I have a big block cast # of 3855961, suffix IVR
I know that the cast # was used 65-67 / 396 but was also used 66 / 427, I can find suffix IV 65-67 / 396 But can not locate a suffix of IVR, can any one tell me whats the difference in IV vs IVR
Thanks Michael

 

IV would be a 396, date would determine the casting date, rated at 325HP, 4B,TH transmission, installed in a non-descript passenger car. R portion would refer to Rochester 4 barrel. IVR would indicate a '66 396, 325HP, Rochester 4B with a TurboH 400 passenger car.

 

TOPLESS 68
thank you
I could not find out about the R
the heads are 3872702 dated J 28 5 & J 29 5 and were used 396/ 325 & 360 hp but also used on the 427/ 390 hp, the block is dated I 22 5 or Sept 22 1965 I KNEW I COULD NOT BE THAT LUCKEY (that it would be a 1966 / 427)
Michael k

 

The R for rochester ( makes sense ) but the intake is dated K 2 5 and is numbered 3866948 and has HOLLEY and GM 2 T cast in it also and top ports are not a bread bore??????????????????????? I AM LOST ON THIS MOTOR
I have a 68 and just wanted to know?????
just picking up extra big block