Originally Posted By 70gtx440dana
Originally Posted By Morty426
There are no 440 sixpack blocks, just 440 blocks.

A sixpack engine is typically marked HP2

Casting dates can be all over the place.



HP2 designation as "typical" for 6 pack engines is a myth as far as I am aware........HP designates an HP engine assembled on first shift....HP2 indicates second shift assembly. I can think of no valid reason to only assemble 6 pack engines on 2nd shift. I assume these engines were assembled throughout the work day regardless of 4 barrel or 6 pack configuration. However, I may be proven wrong. It would not be the first time.

For the OP.....accepted date range for exhaust manifolds is several months to just a few days prior to the vehicle SPD. I don't think you will correlate it very well to block casting dates as they do not seem to align with SPD's.



Correct, I have three ‘70 F440 HP blocks that all happen to be out of real V -code cars. One from a ‘70 RR Lynch Rd, one from a ‘70 cuda Hamtramck (my cars numbers block) and one from a ‘70 Super Bee Lynch Rd. All are HP and not HP2.

The “six pack”/HD rods were used in all ‘70-1 440-4 HP and 6bbl engines. The only differences were the valve relief pistons and 3-bolt cams being used in the multicarb versions. Both the 4 and 6 bbl rotating assemblies were externally balanced.