Bigger valves for 12v

BlackStroker

BlackStroker

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Mar 28, 2007
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This may have been discussed before but...I know running bigger valves in the 12v will improve flow with a corresponding well done port and polish job. So where are you guys getting the bigger valves, and what are the specs. I'm looking for part numbers or vendors that would sell these valves. I know you can get them from Haisley, just looking for other options. Thanks.
 
when i searched all i found was that they were just using intake valves all the way across.
 
I bought 12 intake valves from Snedge on here. That is what I have seen a few on here do. They are getting coated as we speak..
 
If i can't get any more info, the intakes are what I'm going to run. I was just thinking of going bigger.
 
Right, but there seems to be a lot of talk about bigger valves, just no specific information. How much bigger can you go before shrouding becomes an issue? I say run as big as will fit in the cylinder bore...i dunno just asking to learn.
 
Stepping up bigger for next year huh? Will you have it ready by the test and tune day? We have three more p pumped 24v's converted for this year. Should be some good competitive trucks coming from central IL. Especially if you get your going again.
 
working on set right now, two diffrent sizes. just have to wait to get to that project next.
 
The inconel valves I got from Haisleys were very large. I think the smallest inconel valve was much larger than the biggest stock valve. Had to have alot of machine work done for them to fit. Only a hairs width between the intake and exhaust when they were done. Then had to have the pockets machined for bigger valve springs.
 
2Tone12V said:
The inconel valves I got from Haisleys were very large. I think the smallest inconel valve was much larger than the biggest stock valve. Had to have alot of machine work done for them to fit. Only a hairs width between the intake and exhaust when they were done. Then had to have the pockets machined for bigger valve springs.
Click to expand...

Valves I'll go with but machining the pocket for a different spring.....now were talking.

Jim
 
Jim Fulmer said:
Valves I'll go with but machining the pocket for a different spring.....now were talking.

Jim
Click to expand...

Those springs are what actually led me to the valve. I wanted to get by on some cheaper valves. But the seat pressure was like 280lbs. So had to put the big boys in that could handle it. I also learned that your standard spring compressor can't be used to install them. Something with a 2-3 cheater pipe on it and another person holding the head down and installing the retainers and locks was needed.:rockwoot:
 
I researched the Ford 351W GT40 intake and exhaust valves and they will work, but the guides need reamed for the new 11/32 size. The spring pockets will work, and one can then step up to really good aftermarket springs rather than the old standby #60s

You will need lash caps to make up the slight difference in valve stem length

As stated at this size you are shrouding the valves really bad, so the gains may not be that great

If memory serves from my mock up I beleive you can get away with 1.84 intake and 1.75 exhaust for sure, and with some really good machine work maybe a little larger

I thought i read on a shop site "like" schieds that one head got done with a Ford 2.02 intake and a 1.78 exhaust without hitting anything but the shrouding was terrible

because of the cost of machine work i went with Cummins intakes all across with a 45 degree angle, as it was easy and cheap

One of the screw type spring compressors will make short work of any spring pressure up to about 900 lbs - not that the cummins flat tappet and cam could withstand that pressure. I beleive I read somewhere that the maximum spring pressure without wiping out the cam is low 300's so thats a cakewalk to install
 
Last edited:
seeker1056 said:
I researched the Ford 351W GT40 intake and exhaust valves and they will work, but the guides need reamed for the new 11/32 size. The spring pockets will work, and one can then step up to really good aftermarket springs rather than the old standby #60s

You will need lash caps to make up the slight difference in valve stem length

As stated at this size you are shrouding the valves really bad, so the gains may not be that great

If memory serves from my mock up I beleive you can get away with 1.84 intake and 1.75 exhaust for sure, and with some really good machine work maybe a little larger

I thought i read on a shop site "like" schieds that one head got done with a Ford 2.02 intake and a 1.78 exhaust without hitting anything but the shrouding was terrible

because of the cost of machine work i went with Cummins intakes all across with a 45 degree angle, as it was easy and cheap

One of the screw type spring compressors will make short work of any spring pressure up to about 900 lbs - not that the cummins flat tappet and cam could withstand that pressure. I beleive I read somewhere that the maximum spring pressure without wiping out the cam is low 300's so thats a cakewalk to install
Click to expand...

:hehe::bang
 
Anthony, is it your goal to look like a complete ass in every thread you care to comment, and also to make each and every single member here dislike you? If it is, I strongly feel you are right on track.
 
We use a 1.97in and a 1.87ex all inconell and 11/32 stem an our bore is a little bigger than stock .:rockwoot:
 
Im not sure where i read this but i thought that stock cummins exh valves were inconel? and intakes are steel? If so how well are the intake valves holding up as exhaust valves?
 
I've seen that most that use the intake valve across the head have them coated to help handle the heat. Protection is always a bonus.
 
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