NTChrist

Hi,
I'm looking to buy new heads for my '89 TBI'd Firebird, as I'm doing a top-end rebuild.
The parts that I have lined up already are; a Weiand dual plane (old style intake bolts), a Holley DP (converting to carb, with the stock pump), swapping in an LT1 cam, K-motion valvesprings, and new roller lifters.
I'm looking to buy a set of heads off eBay.
I'm wondering if you guys think these heads will flow enough for the odd 6000 RPM pull on my 305. I posted this here, as the machine shop selling them has told me they came off of carbed F-bodies.
Any advice, experiences you can offer are appreciated.
TIA!

Sitting Bull

I took this from one of f-Bird'88's postings:

Porting 305 Heads

I ported the hell out of a pair of 305 "416" castings. I installed 1.94 and 1.60" valves and got them flow tested. The intakes came up to 225cfm@.450" (185 cfm stock). The exhausts came up to 140cfm@.500" (110to 120cfm stock). I took out about 10cc's of metal out of each port. I unshrouded the combustion chamber for the new valves too. After having the heads planned, combustion chambers were 60cc's. On the intake port, enlarge the bowl under the valve. Shorten, thin and streamline the valve guide boss. The long side port wall(common wall) needs to be straightened as much as you dare. Especially right near the guide. Raise the port roof a good 1/8"+ from intake flange to the bowl. The short side in the bowl needs to be radiused and blended into the floor. Widen the floor there and blend into the walls. Don't lower the floor, just clean it up. Gasket match the intake flange to what ever gasket your using. the port wall at the push rod can be enlarged. Don't highly polish the intake port. Just blend your stone and cutter work with 40 and 60 grit rolls. the exhaust bowl can be enlarged and blended into the runner. Blend radius the short side under the valve Shorten, trim and streamline the guideboss. Clean up and enlarge the rest of the port, consentrate on the roof and walls. Do not enlarge it bigger than your header gasket. Polish the exhaust port and combustion chamber. If you spray water with the garden hose in the port you can see where the airflow is concentrated. Those are the areas to work. These heads would rival a set of unworked vortec heads. WD-40 really helps keep the dust down while grinding.

full port 305 heads "416" or "601" castings
1.94 1.60 valves 1.255" k-motion K-700 springs 60CC's chambers


Hope that helps!

NTChrist

Interesting...
So the 416's and the 601's are basically the same head?
Thanks for the info, Sitting Bull!