also toying with velocity... so it becomes a how much smaller is the intake manifolds Port window in relation to the heads Port window.. and vice versa.
This is why it's better to match them or have them within about .030

 

[jrc4y4]

Well that's great.. but did you watch the part about gasket matching? Did I leave that out??

Man it’s been a few years so tbh I forget if I saw that video. I was under the impression not to take out too much on the floor so I didn’t go all the way down. And felt where the gasket ended left it way too thin so I stopped where I stopped.

FWIW I have a performer intake and tried to match the ports close to what was done on the head side.

Also I figured with the pushrods in the way I didn’t think it was worth the time to extend the openings further out than I did. Or am I wrong in this thinking? Won’t hurt my feelings to tell me. I’m sure I left power on the table but this was my first experience porting anything. And really happy with the results.

 

[273]

Man it’s been a few years so tbh I forget if I saw that video. I was under the impression not to take out too much on the floor so I didn’t go all the way down. And felt where the gasket ended left it way too thin so I stopped where I stopped.

FWIW I have a performer intake and tried to match the ports close to what was done on the head side.

Also I figured with the pushrods in the way I didn’t think it was worth the time to extend the openings further out than I did. Or am I wrong in this thinking? Won’t hurt my feelings to tell me. I’m sure I left power on the table but this was my first experience porting anything. And really happy with the results.

From what I understand the roof and dividing wall are the most important.

 

[jrc4y4]

From what I understand the roof and dividing wall are the most important.

As in take off more off the roof and focus on shaping the roof? And the floor isn’t as important to shave off?

 

[273]

As in take off more off the roof and focus on shaping the roof? And the floor isn’t as important to shave off?

As in the roof and dividing wall on intake and head should have same opening it is where most the air flows so it should be where most gains are compared to floor and pinch, but don’t mean there’s no gains to be had there.

 

[jrc4y4]

Well I went back to my way old post about the port job. Turns out @MOPAROFFICIAL helped me on that post a lot lol. Sorry to beat a dead horse. Memory failing me haha. Anyway. No idea what they flow or anything but the car responded significantly.

 

[jrc4y4]

Best pics I could find. I assume there’s room for improvement, but if I ever do that much work on heads again, it’ll be for a 340/360 build with better heads to begin with. That said, happy with how these turned out on the 318.

 

[Hysteric]

Port matching the manifold to the head only encourages the fuel that is on the walls to stay there and it travels slower than the column of air. You need to keep the fuel entrained in the air column as that's what provides the best mixture.

One of the smartest guys in the game makes the manifold slightly smaller than the cylinder head runner so as to keep the fuel entrained in the air. I remember Joe Sherman saying on Speedtalk that a Big Block Chevy with a port misalignment (peanut to square from memory) made more power. If the air was that important it would have made less......

Another well know engine builder has seen smaller intake manifolds port runners that would have theoretically restricted air flow to the head actually make more power.

A flow bench tells you what the air is doing........What tells you what the fuel is doing?

 

[273]

What tells you what the fuel is doing?

Apparently you

 

[MOPAROFFICIAL]

Port matching the manifold to the head only encourages the fuel that is on the walls to stay there and it travels slower than the column of air. You need to keep the fuel entrained in the air column as that's what provides the best mixture.

One of the smartest guys in the game makes the manifold slightly smaller than the cylinder head runner so as to keep the fuel entrained in the air. I remember Joe Sherman saying on Speedtalk that a Big Block Chevy with a port misalignment (peanut to square from memory) made more power. If the air was that important it would have made less......

Another well know engine builder has seen smaller intake manifolds port runners that would have theoretically restricted air flow to the head actually make more power.

A flow bench tells you what the air is doing........What tells you what the fuel is doing?

The back of the valve is one 1st hand witness. Big block Chevys mismatch intake could have something to do with where the airspeed is dead in the first place, like saying the same thing a different way ...whatever end you want to look at it, who can prove it this or that... go ahead, but do it with your findings. Nice to see you again, mate..

 

[MOPAROFFICIAL]

Apparently you

The game is pretty obvious, isn't it

 

[fishmens67]

One of the smartest guys in the game

I know that guy.

 

[Deltatech]

Since these needed new guides and had to go to the machinist anyway, I widened the pinch and gasket closed. Smoothed some of the casting and stream lined the guides a little. It's a night and day difference in the seat of your pants from stock 302's,cast intake and 2 barrel to mild port gasket closed to 360 sized, gasket closed rpm air gap intake and 4 barrel.
The car stock would barely brake torque and wouldn't spin em much from a stop at full throttle before, after it'd brake torque or spin em from a full stop at 1/2 throttle.

 

[MOPAROFFICIAL]

So many people don't know the difference between torque and horsepower or what they do

 

[RustyRatRod]

So many people don't know the difference between torque and horsepower or what they do

So, would there be any advantage to 2.02s in a 302 casting? Could they even be ported to support that?

 

[273]

So many people don't know the difference between torque and horsepower or what they do

Agree, The formula pretty much tells it, HP = torque x rpm / 5252 or plainly said HP is (=) Torque and RPM and vice versa, There's no verses or one does this and the other does that.

 

[273]

So, would there be any advantage to 2.02s in a 302 casting? Could they even be ported to support that?

I read they did really good on one of those magazine 400 hp 318's, If I remember it right it made the most torque and took the smallest cam to hit 400 hp, but apparently they developed a leak.

 

[MOPAROFFICIAL]

So, would there be any advantage to 2.02s in a 302 casting? Could they even be ported to support that?

Bigger valves help any head, to a point.

Support what? The flow potential of a 2.02 valve? 290 something cfm?

Nope.

 

[RustyRatRod]

Bigger valves help any head, to a point.

Support what? The flow potential of a 2.02 valve? 290 something cfm?

Nope.

Yes. Support the 2.02 valve. That's what I asked about. I sure wasn't talkin about a 1.78 when I said 2.02.

 

[273]

https://www.hotrod.com/articles/318-small-block-build

Junkyard Jewel 318 Power Curves
RPM	TEST 1		TEST 2		TEST 3
	Torque	HP	Torque	HP	Torque	HP
3,000	334.9	191.3	354.1	202.3	349.1	199.4
3,500	360.7	240.4	378.2	252.0	380.7	253.7
4,000	376.6	286.8	402.3	306.4	401.5	305.8
4,100	379.3	296.1	402.4	314.1	401.6	313.5
4,500	374.0	320.4	402.5	344.9	400.1	342.8
4,600	374.0	327.6	403.1	353.0	400.6	350.9
4,700	373.5	334.2	400.6	358.4	408.0	365.1
5,000	363.9	346.4	389.7	371.0	402.0	382.7
5,500	344.0	360.2	368.3	385.7	386.5	404.8
5,900	331.1	372.0	347.1	390.0	361.4	406.0
6,000	328.3	375.0	344.0	393.0	353.8	404.2
6,100	319.4	371.0	339.2	394.0	347.8	404.0

 

[MOPAROFFICIAL]

Yes. Support the 2.02 valve. That's what I asked about. I sure wasn't talkin about a 1.78 when I said 2.02.

Of course... but for informative purposes I spelled it out.

 

[MOPAROFFICIAL]

200 cfm