I've just finished reflowing my 416 heads with a 1.9" intake valve ( turned down manley 1.94" race flow valve).

Stock 1.84" valve in ported intake
Lift........CFM@ 28"
.05...........29.4
.10...........57.4
.15...........88.3
.20.........122.1
.25.........152.2
.30.........172.9
.35.........188.7
.40.........201.8
.45.........213.3
.50.........217.8
.55.........220.7

Modified 1.9" valve in ported intake
Lift.........CFM@ 28"
.05...........33.0.........+3.6
.10...........65.3.........+7.9
.15...........98.2.........+9.9
.20.........129.8.........+7.7
.25.........158.5.........+6.3
.30.........181.3.........+8.4
.35.........200.4.......+11.7
.40.........217.2.......+15.4
.45.........230.0.......+16.7
.50.........227.2.........+9.4
.55.........221.4.........+0.7

Not some of the best numbers for a 416 head but it's a start. A more scientific approach would have been to port a bit then flow test it rather than my port it until it looks pretty method.

I was surprised when I first flowed the head with the 1.84" valve how much the flow numbers between .45 to .55 kept increasing but now with the 1.9" valve they head the other way.

I also removed the intake valve from the head and reinstalled it back in the head up side down to block the valve guide hole. The runner then flowed 238 CFM .

At the end of the day I have a 305 head that pulls good flow numbers right in the range of most street sized cams.

 

Kitch,

Thanks for the update. Keep them coming. You've already proven the value of our efforts, and that a well-prepped SBC stock casting can outflow Vortec heads, as well as some of the other aftermarkets, and significantly outflow the World S/R Torquer 305s:

Lift........CFM@ 28"
.05..........30.6
.10..........65.8
.15..........76.7
.20.........123.1
.30.........170.2
.40.........195.4
.50.........199.8
.55.........198.3

 

Verifies my results.....

When ya get them bolted on you'll have to tell us how they work for ya.

 

Just curious: Where did you get the #'s for the S/R 305's? Is that out-of-the box, or ported? They're not even close to what World claims.

Even so, every write-up I've seen on those heads had at least pocket port work done.