What years are considered \'early\' 302\'s?

2768 Views 17 Replies 10 Participants Last post by teyerdhal, Jun 22, 2012

tminus3

Discussion Starter · Apr 21, 2006

On the forum there is a lot of reference to early vs late 302 blocks, especially regarding block strength & weight. Up to what year are 302's considered 'early'?

The reason I'm asking is the fact that I recently weighed a bare original bore '79 302 block, and a bare original bore '72 mexican block. The weight was 127 lbs without main caps for both blocks.
Does his make a '79 302 an 'early' block?

1 - 18 of 18 Posts

mikemustang289

· #2 · Apr 21, 2006

the reason they refer to it as early is because they are non-roller blocks, should be 68-82? At some point in the 80's the roller block was introduced and that is what is referred to as the Late 302's

tminus3

Discussion Starter · #3 · Apr 21, 2006

I believe the first year for rollers is '85 (at least in the Mustang it was). So pre-roller block equals 'early'?

<font size=-1>[ This Message was edited by: tminus3 on 4/21/06 8:30pm ]</font>

393Clevor

· #4 · Apr 21, 2006

Plus sometime in the early 70's the raised the deck hight, then sometime in the 80's they went back to the shorter deck. I'm not sure what the dates were but a 79 block has the taller deck.

tony

· #5 · Apr 21, 2006

1974 started the raised deck to lower compresion during the gas shortage of the 70's. They lowered it I believe when the roller blocks came out.

393Clevor

· #6 · Apr 21, 2006

I think it was in 80.............I have an 80 block in the HemiEater and with the 90 5.0 pistons I'm at 0 deck............

tonys10sec306

· #7 · Apr 21, 2006

Any 302 before 1980 is early to me. after 1979 ford went to a lighter block

Das Jager

· #8 · Jun 17, 2012

tonys10sec306 said:
Any 302 before 1980 is early to me. after 1979 ford went to a lighter block

Can someone show me proof of this lighter block? I've got a E7TE and a E0AE and I really don't see a lot of difference between the two. The main caps look the same. The decks look the same. The only obvious difference is the roller cam mods in the valley and the rear main seal.

fastEd

· #9 · Jun 18, 2012

Early and late can also refer to 1980-earlier vs. 1981-later, when the change was made from 28 oz. to 50 oz. imbalance.

cheers
Ed

bmcd66250

· #10 · Jun 18, 2012

393Clevor said:
Plus sometime in the early 70's the raised the deck hight, then sometime in the 80's they went back to the shorter deck. I'm not sure what the dates were but a 79 block has the taller deck.

Hmmm, 6 year old thread.
The D4 blocks (74 - 77) had the raised decks. D8 blocks (1978 - ) the decks were lowered again.

I would consider a 79 block an early block.

PSIG

· #11 · Jun 18, 2012

I would agree with the last few posts, as the significant changes were made in '80. They also changed the dipstick location to the side, deleted the clutch pivot boss, and slightly changed the distributor shaft diameter IIRC. In-spite of all that, I have never seen any true (or at least noticeable) difference in strength, and most info seems to be Urban Legend. Ford rates the later blocks at 7000 rpm and 400 hp, though (with a good tune) they seem reliable to 450-500 if the rev's are kept down, or 550-600 with lower rev's and boost. They can often go higher, but it's a crap shoot and all in the hands of the tuner if built well.

The primary failure point is the caps, as they pull away from the block registers and crack the block at the main cap bolt holes, often splitting it in half. Surprisingly, I have not seen that the heavy K-code and Mexican caps reduce this problem substantially, though I would hope it helps somewhat. Girdles (due to geometry) are considered useless, but hearsay indicates keying the caps is useful. This means balancing is critical for high numbers, along with good tune and a compromise between rpms and HP. Like any block limitation, they can take high revs or high power - but not a lot of both. If you're going into that neighborhood, I would consider aftermarket. Thats my 2 cents.

David

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teyerdhal

· #12 · Jun 19, 2012

Late blocks seems to be harder for honing stones..So they should wear slower regardless to their max power limit.

bmcd66250

· #13 · Jun 19, 2012

Agree. I have two spare roller cam blocks in the shed, one with 120K miles and the other with 100K miles, and the cylinders in both are only + .001".

PSIG

· #14 · Jun 19, 2012

Well, don't forget that the newer ones went to thin metric low-tension rings in the quest for mileage with thinner oils. That made a large difference in wear over the fat chromed high-tension iron rings of the past. Between those, the improved stem seals, better oils, and a few other things, life expectancy from late '60s to late '80s effectively doubled. I checked the bores of the Explorer GT40 that I'm turbocharging for the Ranger, and it still has nice cross-hatch and clean bearings with 137k miles. It's not even at half-life if I don't blow it up.

David

teyerdhal

· #15 · Jun 20, 2012

PSIG said:
Well, don't forget that the newer ones went to thin metric low-tension rings in the quest for mileage with thinner oils. That made a large difference in wear over the fat chromed high-tension iron rings of the past. Between those, the improved stem seals, better oils, and a few other things, life expectancy from late '60s to late '80s effectively doubled. I checked the bores of the Explorer GT40 that I'm turbocharging for the Ranger, and it still has nice cross-hatch and clean bearings with 137k miles. It's not even at half-life if I don't blow it up.

David

Sure, theses modern parts and products help life expectancy.
But a honing stone is a honing stone.. If it wear faster when honing late blocks => late block are made of a harder metal...

PSIG

· #16 · Jun 20, 2012

teyerdhal said:
Sure, theses modern parts and products help life expectancy. But a honing stone is a honing stone.. If it wear faster when honing late blocks => late block are made of a harder metal...

Interesting. I have not noticed that at all. I'll have to try a hardness test on a few blocks to see if there is any substantial difference. I have not noticed any difference in hone wear, but I haven't been looking for it either. You'd have to do a lot of the same type of blocks in a row, and then a lot of the other type to see a difference that way I would think. Hones don't tend to wear very fast unless you change something like the honing lube. What kind of hone do you use, which stones, and what lubricant?

David

bmcd66250

· #17 · Jun 21, 2012

PSIG said:
Well, don't forget that the newer ones went to thin metric low-tension rings in the quest for mileage with thinner oils. That made a large difference in wear over the fat chromed high-tension iron rings of the past. Between those, the improved stem seals, better oils, and a few other things, life expectancy from late '60s to late '80s effectively doubled. I checked the bores of the Explorer GT40 that I'm turbocharging for the Ranger, and it still has nice cross-hatch and clean bearings with 137k miles. It's not even at half-life if I don't blow it up.

David

And I'm sure the better fuel metering with EFI eliminates a lot of cylinder fuel wash.

teyerdhal

· #18 · Jun 22, 2012

PSIG said:
Interesting. I have not noticed that at all. I'll have to try a hardness test on a few blocks to see if there is any substantial difference. I have not noticed any difference in hone wear, but I haven't been looking for it either. You'd have to do a lot of the same type of blocks in a row, and then a lot of the other type to see a difference that way I would think. Hones don't tend to wear very fast unless you change something like the honing lube. What kind of hone do you use, which stones, and what lubricant?

David

Not me a buddy of mine, a mechanic and dragstrip man who make a dozen of engines per year for friends.
So i can't give you détails about his honing process..

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