Hi everyone, I was wondering what camshaft was originally in a '70 Olds Rallye 350? My mechanic says I need a new camshaft, but didn't know if it was a hi-performance cam in them or a standard Cutlass cam. Any help on which one I need & where to get one would help. Also he said I need two lifters. Can I get just two or would I need to order the whole set? Thanks for the help ahead of time.

 

Someone else might be able to answer the first question but ...........

if you are replacing the camshaft you need to replace all of the lifters and I would really have to wonder about any "mechanic" that would tell you otherwise.

I think that a Melling ROC10 would be the right cam but not 100% sure, It replaces GM 402194

 

I'm sorry I must have worded that wrong. He just told me that two lifters were bad. I was the one that thought I could get away with just replacing the two that were bad. Sorry for the mix up.

 

Your machine shop should be able to get the cam for you along with the lifters. Ill try to verify the part number later on.

 

Ok, Thanks. Would it be the same cam as a Cutlass?

 

The only engine offered in the Rallye 350 was the RPO L74 350 4bbl engine with 310 gross HP. This was the standard equipment engine in every Cutlass Supreme built that year. Manual trans cars got cam P/N 393859 with 286/286 duration, 598 deg overlap and .472/.472 lift. AT cars got cam P/N 400084 with 250/264 deg duration, 36 deg overlap, and .400/.400 lift.

 

Thank You for the info.

 

402194 was the W31 cam, 308 deg, .474" lift and would be a high performance type cam, unlike the moderate/smooth running cam that came in regular 350s with low number rears (like 3.08, 3.23) with standard torque converters, etc.

 

Where can I buy this cam? It seems everyone I look at online does not meet the specs listed. I am looking for OEM specs., not high perf. Thanks

 

Do you need to have an exact blueprint of the OEM cam? There are lots of aftermarket mild smooth-idle cams available with similar characteristics to the original and possibly better performance due to taking advantage of the design improvements of the last 55 years.

 

@cutlassefi

Here, this guy may be able to help. He's an engine builder and CO'S resident camshaft guru. If he doesn't chime in on this thread send him a PM and tell him what you're looking for.

Also, keep in mind that the duration figures you're seeing are probably rated @0.050 lift rather than the original factory gross figures.

 

I'm just looking to get one that can be put right back in w/o making any other alterations (except the new lifters).

 

Thankyou @BangScreech4-4-2 i will look into him if I can't find what I'm looking for.

 

This is our cam, unfortunately it states out of stock.



Manufacturers Description: American Muscle, Near duplicate of the Olds 310HP/350 cam (GM #400084.)

https://www.competitionproducts.com/.../HRC517771-09/

 

When you run the part number followed by the word cam online there are multiple hits including Summit Racing.

https://www.summitracing.com/parts/H...XU37hU8IuvHQit

https://monsterengineparts.com/produ...160-517771-09/

 

Apparently the ROC 10 is not available anyway. I can check a few other sources Monday AM The problem with anything much more than stock is that you will be looking at a valve spring change also. Ill go by the specs that Joe posted. Is your car an automatic ?

 

Already ordered one from the link that @69CSHC posted. Cam & Lifter set. Yes, it is stock, & yes, it is automatic.

 

Sounds good ! Howards cams are very good.

 

Glad to hear that. Thank You all for the help & advice.

 

My mechanic just looked at the cam & lifters & said the lifters are about 1/8" too tall. This came as a package deal with the cam. He said the cam looks like it'll work, but the lobes are not as "pronounced". I assume I'll have to return the lifters, but will the cam work with the lobes not as "pronounced"?

 

I hope your mechanic is just joking with you.... Otherwise he might be the joke.

 

No, he doesn't joke. He said he measured them & placed them next to a good one he pulled from the car & he said you can visibly see the difference in the height.
I trust this mechanic. He has never steered me wrong before & I have been using him for probably about 6 - 7 years.
Everything I have taken to him he has fixed correctly.

 

He needs to compare the pushrod seat height to the old lifters. The total height of the new lifters might be more but as long as the pushrod hgt is the same it wont matter. Tell him to stand a new and old lifter up on a table and then put a pushrod in each one. If the tops of the pushrods are at the same hgt then they will work fine. Also tell him to look at the oil band and oil hole in the two lifters and compare them. It is very common for new lifters to not be identical to 50 year old ones.

You can call Howards and verify with them also. They have very good phone support.

 

Ok, Thank You. I will give him the information & see what he comes up with. If for some reason it doesn't work out I will call Howards

 

If you can do it I would get your mechanic to call Howard's just so nothing gets lost in translation.

 

Very good idea

 

If he can really tell what the profile is just by looking at it, then he needs to work for Comp, or Howard’s or whoever. Looks can be deceiving.

 

There is a lot of negative remarks on this. I just want to make sure that these are the correct lifters for my car. He is just telling me what he sees. I went over & he showed me the difference in the height, and I can see that it is about 1/8" taller than the ones he pulled from the car. He is just looking out for me & doesn't want to do anything that would lead to more problems down the road.
There is a way to help on this site w/o being so rude about someone you don't even know.

 

The way you describe a camshaft is by the cam card not by using words such as "pronounced", "big" or "large lift". I don't think anyone is trying to be negative but just trying to caution you that not all engine machinists are created equal.
Attention to detail is key, which your guy seems to have and if your happy with him that's all that matters.

 

Those word "Pronounced", "big" & "large lift" were probably him trying to use words that he thought I would understand. I am by no means an "engine guy". If he used the "proper" language I would probably look at him like he had 3 heads.

 

Regardless, if he's your guy, get him on the phone with the Howard's tech to explain his concerns.

 

most replacement lifters have a much shallower cup where the pushrod sits in the lifter which is why the pushrod will sit higher…like the 1/8” he’s seeing.


because the Olds doesn’t have adjustable rocker arms, he has to make sure the lifter cup/plunger isn’t compressed to deep into the lifter body when using replacement lifters or the lifter may not function properly.

do each cyl individually when on the firing position. When tightening down the rocker arm bolts, while rotating the pushrod back and forth with your fingers, , you want to have another 1/2 to 3/4 of a turn of the bolt, after the pushrod clearance is taken up, before the bolt/ rocker bridge contacts the head.

if there is more than 3/4 of a turn, you’ll need shim under the rocker bridge bolt to reduce the lifter plunger/cup depression. there are shims to do this

show him this message, he’ll understand

shim kit

 

Should also make sure the oil band on the new lifters is in the same position as the originals..put them side by side to compare ..although Chevy style lifters can work with very mild big base circle stock cams without problems

 

Hi everyone, the cam & lifters are in & everything seems fine. When we measured the old lifters to the new ones they were fine. We must have just grabbed the bad one & it was worn away that much (about 1/8" to 1/16"). Thank you all for the great response.