[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?

[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.