rocker valves springs and retainers

does the roller rocker conversion kits for clevo fords work on the xflow?
if not what machining do they require?
what size stem does the ford 250 use can they be amde to take an 11/32 stem with no to much drama.
can you bolt shaft mount rocker arms from a chev/ford bb or clevo ford onto a 250 engines with the pedistals removed?
what size springs does the 250 take?
are there any difference's between an exhaust and inlet valves?
as iam wanting to run bb chev exhaust valves 1.88 machined to 1.8 and 1.6 sb chev exhaust.
or do i need to machine down 2.1 inlet valves to 1.8.

thats it for moment
thanks
drift

OK i"ll answer your questions:-
does the roller rocker conversion kits for clevo fords work on the xflow?
if not what machining do they require?
Yes
what size stem does the ford 250 use can they be amde to take an 11/32 stem with no to much drama.
That is their size.
can you bolt shaft mount rocker arms from a chev/ford bb or clevo ford onto a 250 engines with the pedistals removed?
Probably
what size springs does the 250 take?
Cleveland etc
are there any difference's between an exhaust and inlet valves?
Yes size & materials.
as iam wanting to run bb chev exhaust valves 1.88 machined to 1.8 and 1.6 sb chev exhaust.
Stem size is wrong, head size is about what later heads have anyway.
or do i need to machine down 2.1 inlet valves to 1.8.
Stem size wrong again, too big, and couldnt cut a 2.1 head down to 1.8.
Look into the best head, there are plenty of posts here to help.
A7M

whould it be possible to go to 3/8 sorry had the numbers mixed up (was thinking the 11/32 were thicker stem) to try and get some more reliability.
later heads ive droped 3 in 3 years last one dystroyed the engine its getting expensive so wanting to get some mallory stainless valves for more reliabilty again.
could you use an exhaust stainless valve as an inlet or is the design behind the head to much difference and flow restricting to worry about moding.
all ready have a head its in the costic bath atm its an e2.
when using clevo conv kit for rollers ill need longer push rods as well as harder?
drift

have you thought about some exotic metals on the valves? like Ti? they would have to be custom made but about anything like that for a six is anyways. the added cost might be worth it if it will hold together.

yeah i though about ti but iam still using standerd steel so stainless should be good.

Lyonsy, what is your application first? Do you even need to play with valves?

Stock EFI engines use 1.84" inlet and 1.55" exhaust and as long as you keep the revs down around 5500 - 6000 rpm they will survive.

You can use 351 Cleveland Roller Rockers or you can just buy the Yella Terra ones that bolt straight on without modifying the pedestals. If you use the bolt on type you can have trouble with tappet cover clearance though. A spacer, custom tappet cover will sort that out. Usually the pressed steel tappet cover fit over them anyway it is just the alloy efi tappet covers which have trouble.

The 351 cleveland ones use the screw in studs and you machine the pedestals off, cut up the guide plates and mount them on individually under the screw in stud and loctite them so they don't come loose.

Valve springs you can buy direct from Crow cams to suit the 250. They have double valve springs to suit various seat pressures. You have to buy retainers and caps to suit the double springs also. You can use Crane 838 or 893 as well which work in clevo engines but you need to check your installed heights. Fomr memory my springs had a 1.87" installed height but that can change depending on what collets and retainers you buy. You need to shim the springs to get the right installed heights also.

If you are having valve made up for it the blocke doing it for you will make sure he cuts the collet groove in the right spot to give the installed height required for the springs you need. It all depends how wild your cam is going to be.

application is speedway so 5min to 30min of running at top rpm.
iam just sick of blowing engine's so iam over engineering the next one to be better.
will most likly run the standerd inlet valve with a larger 1.6 exhaust valve on a ported head.
unsure what springs may go for some uber expensive ones the nascars are using to try and retain spring life and tension for the season.
also may go roller cam but most likly just soild with some teflon coating on the lifters.

you can get stud mounted roller rockers for the clevo that will bolt right onto a 250 x flow without any machining or mods for about $350

Ahm the use of hard as teak 250 iron X-flow pushrods. The stock alloy head and Cleveland 'bundy tubes' were, as the late Brad Girdwood said, like lady Devines bum...not ment to be rubbed.

If your using stud girdles, get proper cast iron or hardended pushrods (some FE V8 sizes fit too). The stock ones in the alloy head era are trash.

Over in Moo Zealand, the 3.3 alloy versions found in manual XD/XE/XF 4 and 5 speed Falcon GL's were a bit notorious for loosing them when taken out to the 5500 rpm rev line.

yeah looking at getting them for the road car later gased
but they wont fit with what i have planed for the head as iam wanting to take the studs out to 7/16 threads so i dont pull any out.
plus i may be able to run shorter pushrods and get a higher ratio done as well like 1.8 or 1.9 off a chev.
funny thing about those bundy tubes never had a problem with them as thats what ive run for years never bent one or spat it out the the others bend and spit out all the time on other cars.
i dont know if ill girdle the bottom end yet but the main caps will all be studed all depends on what i can afford this time then in 9months when its rebuilt ill do more just wanting the basics right first.

Just get guide plates to fit 7/16 studs

These rockers are stainless steel and are chev ratio one problem with using chev rockers is that the distance from fulcrum to roller tip is longer than the ford and they sit on the edge of the valve tip, it will cause damage over time but could be reduced with the addition of lash caps giving the valve tip a larger area

These rockers are going on my 460 in my transit van the pics are just to show that theres budget roller rocker for the 250