2006-12-30 14:24:52 · 6 answers · asked by MZ 1 in Cars & Transportation ➔ Car Makes ➔ Pontiac
externally the blocks will be the same size. check all the codes out. see the below links
http://www.pontiacstreetperformance.com/psp/blockID.html
http://www.gtoalley.com/engcodens.html
2006-12-31 15:05:04 · answer #1 · answered by turkey 6 · 0⤊ 0⤋
Yes the Block Code on the front right of the block (passenger side Front) 2 Letters for most 389 and 421's
On the block just below the right head ...
If you know what year I have 85% of each list...
Example
65 389 256hp Manual trans WA WB
65 389 256hp Auto trans ... YA YB
65 389 333hp Manual Trans WE
65 389 325hp Auto Trans ... YE YF
65 389 RA 360hp Manual WS ... Auto YR
65 421 338hp Manual WG ... Auto YH
65 421 376hp 3X2 manual WJ ...auto YK
There are so many.... But easy to find...
Head codes are the same for both 389 and 421 for 64 65 66
just different combs for each... But you most likely won't find a 64 543796 or 65 #75 on a 421 block
2006-12-30 23:36:31 · answer #2 · answered by Spinner...428 6 · 0⤊ 0⤋
389
For 1959 the V8's stroke was increased to 3.75 in (95.3 mm), raising displacement to 389 in³ (6.4 L). The 389 would remain the standard Pontiac V8 engine through 1966, offered in a bewildering variety of outputs ranging from 215 hp to 360 hp (160 to 269 kW). The 389 was the standard engine for the Pontiac GTO through 1966.
421
421 in³ (6.9 L) 421. The 421 in³ (6.9 L) was bored to 4.09 in (103.9 mm) and stroked to 4.00 in (101.6 mm), and also featured larger, 3.25 in (83 mm) main journals. Unlike previous enlargements of this engine, it did not replace the 389. Modified Super Duty versions of this engine were extensively used in NASCAR stock car racing and drag racing competition. The 421 also marked the end of the option for a forged steel crankshaft. The later produced 400, 350, and 455 engines, featured an Armasteel crankshaft, the standard crankshaft of the entire Pontiac V-8 line since introduction. "Armasteel" was no more than a fancy name for a hardened cast iron unit.
2006-12-30 22:58:44 · answer #3 · answered by vinny_the_hack 5 · 0⤊ 0⤋
Well it's easy if the two are apart because it's all in the CRANK..the 389 in 3" journal, 421 is 3.25" journal.
2006-12-31 01:58:53 · answer #4 · answered by gretsch16pc 6 · 0⤊ 0⤋
you would have to go by the numbers on the block as they are the same engine block.
2006-12-30 22:29:16 · answer #5 · answered by mister ss 7 · 0⤊ 0⤋
tehres no difference
2006-12-30 22:28:48 · answer #6 · answered by Anonymous · 1⤊ 1⤋