Hi all,

friend has got a F100 pickup with 302 engine. According to datecode it's from 1977

engine code seems to be: D8VE-6015-A3A (or ASA, A5A, ...)
with a big Z behind that and as datecode: 7F24

He changed distributor and asked for firing order, told him the 289/302 firing order. wouldn't run
So I told him to try the 302HO/351 firing order, which runs fine.

So my question is: what does that HO actually mean? hoiw is it different to a 'normal' 302 ?
How can we identify this as maybe he has an aftermarket cam ?!

Any ideas ?

Kalli

 

D8 is for 1978. If it is running on the 351W firing order it probably had the cam replaced. The firing order was changed in the 302 to the 351W firing order in the 80's but I don't recall which year. The reason was it more evenly distributed the main bearing loads, but you couldn't prove it by me. The HO was first to receive the new firing order and then all the 5.0 engines were changed. It may have coincided with the switch to EFI.

In any event, the 351W and 289/302 are drop in swaps for one another with the firing order change being needed.

 

thans for info. what does HOO actually mean? i can't find any reference ?!

 

High Output

 

HO = High Output....

Some differences from "regular production" engines, mostly having to do with tune on later 302s (not much difference on engine internals) IMO mostly just enough difference to allow marketing HO models for a little more money.

In todays huge aftermarket marketplace, the differences in factory HO engines as compared to "regular production engines have been relegated to almost totally insignificant. (As the "HO Parts" will be replaced with better aftermarket parts anyway)

 

ohhhh . and when did that start ??
you know if that started after his engine was built I'd know for a fact that his cam is aftermarket

petec you say D8 is 78. The datecode is 7F24. So does that mean this is an early 78 model engine instead of a 78model built in 87. Year is clearly "7"

Thanks for all your replies. They'll be happy to hear all that

Kalli

 

somebody can correct me if I'm wrong but the HO motors of the late 80's to 95 are built with forged internals and roller cams.

 

93 started hyperutectic pistons in the mustangs on up.

 

Ford used the the first two digits of the part number for date coding as in C for 1960s D for 1970s and so on. The second digit was numeric for the actual year within the decade. The code 7f24 is a casting number I would have to research to find its meaning.

 

If thats the code on the block, the only explanation is a 351W cam. The #1 main difference in HO engines and standard engines was that the HO's have a roller cam, while the standards are just flat tappets. The blocks are different between the two, and it is unlikely that someone retrofitted a roller cam into the block (although it can be done with some machine work and a special cam, I have proof under the hood of my car). The obvious difference in the block is the depth of the lifter bores. The HO motors were 351 firing order, standards were regular 302 firing order. The HO engines were brought in roughly at the same time as the EFI, but not all fuel injected 302s were HO's. The EFI truck engines and some of the less common TBI 302s were standard, non-HO.