Chevy valves instead of Ford ones!

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Robbie1962
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Chevy valves instead of Ford ones!

Post #1 by Robbie1962 » Wed Nov 07, 2018 4:04 am

Hello everybody,

need some good advice. Overhauling my 300cui make 1983 I bought a complete performance set at Cliffords. The problem occurs with the Chevy valves which are 0.100 longer than the Ford stock ones what is resulting in a wrong rocker geometry and ofcourse lenght of the pushrods. Cutting off the valves by 0.100 as I was adviced is no option since the rocker arm will hit the springwasher and springkeepers will be too near to the cutoff end. The head is already mounted so I was thinking of lifting 0.100 the rockerarm by using other or cutomized rocker studs and customized pushrods. Are these rocker studs bolt in to the head or are they pressed in? Or are there any other options for example by mounting other rocker arms, roller rockers or whatever? Any advice is very welcome, best regards Robert

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THE FRENCHTOWN FLYER
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Re: Chevy valves instead of Ford ones!

Post #2 by THE FRENCHTOWN FLYER » Wed Nov 07, 2018 8:59 am

I use Chevy valves all the time The extra .1" is no big deal. If you do the math you'll see the rocker arm pivot only needs to be raised about .040" to restore the correct geometry of the rocker arm.I think the '83 head had pressed in studs. My advice would be to install screw-in studs with a 3/8" post and use an adjusting lock nut to properly position the rocker. You may require .050" longer pushrods - maybe not, depending on the tolerance stack-up (milled head, decked block, etc.)
Likewise, if your head has screw-down stamped rockers like the '85 - '86 you can shim them up .040" and adjust pushrod length as necessary. Hope this helps.

Also, be sure you still have enough installed spring pressure and that the extra length of the valve did not add extra length to the installed height. Spring shims may be necessary too. None of this is rocket science, it just requires thorough consideration of all the factors involved.
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old28racer
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Re: Chevy valves instead of Ford ones!

Post #3 by old28racer » Wed Nov 07, 2018 9:28 pm

I just got done installing a set of Chevy 1.84 / 1.60 .100 long valves in a 300 I am building in my shop. 1994 engine block decked .022" with 240 68cc head that was milled only .007" to clean it up. The head stud boses were milled .075". drilled & taped for 7/16 BBC screw in stids. I am running steel BBC 1.7 roller rockers. After getting everything were it should be I measured the new push rods to be 10.045". I was able to order Smith Bros hardened chrome molly 5/16" with .080" wall as a shelf item in 10.050" at $7.89 each. There are lots of push rod companys out there, I used Smith Bros in my dragster for 30-35 years and had real good lock with them.
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Re: Chevy valves instead of Ford ones!

Post #4 by Max_Effort » Thu Nov 08, 2018 10:01 am

The previous responses on how to compensate for the longer valve are right on...

I just will add that.... dont cut (stem grind) the valve tips .100"
That will remove most all, if not all of the hard tip and the valve will wear very quickly.

(I know the OP isn't going that way, just saying).

I substitue different makes of valves in different heads, not uncommon at all.

Getting a extra .100" opens up more spring choices and lets you run more lift, use spring cups or locators.

Robbie1962
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Re: Chevy valves instead of Ford ones!

Post #5 by Robbie1962 » Thu Nov 08, 2018 11:40 am

THE FRENCHTOWN FLYER wrote:I use Chevy valves all the time The extra .1" is no big deal. If you do the math you'll see the rocker arm pivot only needs to be raised about .040" to restore the correct geometry of the rocker arm.I think the '83 head had pressed in studs. My advice would be to install screw-in studs with a 3/8" post and use an adjusting lock nut to properly position the rocker. You may require .050" longer pushrods - maybe not, depending on the tolerance stack-up (milled head, decked block, etc.)
Likewise, if your head has screw-down stamped rockers like the '85 - '86 you can shim them up .040" and adjust pushrod length as necessary. Hope this helps.

Also, be sure you still have enough installed spring pressure and that the extra length of the valve did not add extra length to the installed height. Spring shims may be necessary too. None of this is rocket science, it just requires thorough consideration of all the factors involved.

Thank you all for responding, if I understand well my math is wrong by lifting the rockerarm .1"? Why Chevy valves? Is there a reason for? Guess this all wasn't necesary if the stock hight was sent. Does the picture give you more solution?
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Robbie1962
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Re: Chevy valves instead of Ford ones!

Post #6 by Robbie1962 » Thu Nov 08, 2018 11:53 am

old28racer wrote:I just got done installing a set of Chevy 1.84 / 1.60 .100 long valves in a 300 I am building in my shop. 1994 engine block decked .022" with 240 68cc head that was milled only .007" to clean it up. The head stud boses were milled .075". drilled & taped for 7/16 BBC screw in stids. I am running steel BBC 1.7 roller rockers. After getting everything were it should be I measured the new push rods to be 10.045". I was able to order Smith Bros hardened chrome molly 5/16" with .080" wall as a shelf item in 10.050" at $7.89 each. There are lots of push rod companys out there, I used Smith Bros in my dragster for 30-35 years and had real good lock with them.

Allready did contact Smith Bros for pushrods, adjustable ones as in my Harley but was no option, not strong enough. I think the head needs to be taken off again to do all this and was thinking to use 3/8 pushrods with 5/16 ball ends. Just need al little customize the pushrod holes in the head.

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Re: Chevy valves instead of Ford ones!

Post #7 by Fordman75 » Thu Nov 08, 2018 6:31 pm

Get an adjustable length pushrod ( push rod length checking tool ) . Use this to determine what length push rods you need. Then order custom length push rods.
Ted

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Re: Chevy valves instead of Ford ones!

Post #8 by Harte3 » Thu Nov 08, 2018 7:00 pm

Why Chevy valves?

Because they readily work for some simple performance upgrades. All parts are not necessarily exclusive to a particular automaker. Many components the various automakers use come out of the same hole in the ground, so to speak.
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Re: Chevy valves instead of Ford ones!

Post #9 by THE FRENCHTOWN FLYER » Thu Nov 08, 2018 9:57 pm

Often Chevy guys upgrade their SBC heads from 1.94 to 2.02s. If you ask around at some shops they often have lots of 1.94 "take outs" that can be had for a song. Even some that have wear can be cut down to 1.900 and reground with no loss of flow on the 300.
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old28racer
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Re: Chevy valves instead of Ford ones!

Post #10 by old28racer » Sun Nov 11, 2018 8:10 pm

I am not a fan of two pc push rods. Unless you are building a race or turbo motor with lots of spring pressure 3/8" one pc rods are over kill. 5/16" one pc heat treated chrome moly are plenty strong enough for most all street motors and will work with guide plates. 4-5 good push rod companys out there. You need to run heat treated chrome moly push rods with guide plates & 240 68cc heads with square guide holes in the head.
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