Was it just the 69 single bolt type that was low taper or all 69-71s? I have a 3 bolt 6 pack cam from 1970, wondering what lifters I should use. Or use the core and get it reground.

I'm pretty sure all the street hemi and race hemi cams where low taper also, not sure about the six pack cams in 1970/1971

What are you going to do about the lifters ?

Well if its low taper Im out of luck...Maybe have it reground.

Iirr the 69 was just a regular 440 with the 6 barrel intake and carbs. 70 was when all the internal changes came.

I'm not sure how much angle on the lifter bottoms there are between stock and low taper
Not sure how to measure them either
i have had several sets of the early (Pre 1968) Mopar solid Hemi lifters reconditioned by a company in Seatle, WA
Maybe you can have yours done too locally

I think the low taper was a 21” radius while the standard was 18”. But it’s been a long time.

Here is the '69 TSB. Note the comments for the camshaft and the tappets.

What's the reason for low taper design?

Okay, I am going from memory so take this all with a bag of salt. The standard 440 valve gear was good for about 5800 rpm. Chrysler wanted to raise this to about 6200 rpm. So they installed heavier springs on the Six-Pack motors. Heavier spring...more cam load....a low taper lobe provides more contact area and maintains engine durability with the higher loading. Again, I'm going from memory and I only have two functioning brain cells left.

That’s really interesting. Two things come to mind..
1) By what criteria were the crankshafts “selected”?
2) Magnafluxing rods…did they scrap those that failed, or were they used in 440-4 motors?

Not to get off topic here…

If yours are gone, mine are too. It was also the rationale for the HD rocker arms which Direct Connection later claimed they'd reinforced the wrong end, FWTW.

From this thread I assume low taper lifters are made of unobtainium? Which would make an NOS 6 pack camshaft a paper weight?

Correct. And made of the standard material. I believe they had a slightly unique oil band for some reason, and I think a better retaining ring. I have some, I’ll post a pic when I find them.

I purchased an A12 new in 69, my good friend was the salesman for a MOPAR dealer in Ohio.
He specialized in Hi-Po stuff then as it was a moneymaker for him and the dealer.

I remember reading the notice posted above from Chrysler when it was published, but some of the other mods others have posted are not in my memory.
Not saying they couldn't be true, but........

Joe

PS, I just turned 80 last month so I'm among the old fart gang LOL

Joe, hurry up and get a pad and pencil out, start writing stuff down before you forget, or the cobwebs take control like they have of me !

Back in around 1978 I bought everything I could for a 1970-71 440 Six Pack. I owned two A12 69 Runners then and nothing was available for that motor around that time. I got this for a 1970 motor from the Dealership I use to spend most of my paycheck at. Crank, Rods, Piston, Rockers, Cam Shaft lifters, timing chain and lots of small parts. Bearings I bought at the local speed shop. I also bought rocker shafts but do not remember is they were Six Pack specific from the dealer. All this was still available at the Dealer. Built the motor myself and decided to sell it to a guy that had a 1970 440-6 Cuda. He finally only wanted the short block. I took the intake carbs, cam lifters, rockers, heads and valve cover off the motor and still have all that. I always thought the Six Pack Lifters were still available in places maybe not the dealership. I guess I have a lot of Scrap metal the way people have posted but I will like build another motor and put it in my Challenger Convertible.

i think any wedge that came with street hemi valve springs used the low taper lobe. the street hemi spring was a high rate spring and significantly stiffer than a hipo wedge spring. i believe all this is 6pak specific.

I've never seen any reference that stock B or RB engines in any configuration used a Hemi valve spring.

I use to race in NHRA stock classes, the first year we won our class(A/SA) at the Winternationals we had to remove one the cylinder head to allow the tech guys to measure the CC and valve spring pressures on the bench. The next year they allow any valve springs you wanted to use as long as your valves didn't open any more than their specs for your motor
The stock 1968 and 1970 street hemi valve springs had right at 125 lbs. on the seats and 325 Lbs. open at .484 valve opening on the intakes and I think right at .446 on the exhaust valves, maybe a tiny bit more or less.

Flat faced lifters.. goes against saying lifters have to have a crown don’t it.