Im thinking about swapping in some 416 heads in place of the 76cc heads I got now on my 350. I thinking about getting them cut to take 2.02 valves for intake and 1.6 exhaust. Is this possible? Since they will have to be cut for bigger valves, the chambers will be around 66cc I guess and ill have them milled to 62cc and then have them angle milled to 56cc. Is angle milling milling this much bad. I heard that when you angle mill the bolts for the heads and the exhaust ports on the mailfold doesn't line up correctly. Anyway with these bigger valves do you think porting is neccessary or will the flow be enough for a 350?

 

Also, would 2.05 valves fit. Thanks

 

By the time you do all that, you'll have aftermarket head $$$$$$ tied up in them.

But you'll still have .... just some junk 305 heads.

Not a good plan unless you're racing it in some sanctioned class that requires THAT CASTING NUMBER. For general enjoyment, not the way to go.

 

There could be clearance issues. 416 heads are small at 58cc. I wouldnt do it with those heads.

 

There is not enough volume in stock condition to warrant using a 2.02 intake valve. The exhaust on the other hand could go to a 1.6 with nothing more then the sweeping they do for the larger valve. Of course porting will be better though.

There is enough port volume to warrant using a 1.94 intake valve with out porting.

The CSA is not enough on the other hand to support any thing more then a hopped up work truck power band on a 350 though. This can be fixed with a few hours of grinding and measuring. If you bowl blend the ridge made by the sweeper cut and open up the proper CSA for your application it will be an incredible improvement with minimal porting time.

Full porting will be even better but not everyone wants to spend 100hours porting their heads. With the time invested you could get them to the right volume for a 2.02 valve.

Don't expect 66cc chambers either that's 11cc over stock, not going to happen.