So here's the scenario I have an 87 ford f-150 with the 351w HO motor. The motor is no good and I picked up a 92 351w with EFI to replace it. I am staying carbureted.

So my question is this which cylinder heads will flow better the HO or efi?? I am going with an edelbrock peformer rpm cam and inake. Eventually I will get the performer rpm cylinder heads but for now was wondering which ones out of the HO and efi would yield better performance gains?

I had a link at one time with cylinder head flow numbers but can't seem to find it.

Any help it very much appreciated.

 

Both of those engines will probably have the E7TE heads, if so then they will be equal.

But to be sure check the casting numbers.

 

I'll be checking the casting numbers this weekend when I pull the old motor out. Are these located under the valve cover?

 

Casting numbers are on the head gasket side, so you at least need a mirror to see them with the intake off. The HO motor may have E5 heads but it could have E7's like the '92, the E5's are almost identical but have slightly larger combustion chambers so the nod goes to the E7's.

 

I just looked at my 1994 351W engine, and there is a "T" cast into the top corner of each head. Do yours have this "T"? I assume mine are E7TE.

I'm not quite sure of its significance, perhaps others can weigh in.

 

Yes that signifies the E7TE heads, the E5 heads will have an R in the same location.

 

I just looked at the heads that came off my HO motor or what I thought was the original HO motor in my truck and it has D7OE heads and the motor is bored .030 over. Haven't pulled the heads off the 92 motor yet

 

I just checked the 92 motors head for the T and it has the T on one side and a 5 on the other

 

The only spec I have for D7OE is for 302 heads, if that's what they are they will have 1.78/1.45 valves and 69cc combustion chambers.

But if the heads have 1.84/1.54 valves they are 351 heads with 60cc combustion chambers.

Are there any casting marks on the top side around the rockers identifying them as 302 or 351? If not you need to measure the valves.

 

As best I can measure in with a tape measure and flash light I giot 1 7/16" on the small valves and 1 13/16" on the big valves



Now that I measure the smaller valves a little more carefully they're just under 7/16 mark about halfway to the next smaller mark I need a micrometer or something to get a more accurate measurement

 

Well 1-7/16" is 1.438", so most likely those are 1.45" exhaust valves.

1-13/16" is 1.81", which is right in between the 1.78" and 1.84" intake valve sizes. However 1.78" is the size that should be found paired with the 1.45" exhaust valve, and if so, they will measure a smidge under 1-13/16".

I think some of the later "good" production heads still use the small valves. And also for some years in the '70s 302 and 351W heads were the same piece except for head bolt hole size.

Are you sure that the "5" on the head is not an "S"? That would be in keeping with the T and R markings.

The E7TE head will be much better than the D7OE units. Hopefully the other head is a match for this head.