LA, B/RB lifter support versus other engines

[Kern Dog]

Looking at the lifter valleys of V8 engines, there is some design differences between the different manufacturers. Our Mopar engines seemed to have more than adequate support around the lifter bores. Have you seen a Pontiac ?

What kind of crap is this ?

This is a 66 389.

It just seems ripe for failure, like a big cam with stiff Springs would cause those unsupported lifter bores to crack and break off.
I guess oil drain back is great!

 

[RustyRatRod]

Looking at the lifter valleys of V8 engines, there is some design differences between the different manufacturers. Our Mopar engines seemed to have more than adequate support around d the lifter bores. Have you seen a Pontiac ?

View attachment 1716460662

What kind of crap is this ?

View attachment 1716460661

This is a 66 389.

View attachment 1716460660It just seems ripe for failure, like a big cam with stiff Siri gs would cause those unsupported lifter bores to crack and break off.

Yeah, that's how they are.......I've seen a lot of them too and never a broken one. Can't be too strong. Then again, there's very little stress there.

 

[Kern Dog]

Compare the Pontiac to our 440….

Plenty of metal around the bores. The LA is even better.

 

[JDMopar]

The casting flash would bug me more than the bores. I had a 69 Firebird with a 400 Ram Air III that I wrung the guts out of every time the key turned. It never protested once as long as I owned it, motor wise. I did break a throttle cable once. Took the strings out of my shoes and tied them together, ran thru a hole in the firewall and pulled with my right hand to give it gas. Kind of hard to do with a 4 speed....lol.

 

[RustyRatRod]

So what's the 389 in?

 

[volaredon]

Yeah I was thinking the same thing about casting flash.

 

[Kern Dog]

So what's the 389 in?

It was on an engine stand at my Machinist's house. A customer of his has a GTO.

 

[65 Cuda 340]

Looking at the lifter valleys of V8 engines, there is some design differences between the different manufacturers. Our Mopar engines seemed to have more than adequate support around the lifter bores. Have you seen a Pontiac ?

View attachment 1716460662

What kind of crap is this ?

View attachment 1716460661

This is a 66 389.

View attachment 1716460660It just seems ripe for failure, like a big cam with stiff Springs would cause those unsupported lifter bores to crack and break off.
I guess oil drain back is great!

55-56 Packard V8 lifter bores look very similar to Pontiac.

 

[66Valiant528]

I can't say Ive heard of that lifter area being a problem on a Pontiac. Now the rods.....that's different

 

[Bewy]

Yes, Pontiacs have been known to break l/bores. There are three on the pass side at risk [ unsupported]. It only happens with roller cams when the 050 durations get into the 260s or more. The base circle gets reduced, so more of the lifter hangs out the bottom of the bore as leverage to break the bore. There are companies that make a l/bore brace for them.