[gtofreek]

I just finished rebuilding some Edelbrock round port heads. Someone had valve jobbed them before with a 30° intake seat, and then somewhat ported them. I flowed them as they were when they came in, and again after I redid the valve job with a 45° seat, like they should have had. They had the exhaust seat cut with a radius cutter. I redid it with our radius exhaust seat cutter. I added a 30° back cut to the new Ferrea valves.

Here is what they did as they came in.

_Lift____In____Ex
.100____88____66
.150___131____94
.200___166___119
.250___186___142
.300___195___163
.350___208___182
.400___222___197
.450___233___209
.500___246___218
.550___254___222
.600___261___226
.650___266___229
.700___269___232
.750___272___234
.800___274___236
Avg.=__218__185

Here is after a valve job only.

_Lift____In____Ex_______gain/loss
.100____74____71_______-14/+5
.150___113___101_______-18/+7
.200___147___125_______-19/+6
.250___180___145________-6/+3
.300___209___166_______+14/+3
.350___236___184_______+28/+2
.400___255___202_______+33/+5
.450___270___211_______+37/+2
.500___283___217_______+37/-1
.550___292___220_______+38/-2
.600___298___223_______+37/-3
.650___302___227_______+36/-2
.700___305___229_______+36/-3
.750___305___231_______+33/-3
.800___306___232_______+32/-4
Avg.=__238___186______+20/+1

This engine will be turbo charged, and run a valve lift of around .600", so the average to his valve lift would be:

199/167 for the 30° seat, and 214/170 for the 45° seat.

I went on to tune up the port job and ended up with 316 on the intake @ .600" lift, and it peaked at 321. This is with a port match to the RAIV Fel-Pro # 1233 intake gasket. I have the flow sheet for it ported at work. Forgot to bring that one home. I can post it later.

[Tom Vaught]

When they put the 30 degree seat on the heads they basically wound up with less flow than a out of the box e-head. Typical.

Good Job Paul.

Tom V.

[gtofreek]

The only reason I can see to use the 30° seat is if they ran a low lift cam, like a stock 068 or something. The 30° really helps the low lift numbers.

Here's a couple of pics of the seat before, and after.

[Squidward]

Paul, I promise: I will let you do all of my cylinder heads.

Nice!

Can't wait to put my 47's on my 400. I'm breaking in my big valve (#12's) 350 as we speak. You cleaned those up.

I always get nervous on a break in. I already found a tranny cooler line I forgot to put a hose clamp on.

[torqjunki]

Very nice. Easily the most important area for good flow. Bad valve job can negate some good port work. Good job Paul

[gtofreek]

Here is a comparison between my 670 heads, and these Edelbrock heads. I only have flow numbers to .450 lift right now. I have the higher lift numbers at work.


____670__________Edelbrock_____
_Lift_________CFM

.100"____71_________74
.150"____105.4______113
.200"____146_______147
.250"____185_______180
.300"____219.8_____209
.350"____247.1_____236
.400"____265.5_____255
.450"____273.8_____270

AVG,____189.2_____185.5

Pontiac Power! And to think this was done with only a 175 CC runner!

[torqjunki]

Wow!

[mgarblik]

We can see the benefit of the 30 degree intake seat even when applied incorrectly to the E heads. The factory, with the much smaller ports, smaller throat and max lift of .407 would probably be better than a 45 degree most of the way to .400 lift. But what made sense in a stock head clearly doesn't when the lift increases and the port gets larger as proof from your re-work and the huge flow improvements above .200 lift. With the slow opening factory cams, they spent allot of time below .250 lift and the 30 degree seat worked. Sounds like an "old school" owner or shop worked on these first and assumed Edelbrock didn't know what they were doing with the 45 degree seat. For engines with .800 to 1" valve lift, I like playing with 50-52 degree seats. Helps on some, not on others. Your seats look nice. Serdi machine, Sunnen?

[gtofreek]

We use a Sunnen seat and guide machine, VGS-20. We also use carbide pilots for a very concentric seat. We use the Sunnen VR-7000 valve refacer, which is chuck-less, and always faces valve concentric. We also use a Sunnen DRO setting fixture for setting the cutter bits to put the seat exactly where I want it on the valve.

[GOAT WHORE]

Always appreciate your posts Paul, thanks.

[steve25]

Thanks for the post Paul!
Where these the 72 cc E heads?

[gtofreek]

Originally Posted by steve25

Thanks for the post Paul!
Where these the 72 cc E heads?

Yes they were.

[Tom Vaught]

Originally Posted by mgarblik

We can see the benefit of the 30 degree intake seat even when applied incorrectly to the E heads. The factory, with the much smaller ports, smaller throat and max lift of .407 would probably be better than a 45 degree most of the way to .400 lift. But what made sense in a stock head clearly doesn't when the lift increases and the port gets larger as proof from your re-work and the huge flow improvements above .200 lift. With the slow opening factory cams, they spent allot of time below .250 lift and the 30 degree seat worked. Sounds like an "old school" owner or shop worked on these first and assumed Edelbrock didn't know what they were doing with the 45 degree seat. For engines with .800 to 1" valve lift, I like playing with 50-52 degree seats. Helps on some, not on others. Your seats look nice. Serdi machine, Sunnen?

X2 on the "Old School Owner/Shop"

X3 on Pontiac knew what they were doing with the head and valve angles for THEIR street applications.

Tom V.

[steve25]

The owner of those heads is lucky you where able to get a 45 seat back in there after it was cut down and back to a 30!
I guess they did not max out the OD of that 30 did they?

[AC445]

Hello,I've posted this before,approx.35-40 years ago I took a broken 614 head to Jim Aller for flow testing.He checked intake angles in 5 degree incriments from 30 to 45 degrees.In this case with a port match and a 550 lift sft cam, 40 degrees worked best.So I think racers should be open to use whatever angles work best for their combination.

[gtofreek]

When using odd angles, you are stuck with using stones to do the valve job, or buying a lot of custom cutter blades.

[johnta1]

When using odd angles, you are stuck with using stones to do the valve job, or buying a lot of custom cutter blades.

True, but 40 years ago, they didn't have cutters yet?
(at least most machine shops didn't)



I can remember not being able to find stones big enough to do the Pontiac intake because most were for the SBC.
You could get some 2.19" for the BBC and regrind them to what ever size you needed.

[AC445]

Hello again,I still have a Kwik-Way 40 degree stone in the garage.Seems like a bargain for 10-12 HP.

[GRX]

Great thread. As always, your efforts sharing info and images here are much appreciated Paul. True about the odd angles. Brings back some memories of my "stone age" valve jobs. The older IH 345 with their 37.5 degree exh seat comes to mind. Always wondered about those.

[mgarblik]

I have the same Sunnen VGS20 machine and really like it . Wish it had a little more throat space for some operations like guide liners on some heads. I have the older Sunnen valve grinder and it is not centerless so I have to dial indicate every valve stem before grinding. Takes some time but does a nice job. Paul, have you tried the Joe Mondello signature cutters he developed a few years before his passing? I think they are just great for many applications and available from Goodson. A nice selection of 50 and 52 degree cutters there.