91 SC Engine Build

SOLOSC91

Registered User
Hey Guys, i was going to overhaul my 3.8 oil slick, but seen some mention about a 4.2l block being a stroked version of the 3.8, i have a 98 F150 with a very healthy 4.2l and a nice Tranny i took out of a Mark VIII if itll work.

SO i have some assumptions:

i assume i could use the 4.2l Pistons, Cam?, Crank and Block and just slap my 3.8l , connecting rods, heads, intake, sensors, oil pan and of course a chip tune.

Anything Else to add? Thanks in advance.....
 
You could use all that from the F-150. But I am not sure if the cam is an improvement over what you already have. And I don't know if the splitport cam would work well with a single-port engine.

The crank, obviously, you will need. You should be able to use either block (although bear in mind that one of the main bearings in the SC block is different).

The 4.2 pistons have a somewhat smaller dish. That will increase the CR. Also, the longer stroke of the engine increases the CR a good bit. All in all, it will be much higher than a stock 3.8SC, and you may need in-depth tuning to solve the issues that creates.

The rods will depend on the pistons you use, as the piston pins are much higher on the 4.2, necessitating (or allowing) a longer rod. You can use the SC pistons and rods in the 4.2 block, BUT there may be a clearance problem with the block rails. (Shorter rods may "kick out" more and the rod bolts may tag the block.) I haven't done that swap, so check it in person or ask someone more knowledgeable than me before you combine parts.

There may be some other odds and ends you need, like timing cover, etc. I don't know.
 
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