History HELP... Trying to identify Hildebrandt center bolt valve covers

I'll check on the AMC Forum and get back to you... I don't have one at home.

 

Got a quick reply -- Length and width (of AMC Gen1 327) is 21x5 3/8 and distance on holes is 9 1/2 center to center.

 

Thanks Frank. Guess that rules out AMC.

 

these fit right on a 324 head

 

I think that you got it here and the lumps are so you could run Stude adjustable rockers.

 

Catalog lists only Chev, Olds and Cad

 

That's it!! Who knew a 324 and a 303 valve cover were different? Thanks Louie

 

Olds are all the same bolt spacing.... 1949-58

10 3/8 c to c


303^




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371^


Yours are 10 1/8 or 1/4 off

And they do not match the heads..... 1 bolt installed and this is where they locate


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This is what an olds head looks like



If the cover was the correct length ....
Here is where the gasket would lie


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Here you have examples to the ones in question...,.

Bottom two stock and aftermarket 371 covers
Middle stock and aftermarket 303-324 covers

All have same radius's on the ends top and bottom.....

Top is cover in question.... As you can clearly see... Radius's are not the same and will not seal on the head


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^^ Love me some dimples!

 

Stude....you can run all four....run just the out side....or.....just the inside....

 

Tony,

I also have a set of the hildebrandt covers that are supose to be olds, my bottom flange looks the same too and bolt center to center is 10-1/8.

I have a set of cadi valve covers (50 up type with 4 outer bolts) and they are alot longer than olds, i would assume the 49 cadi has the same length valve cover as 50 and up cadi but cant say for sure, so we basically need someone to measure the length and center to center of the 49 center bolt cadi so see if thats what these fit too.

(edit read in an earlier post that the 49 cadi had a 14" center to center pattern)

 

great thread!

 

But,

One thing i have to disagree with you about Tony is the length, if you put it on one bolt like you did its going to offset it way the one way and not work, i just went out and popped the cover off of a 303 im working on at the moment and to the brand new fel pro gaskets and held them up to the covers, sure its not ideal but they will work and seal just fine, the patterns to me were just poorly made, the mounting holes will also need to be enlarged a few sizes, i took the valve cover to the 303 head that has studs in it and kinda put it over one stud and then pulled it over a little and it popped over the second stud with very little effort and when on both studs centered up just fine on the head, so when the holes are opened up a little they will slide right on.

i know the corners on the covers are cuttig it close but if you look at the material where the bumps are there really isnt any more there than on the corners

jeff

 

brought the hilde cover back out and stuck it on the 303 and marked the over hang, about 3/16 per side with a light 1/4" of sealing surface still on the ends.

Again, not ideal but would still work fine.

So to recap, they are olds, they were just poorly patterned and fit. maybe they were hoping for more shrinkage.

jeff

 

I have those same valve covers on my 371 Olds engine. Rather than slotting the holes, what I did was make up new studs with a slight offset. Loctite the threads where they go in the head so they stay in position, and you're done.

 

Good idea there too.

I have a set of repop nailhead valve covers that were made wrong and thats what i was planningon doing with them too.

jeff

 

Thanks Jeff for the clarification. A lot of guys have been telling me that they had to be Olds because Hildebrandt only made valve covers for three engines...SBC, Caddy, and Olds. And Olds was the only one with center bolt holes.

 

View attachment 2180077
View attachment 2180078


I agree with poor castings and machine work that may have happened in the day...... While you can lay an Olds gasket on and it appears all is well...... When it is centered on the head and one can see an obvious gap where the it does not even cover the head on each end..... And the the bolt pattern being that far off.... And the cover is used without any sign of abuse.... Trying to get the bolts in..... You have to wonder....

Now.... Will a cork gasket squeeze in there and seal?? Probably....
Can one get them on Olds heads and keep the oil in.... Sure...... Can you beaver the holes out or use offset studs... Of course

Will I have to work on them with a tig welder ...add some material and resurface them ..YES


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Foundryman made an incorrect shrink factor calculation.

 

The PATTERN man made an incorrect shrink factor calculation.

I bet you have an early production piece that was changed for a better fit pretty soon after Hildebrandt started getting them back in the mail.

 

Tony,

Mine fit my heads way better than yours, with no gap, so your set and mine must be a little different also.

 

dang....wrong again.....(but was hoping they were going my way for a little Studie)...