255 and 302 part interchanges?

[breidhaupt]

i have a 255 v-8 from a ford t-bird coupled to a c-6 and a 31 spline 9 in. with 4.10s. but a 130hp and 210 ft-lbs doesnt cut it. i know the 255 is a debored 302 but shares the same crank and rods. but can the heads be interchanged with a little boring or with they fit right on? and will i need a special head gasket set?

 

[Mac]

I really wouldn't even bother with the 255. Even free does not mean cheap for the end results. As far as the head gaskets, do a comparison check on part numbers between the 255 and the 302 at any parts store on line. That C-6 takes about 20 hp more than a C-4 and that 9" rear eats a lot of hp also over a 8" or 8.8
Don't know where you're headed with this project but I'd at least start with a 302.
Dave

 

[originalnitro]

Bore it to 4.000 it will be a 302, no special head basket is needed.
With your heavy truck I would look into a 351w.

 

[breidhaupt]

well everything is installed in the truck already. i got the truck from my uncle and he swapped the 390 out of it because the rod was in the side of the block and another went through the oil pan due to my cousin hot rodding it. so im stuck with what i got. i just want a little more power from it. the only performance its got going for it is headers and a dual exhaust.

 

[breidhaupt]

boring it to 4.000 is out of the question with a stock 3.680 bore. the cylinder walls were thinned on these engines to save weight.

 

[breidhaupt]

i was thinking of a 0.030 over bore but the only pistons i can find are oe compression flat tops. my only alternative to raise compression is shaving the heads and thinner compressed copper head gaskets. i was also thinking of stoking it with 5.400 rods and crankshaft. but with the full out bore and stroke i would only displace 278 c.i.d. or 4.6l. i wouldnt think that the bigger valves from a aftermarket head would clear the cylinder bore.

 

[originalnitro]

I would look for a late model 5.0 and put you intake and carb on.
Cost should be about the same as machining your block and getting new pistons.

 

[RacinNdrummin]

Nothing short of the crank, rods and camtrain swaps between these engines, they are a waste of time. 302's can be had dirt cheap, some people give them away.

 

[breidhaupt]

i reckon yall are right bout swapping the motor for a bigger one but i've always liked being different. everyone told me i was nuts for wanting to turbo my 2.3l ranger too. well until i showed them the videos of one going down the 1/4. i'm not wanting to go all out. i only want to bump the thing up to about 175-200 hp. it was my uncles truck and he is close to passing away. i want to keep it as close to the way it is as far as powertrain but i dont mind making part swaps.

 

[COPPERHEAD85]

Its great to think that way about your uncle.
Take the engine out,clean and paint it up nice,put it on a stand in the garage.........then put a 302 in your truck but if I had it to do over I would have went with a 351W with a C-6.

 

[baddad457]

Bore it to 4.000 it will be a 302, no special head basket is needed.
With your heavy truck I would look into a 351w.

Can't bore the 255 to a 302. Not enough meat in the block to start with.

 

[baddad457]

i was thinking of a 0.030 over bore but the only pistons i can find are oe compression flat tops. my only alternative to raise compression is shaving the heads and thinner compressed copper head gaskets. i was also thinking of stoking it with 5.400 rods and crankshaft. but with the full out bore and stroke i would only displace 278 c.i.d. or 4.6l. i wouldnt think that the bigger valves from a aftermarket head would clear the cylinder bore.

You're right, bigger valved heads won't clear the cylinder walls. And stroker pistons ? For that application, they'll cost you more than the whole stroker kit for a 302 block. You're pretty much at a dead end with the 255 as far as upgrading the HP rating.

 

[breidhaupt]

all the parts on summit for boring and stroking would run me about $700 then the cost of machining the block so it's not as expensive really.

 

[originalnitro]

all the parts on summit for boring and stroking would run me about $700 then the cost of machining the block so it's not as expensive really.

Your looking at about another $500+ to balance the rotating assembly and machining and notching the block for the longer stroke.$1200+ for 278 cubes.

Late model 5.0/302 around $800 rering kit (rings and bearings) $300. Around $1100 for 302 cubes and better heads.

Just something to think about.

 

[baddad457]

all the parts on summit for boring and stroking would run me about $700 then the cost of machining the block so it's not as expensive really.

There are no stroker kits for a 255 block. Period. The only way to do one would be to order custom pistons and those are going to cost you more than a stroker kit for a 302 block alone.