Wolfskin

Ok, so i have an 85 T/A, with the low output 305, and it sucks! I have a comp cams XE268H, and a Weiand Stealth intake that I want to swap, but now need to figure out which heads I need. I want to keep my compression ratio around 9:1 or 9.5:1, and would like to run 194/150 valves. Which heads should I look for? Or should I take the 376450 heads that I have sitting in the closet, and have them machine to fit the valves out of my 882's? This is my first 305, and the parts are from a 383 build that I've run out of money to finish. Any help is appreciated. Sorry, I haven't looked at the casting numbers on the stock heads yet. Thanks.

F-BIRD'88

Of the factory 305 heads the 416's are the best ones to port and build up.
They need porting as well as the larger valves.

The hot ticket with doing larger valves especially used ones in a 305 head is to cut the used 1.94" intake valves down to 1.90" diameter in a lathe then regrind the 45° valve face and grind in a new 1.90" valve seat on your 305 heads to accept the custom 1.90" intake valves. Now you have fresh meat on the valve seat in the head to create a good multi angle valve job on.
Get your local auto machinst to help you. (he will need the finished 1.90" valves to establish the new valve seat in the heads.)
The 1.90" valves made from a old 1.94" valve will fit the 305 heads chamber better with less chamber deshrouding and cutting it down will allow a fresh thick durable valve margin (edge) to enable cutting a new 45° valve seat + a 30° back cut. Now port the head and do the bowl work to work with this new 1.90"valve and valve seat.
As long as your used 1.94" valves, valve stems are not badly worn or bent they are usable. ( especially if you cut them down to 1.90")

The comp XE268 is a good cam but needs (more than stock) compression 9.5-10.5:1 and in a 305 it needs a high stall converter 3500stall best and a good bit of gear. 4.10's is not too much at all.

I would use a KB144 piston with a felpro 1094 head gasket and ported 416 heads.
http://www.hioutput.com/tech/343hp/343hp.html

As you can see in the dyno test of this very similar 305 build up article with a similar Lunati cam the torque curve is well up there in the rpm range. The 305 will want to rev and needs gear and converter to perform with the XE268 cam.

If you are stuck with a stock converter an gear use a smaller camshaft.

Wolfskin

Thanks. yesterday I paid the local machine shop $350 to set me up with a pair of 601's. They are gonna clean them up and do a 3 angle valve grind on them. I figure that this should be about all that I need. I'm not worried about the stall speed as my car is a 5spd. so in a week or two I'll have my heads and hopefully get this top end swapped out. I should still be around 9.5:1 and somewhere close to 300hp. I'll still be running my stock 3.27 gears, so I won't be as fast off the line as I'd be with 4.11's, but my top end should be much higher. I'm hoping for 150mph. It's sad that my beat up and broken 77 el camino is faster than my trans am, and the elky is only firing on 7 cylinders. Hope this fixes that.