Ok how come everyone uses Chevy valves in the 300 head when I am pretty sure that some company(maybe even Ford) makes actual performance valves for the 300? Are the Chevy valves cheaper, or just better for some reason?

 

Readily made to fit if going to larger valves...and the cost is not outrageous.

 

So the Chevy valves already fit? Or the other 300 valves? Also who makes the 300 valves.

 

The chevy valves do not fit. People use them because they are cheaper. a machinist has to cut them into your head


You can still get stock valves.

 

Who makes the performance valves for the 300, or Ford valves that work easily? I know someone does make them, but I can't remember who.

 

Chevy valves nothing new. They were also used to increase valve sizes in 289s back in the day. Cheap, available. Ford doesn't make performance parts for the 300.

I searched some cam makers and other performance sites. I found valves for other engines, but not the 300.

 

SI valves is the only company I know of who makes the larger valves for our 300's. They have a great site, and the larger valves can be found in one of the performance sections. I remember it took me a while to find them on their site, but they are there.

Something to consider: I believe it was around 85 that Ford changed the size of the valves. SI valves has both the old and new style. But be sure to check the casting #'s on your head to make sure you get the correct length.

Yes, of course the sbc valves are less exensive than the Ford valves, like everything else sbc. However, they are, iirc, about .095 longer, and require sbc keepers and retainers and springs. They have to be set up with the proper psi for your head. They also require longer push rods. Crane cams makes 5/16 pushrods that are, iirc again, about .065 longer than oem, and work well with the sbc valves.

My engine has the sbc valves, and I have 2+ years on the engine. Had I gone with SI valves, it would have saved me a lot of time and $.

I never drove a 300 with a stock engine, so therefore have nothing to compare it to. I will say, however, that it is faster now, with the oversize valves, head work, and other mods, than it was with a 390 with a 2v carb and points.

 

I found some on that SI Valves Website. They are in the Portflow and Quickflow section. They are 1.94 intake and 1.60 exhaust. I think that is in the size range most people want. Thanks F-250 are you still making the intake heaters? When I get my tax return I intend to buy one.

 

I'm just making one or two per week, so sure, I'm be here. Thanks. Just PM me and we'll get it rolling when you're ready.

 

I just wanted to post the price of the over-size SI valves: $12.50 each, whether intake or exhaust. That means $150 for six intakes and six exhaust valves. And that price is for the early length (pre '86) of 4.810".

The late models, '86 or newer, are 4.750".