engine parts interchangability


New Member
I have a 3.8 out of an 89 t-bird and I understand that it is the exact same engine as the 3.8 mustang 94-? is this true? and what year mustangs have this engine? Also, what internal parts are interchangable in the 4.6 to the 3.8 I think the pistons are. Set me straight here! I gots to know!


Senior Member
I dont know for sure but will try to help, the 89 3.8 is basically the same as the 94-98 and shares some simularities to the 99+. they were upgraded in 99. I dont think much from a 4.6 will fit the 3.8


Well-Known Member
The older 3.8's are very similar, but have slight differences in rod and piston measurements. But the block is basically the same.

No parts from the 4.6 rolling assembly will work in a 3.8. Total different style/ class of engine.


New Member
The heads changed in 96, went with a smaller stem valve with a conical spring, thats where their 5 hp came from I hear.


New Member
your main source of parts interchange will be 5.0 style stuff
(valve train) and 351 W and Cleveland rods, etc. Pistons
are 3.81" standard bore, unique to the 90* V6 family.