difference in 5.0 blocks

[graysonracin]

what is the difference in an 86 5liter vs say a 90 5liter. Ive heard but dont remember. Thanks!

[mustangrfast88]

think block is the same i want to say different pistions

[Gearhead]

block is exactly the same - piston's are different in 86's-true flat tops w/no valve reliefs if I remember correctly. Can't really use any type of aftermarket cam with them.
And, also a crappy cylinder head in 86.

[2Kblacksleeper]

What is a xxx block then? I also got that block when I picked up my coupe.

[Gearhead]

What is a xxx block then? I also got that block when I picked up my coupe.

just a roller cam 5.0 block, they also can have YYY cast in them as well, no difference between XXX and YYY roller cam blocks.

[03z06vette]

I have talked to different people and they have all said that the xxx block is stronger??? anyone know for sure??

[Gearhead]

I have talked to different people and they have all said that the xxx block is stronger??? anyone know for sure??

All factory roller blocks from 1985 and up are the same. Doesn't matter whether it's an XXX or YYY block.

I'm sure someone will chime in and say one or the other has a higher nickel content, blah, blah....

[Kevin1989]

ive read the only thing thats "stronger" is a mexican block but there seems to be some debate about that.

[2Kblacksleeper]

He said that the xxx block was supposed to higher nickel content. Who knows. Its hard to believe a seller when your buying things you can't prove. I just took it because it was thrown in.

[NXcoupe]

It's a stock 5.0 block, they all suck. you can throw all the nickels you want to in it, it will still split in two at 500 hp or thereabouts.

[Stangman]

ive read the only thing thats "stronger" is a mexican block but there seems to be some debate about that.

I've got one of those... they are from trucks. And they are not roller. I have a thread about those from like last year, Gearhead was kind enough to post a comparrison picture of the main caps. You can see the difference.

I have seen, however, a difference in the casting numbers in later roller 302's, like out of trucks and stuff... the "XXX" is in a slightly different spot, and the lifter valley says "302". Other than that I've noticed no difference in the actual "beef" of the block. All cast in different foundrys I'm sure.

[facemelter71]

The Mexican Block obviously came from Mexico.Higher Nickel content of the metal they used for the Block. Those block's were for Ford's warranty replacement's in most of the F-series and E-series line up.Some made there way into the cars.

[85_SS_302_Coupe]

I will say, it seems like i've seen far more XXX blocks than YYY blocks. I always call them the Vin Diesel blocks :lol:

[graysonracin]

Thanks i thought that the pistons were the difference.

[85_SS_302_Coupe]

Thanks i thought that the pistons were the difference.

Only in '86...all the other roller blocks were the same except for the other non HO engines that had cast pistons and then the later hypereutectic pistons from '93 up i believe. The '86 is the only year you need to steer clear of because of the lack of valve reliefs.....BUT i have heard of people cutting reliefs in them which will give you some decent compression since they're true flat top pistons, but i don't know how much you can cut out of them before they get too thin to be safe.

[egbertnr]

A boss block is what you want! Like I have in my car.