Reduced low lift flow from porting...

[Warp Speed]

I have no reason to talk about it??? It's been talked about to death, let it go.

I'm saying not everything needs a 50 degree.

Your the one that wants to argue about it.

I brought that up because I service his heads, he won, he's fast, and it proves not everything needs a 50.

I care too much? It's my living.

Poke my chest out? I gave an example. You are the problem Jay, period.

I'm the problem?!? Lol
I want to talk about the whys and how, you refuse.
Welcome back, the same old Chad!

The way you approach the situation is part of the problem. It's like you want to be argumentative. It's like you enjoy being combative. Especially towards people you disagree with.

Do you have anything technical to add?
I knew exactly how this thread was gonna go from the start, and here we go.....

[Warp Speed]

I have 3 different sets of heads in the shop with 60 degree seat.

I recently had some DRCE PS heads in the shop, no 60 there..

I feel I can make as much power with a 45 as I can with a 50 with my 23 degree stuff. Most of the Comp, big valve sportsman, are all 50 degree.

My 265cc 23 degree has a 50 degree seat.

These aren't some catalog cutters I use. I'll also say all of my 45 cutters have a 40 or more top cut. 35 is old news.

At this very moment, I am looking at a set of NASCAR SB2.2 heads from a many time championship team, they are 60 degree exhaust, probably 13-14 year old stuff.

Whenever the valve seat angle comes up, the exhaust is rarely referenced. I wonder why? Lol

[GARY C]

I'm the problem?!? Lol
I want to talk about the whys and how, you refuse.
Welcome back, the same old Chad!

The way you approach the situation is part of the problem. It's like you want to be argumentative. It's like you enjoy being combative. Especially towards people you disagree with.

Do you have anything technical to add?
I knew exactly how this thread was gonna go from the start, and here we go.....

What are the flow #'s on a cup car head and what is it at TDC? Just so we can keep this a tech discussion?

[GARY C]

I have 3 different sets of heads in the shop with 60 degree seat.

I recently had some DRCE PS heads in the shop, no 60 there..

I feel I can make as much power with a 45 as I can with a 50 with my 23 degree stuff. Most of the Comp, big valve sportsman, are all 50 degree.

My 265cc 23 degree has a 50 degree seat.

These aren't some catalog cutters I use. I'll also say all of my 45 cutters have a 40 or more top cut. 35 is old news.

At this very moment, I am looking at a set of NASCAR SB2.2 heads from a many time championship team, they are 60 degree exhaust, probably 13-14 year old stuff.

Whenever the valve seat angle comes up, the exhaust is rarely referenced. I wonder why? Lol

I ask the same thing every time the discussion is brought up, with no answer... So fill us in?

[Warp Speed]

The way you approach the situation is part of the problem. It's like you want to be argumentative. It's like you enjoy being combative. Especially towards people you disagree with.

Do you have anything technical to add?
I knew exactly how this thread was gonna go from the start, and here we go.....

What are the flow #'s on a cup car head and what is it at TDC? Just so we can keep this a tech discussion?

I obviously can't tell you exactly what our heads flow, but it's not uncommon to see a Cup head go 440+cfm. Not sure what you are referring to as far as TDC?

[Warp Speed]

At this very moment, I am looking at a set of NASCAR SB2.2 heads from a many time championship team, they are 60 degree exhaust, probably 13-14 year old stuff.

Whenever the valve seat angle comes up, the exhaust is rarely referenced. I wonder why? Lol

I ask the same thing every time the discussion is brought up, with no answer... So fill us in?

I dont have an answer, except maybe most think it is unimportant?!? Lol

[Stan Weiss]

Do you have anything technical to add?
I knew exactly how this thread was gonna go from the start, and here we go.....

What are the flow #'s on a cup car head and what is it at TDC? Just so we can keep this a tech discussion?

I obviously can't tell you exactly what our heads flow, but it's not uncommon to see a Cup head go 440+cfm. Not sure what you are referring to as far as TDC?

Jay,
You take the intake valve lift @ TDC and see what the head has for flow at that lift.

Stan

[Ron E]

We like 55° seats on the exhaust in almost any drag race application that is freshened yearly or more. The 55 allows a touch more duration giving increased duration at meaningful lifts. It works with big throats which helps make the port quieter. And, the higher lifts (subsonic) usually are better with steeper seats.

[PRH]

... I'll also say all of my 45 cutters have a 40 or more top cut. 35 is old news.

Can you comment on what you want to see as a transition from that type of top angle into the chamber?

Here are a couple pictures of a 15 degree Ford with a 40 top 50 and a 23 degree Dart with a 40 top 50. Same cutter. Then the third picture is a 40 top 45. I want to not feel any transition.

What do you do when the shape of the chambers are not anything “race inspired”, where there will definitely be a large portion of the perimeter of the valve seat that has to transition to a “0” deg area?
Like a Performer RPM for a BB Mopar....... or a factory Pontiac machined chamber.

Without sinking the valve a bunch, there simply isn’t enough material to work with to transition from a 40* top cut to the 0* chamber so you can’t feel it.

Like with that 305 stocker head......... which doesn’t have a 40* top cut.

[PRH]

Thats interesting, my 10.2 Chevy 2.05 headed 350 with a 262 XE vs my 9.2 Factory Pontiac 2.11 headed 412 with a 268 AH have almost the same overlap, 54/56 respectivly but my Pontiac is a bit more radical at idle at 2" lower in vacuum and requires at least 150 more rpm to idle despite being 62 ci bigger? both with 1.65 rockers an around .511 lift and similar head work around 240 CFM?

Sounds like you have the perfect opportunity to see just what losing some low lift flow by changing the valve seat angle will do to the power output if you change nothing else.

Put some 45* intake valves in the Pontiac heads and I’m sure you’ll be rewarded with higher idle vacuum.
Will that translate into additional power?
That’s the answer this test should provide........ and is at the root on the OP’s original question.

On a mild street combo like that........ is losing low lift flow a bad thing?

[SpeierRacingHeads]

Can you comment on what you want to see as a transition from that type of top angle into the chamber?

Here are a couple pictures of a 15 degree Ford with a 40 top 50 and a 23 degree Dart with a 40 top 50. Same cutter. Then the third picture is a 40 top 45. I want to not feel any transition.

What do you do when the shape of the chambers are not anything “race inspired”, where there will definitely be a large portion of the perimeter of the valve seat that has to transition to a “0” deg area?
Like a Performer RPM for a BB Mopar....... or a factory Pontiac machined chamber.

Without sinking the valve a bunch, there simply isn’t enough material to work with to transition from a 40* top cut to the 0* chamber so you can’t feel it.

Like with that 305 stocker head......... which doesn’t have a 40* top cut.

Your right, I put whatever top cut the chamber can take. But I will say, I don't work on too much factory stuff anymore.

I have a local, good friend, that runs a crate engine in his dirt mod at the local track. I didn't have a cutter. So I busted out the stones!

The stocker head was stones as well.

[PRH]

I put whatever top cut the chamber can take.

This is the core of my arguments about a lot of stuff that gets tossed around in forums.

Not all heads and/or combinations are suitable candidates to try and implement the latest trends being used on the newest, most advanced castings currently available.

And that point is often not talked about.

[RevTheory]

I put whatever top cut the chamber can take.

This is the core of my arguments about a lot of stuff that gets tossed around in forums.

Not all heads and/or combinations are suitable candidates to try and implement the latest trends being used on the newest, most advanced castings currently available.

And that point is often not talked about.

I couldn't agree more. Well said.

[SpeierRacingHeads]

I put whatever top cut the chamber can take.

This is the core of my arguments about a lot of stuff that gets tossed around in forums.

Not all heads and/or combinations are suitable candidates to try and implement the latest trends being used on the newest, most advanced castings currently available.

And that point is often not talked about.

I agree. What kills me is guys read that you need "this" or "that" seat and end up putting the wrong top cut on it and killing the head.

[Warp Speed]

What are the flow #'s on a cup car head and what is it at TDC? Just so we can keep this a tech discussion?

I obviously can't tell you exactly what our heads flow, but it's not uncommon to see a Cup head go 440+cfm. Not sure what you are referring to as far as TDC?

Jay,
You take the intake valve lift @ TDC and see what the head has for flow at that lift.

Stan

What is learned by this and how is it applied?