30 vs 45 degre valves?

[Heo]

The edelbrock and stock C.J intake  valves is 30.deg
427 also i Think. Ford had some reason to use 30 deg
valve on hp Engines. Mercedes use 30 also
Old hopup tricks for the flathead recomend 30 deg

but i saw here the delbrock heads gain much from
changing over to 45 deg? wich valves is used  for that
I have only found 30 deg cobrajet sized valves

Im about to get some C4-G heads ported witch deg
to use 30 or 45

[fastback 427]

When we did some porting on our fe heads, the 30° had much better low lift flow than the 45°. After about 400 lift the 45° took over. At 600 lift there was a 45 cfm gain by using 45°. I would assume that ford and ebock use the 30° for better street performance. I'm sure Joe d craine or many others can give you a much better answer.

[Heo]

Thank you FB 427.
Anyone else that have something to ad?

[Joe-jdc]

I have done 390/C6AE-R valve jobs in angles from 25/30/35/40/45/50/55* on both the intake and exhaust valves.  The shallower the angle, the better the flow at low lifts/ the steeper the angle the better the flow at higher lifts---to a point.  The combustion chamber shape will determine how well this works, as well as the shape of the valve in the tulip area.  Think this way---the less difference in turns into the chamber, and the less turns the airflow makes over the valve, the more flow will increase.  If the short turn is shaped wrong(FE), all this goes out the window because the airflow will shear and cling to the short turn and the port will go turbulent no matter what the angle of the valve job.  Joe-JDC. 

[Heo]

Well then i see why. Since few flatheadcams reached .400 in lift
And CJ,481 and most 427 cams at 500 they probably had best
"total"flow with 30 deg seat....
If we take for example compcams 282S/294S with 571/605 lift
whats your opinion are they better of with 30 or 45 deg.
And are there any fitting valves around 2.10 dia or do i take
2.19 427 valves and grind down?

And Another thing i was examing the heads around the exhaust
seats thinking about fitting hardened valveseats. But there is
not much material left for suport if you mill for a new seat.
Any one here that have mounted seats in C4-G heads with
sucsess??
Yess i know im better of buying new alu heads
But i traded a Volvo Amazon that i had sitting and rotting
for all the headwork

[Ford428CJ]

Well then i see why. Since few flatheadcams reached .400 in lift
And CJ,481 and most 427 cams at 500 they probably had best
"total"flow with 30 deg seat....
If we take for example compcams 282S/294S with 571/605 lift
whats your opinion are they better of with 30 or 45 deg.
And are there any fitting valves around 2.10 dia or do i take
2.19 427 valves and grind down?

And Another thing i was examing the heads around the exhaust
seats thinking about fitting hardened valveseats. But there is
not much material left for suport if you mill for a new seat.
Any one here that have mounted seats in C4-G heads with
sucsess??
Yess i know im better of buying new alu heads
But i traded a Volvo Amazon that i had sitting and rotting
for all the headwork

If your running a 282 or the 292, I do believe the 45's would be the better choice at that lift. Otherwise if you had a 30 with .600, the air would dirty up. I may be wrong and Joe would correct me if I am.

As for the Valves... We took 427 size valves from 2.19 to 2.15 & 1.75 to 1.73 (C4AE-G heads) for the Poor Mans. Seam to work well for our build. But if your talking about 2.10... Why not buy a set of CJ valves (2.09, 1.65) for your C4AE-G heads? There would be plenty materiel in the head to support that size! But if you did what we did (2.15 & 1.73) was tight and not much room for the exhaust side of the house. 

Whats the bore size of the engine?  That has a effect on valve size as well.... JMHO

[Heo]

I have bought a set of 2.09 CJ valves but the intake is 30 deg and
if i grind them to 45 then they are back to stock size
and i have not found any CJ valves with 45 deg intake
the bore is 4.11 and i have not tried how big valve i can
use with out the cyl. scrouding the valve
maby i can go bigger than 2.09
Only thing i know is back in the dark ages (the 80s)
I built a couple of +.030, 390s with CJ valves in C4-G heads
it was said then to not go bigger valves in a street 390
But today there is different cams availibel and better
know how about airflow and headporting
So im open for all sugestions i can get

What im trying to build is a strong street Engine for a Galaxie
with somewhat decent low rpm behavior
Im not aiming for fame and glory with this engine

[bn69stang]

I have been told by gentleman here in Albuquerque that he can improve my stock edelbrocks by about 12% - 15% with stock valves and 30 degree seats for around 500.00 , I am looking forward to having the heads done and swapping to a hyd roller cam . He s been doing heads for 30 -35 years . So i think you can use the 30 degree seats and improve flow and still have low end tq and hp .. Bud

[Ford428CJ]

I know that a Nail Head Valve on the intake side will help flow. Like the stock FoMoCo  intake valve
 

[ScotiaFE]

I have been told by gentleman here in Albuquerque that he can improve my stock edelbrocks by about 12% - 15% with stock valves and 30 degree seats for around 500.00 , I am looking forward to having the heads done and swapping to a hyd roller cam . He s been doing heads for 30 -35 years . So i think you can use the 30 degree seats and improve flow and still have low end tq and hp .. Bud

You could do the same for about 30 bucks and a good day at the bench if you have a die grinder at your disposal.
He would be doing nothing more than a home bench port job. just saying.

[plovett]

Here's what my ported Eboks flowed, going from a 30 degree seat to a 45 degree seat:

Lift-----30-degree-----45-degree
0.050-----36.0-----------26.9
0.100-----72.1-----------61.7
0.200----141.9----------129.3
0.300----193.0----------190.4
0.400----222.7----------236.1
0.500----259.6----------267.3
0.550----no-data------- 281.3
0.600----278.6----------293.4
0.650----279.8----------302.8

You can see that the 45 degree seat starts flowing better somewhere after .300" lift.  Just FYI.

paulie

[My427stang]

I think 12% for 500 with a fresh valve job is pretty cheap

If a stock Edelbrock flows 248 intake / 214 exhaust at .600 (sort of a WAG number) then 112% of that would be 277 intake / 240 exhaust.

That second head could potentially support 50 more horsepower with the right combo.  pretty cheap!

Paulie's numbers back that up too

[bn69stang]

I get what you are saying Howie but with out a flow bench how would i know just what or how much improving im doing , or hurting ? l have never ground on any heads , im sure if i watched it then i would have a better idea . which is what i plan on doing and i know its not difficult , i guess i need a practice head  lol  Bud

[Joe-jdc]

Stock Edelbrock heads will not flow 200cfm at any lift on the exhaust.  Most only flow in the low 180cfm, and occasionally 190-191cfm @ .750" or higher.  (CJ style with 1.665 exhaust valve)  It is actually not easy to get 220cfm, much less 240 without going to 1.710 or larger valves.  Joe-JDC.

[My427stang]

Stock Edelbrock heads will not flow 200cfm at any lift on the exhaust.  Most only flow in the low 180cfm, and occasionally 190-191cfm @ .750" or higher.  (CJ style with 1.665 exhaust valve)  It is actually not easy to get 220cfm, much less 240 without going to 1.710 or larger valves.  Joe-JDC.

That number just came off of Stan's site, that's why I mentioned it was a WAG.

My point was 12% of flow is a huge amount for the cost of a good valve job, and I doubt a little rubbing by a novice home porter will keep up with that