Here are the flow numbers for my 416 heads. Both intake and exhaust have been ported. Intake runner cced in at 178.6cc and exhaust 65cc The heads were flowed with a stock 1.84 intake valve and a Manley 1.5 exhaust valve. The intake had a radiused entry in place and the exhaust was straight out of the port. The flow bench was fitted with a 3.8" bore diameter adaptor only because it was the closest size avaliable. Lift Intake Exhaust both @ 28" .05 29.4 24.6 .10 57.4 48.3 .15 88.3 75.0 .20 122.1 100.2 .25 152.2 113.9 .30 172.9 128.7 .35 188.7 139.4 .40 201.8 147.3 .45 213.3 152.2 .50 217.8 159.2 .55 220.7 161.2 A lot of metal had to be removed to acheive a 178.6cc runner the roof of the port was graduly raised from the stock port opening position to the start of the long side radius. Inside the port the size increased from 1.365" to 1.512" measred between the highest point of the short turn radius and the roof of the port. I'm sure the shape and of the stock 1.84 intake limited low lift flow as well as the size limiting overall flow. The next step will be to increase the intake valve size. I'm concerned with the limitations of 305's small chamber size, I'm not sure if I should install 1.94 valves or have them turned down to 1.90 for increased chamber wall clearance? If the heads were going on a 4" bore unshrouding the chamber would be an option with the 1.94 valve. The smaller 3.75" bore doesn't leave much room to move.

Kitch,

Welcome Aboard!

Thank you for posting the head flow numbers. That data should help with those deciding whether to port stock heads or replace them.

Incidentally, I have ported those same heads, with similar results. I installed 1.94 intakes and unshrouded the perimeter area of the intake in the chamber. Final chamber volume increased for 57 to 58cc, runner volumes averaged 177/64cc, port dimensions at the flange were 1.162" x 1.962 intake, 1.312" x 1.305" exhaust. The intake runners were raise quite a bit, as you describe on your heads. I made guide templates that fit the runners. You can print and scale the graphic and check how closely yours match (or mine match yours). I'm curious if we opened the same area and contoured similarly. Unfortunately, I didn't flow test mine.

Vader,
Here's my intake with your template in it.

Here's another runner.
Sorry about the size of the photo's, got to figure this one out.

And here folks, we have an EASIER to view photo.

And the second.

Well, you obviously went wider around the push rod area than I did. My heads are probably not flowing as well as yours at mid- and higher-lift ranges. Looks like you went with new pressed in guides, too. Bronze?

Have any pics of the bowl areas?

Always good to see pictures with flow benched backed results!

Vader,
My intake ports measure 1.175" x 2.005" and the exhaust went 1.330" x 1.370".
I haven't had new guides installed yet I'll do that when I have them machined for larger valves. The owner of the machine shop said they could fit the bronze guides after I had done my porting and while I've left them a little of meat to work with I hope its enough.
I have enlarged the top of the pushrod pinch area and it tapers down to the floor of the runner. Not that larger is always better but I can pass the end of a 3/4" ring spanner right down the roof of the runner but it wont fit down the floor of the runner
Not that these measurements truly represent the taper but if you measure in 5/8" the top of the runner measures 1.050" and at the floor it measures 1.005".
I have also increased the natural bias of the outer wall where it makes its turn into the bowl, I'm sure this is where the port picks up higher lift flow ( yes I know the numbers aren't huge but they probably aren't too bad for a 1.84 valve.) This area does run close to the head bolt hole but luckly I didn't break into it.

AJ_92RS,
Thanks for fixing the photos!

AllGoNoShow,
Yes I do have more photos but I want to figure out this size problem first.

Here's an exhaust port.