all,

I have a chance to buy a set of GT40 heads...all the seller can tell me is he sees a code "GT" and "3D50". I've searched the archives and found that the GT40P have a "P". How can you confirm if the heads are regular GT40 and not GT40P? I have my 351 apart from my 94 F150 and and would pick up these heads if they are regular GT40's (don't want header surprises trying to match up the "P's" to my BBK headers.

Thanks in advance and apologies if I missed the answer in the archives.

Kind Regards,

 

The GT40 heads will have 3 vertical bars on the end, while the P version had 4 bars.

 

perfect. thanks!!

 

Remember you will have to enlarge the head bolt holes to provide clearance for 1/2" bolts if the heads are from a 302, since that engine uses smaller 7/16" bolts.

 

Is the difference between the p and non p heads intake volume or combustion chamber size/shape? I too have a 351 and am pondering the swap. Either way, how much would I be missing between the P and non P when taking into consideration that the heads currently resideing on it are the HO heads it came with?( I am assumming the only diff between the non-HO and HO is the carb and cam?)

Cheers!!

 

The P heads spark plugs stick almost straight out at a 90 degree angle and make putting headers on the motor almost impossible, they're generally not worth the trouble unless you can fab custom headers.

Both the GT40 and GT40P heads are upgrades from the regular heads.. which is all the 351HO came with. The GT40 heads have 160cc intake ports, 1.84/1.54 valves, and 65cc chambers, while the P heads got 1.94/1.60 valves.

 

Thank you for clearing that up. The famed explorer heads are "p" aren't they?

 

The Explorer got both actually...

 

I was just about to correct you on the valve sizes, then you just did it yourself by posting that casting info. GT-Ps (97-00 explorer) have smaller exhaust valves than regular GT-40s, but flow more, showing they have better velocity. Oh, and intake ports I believe are only around 145-155cc same as the standard 40s, maybe 160 is an advertised number? But better than the E7TEs 124cc.

 

wow. the E7's only had 124cc on the intake. ouch. that helps put the GT40 and the World Jr's into perspective. thanks!

 

Yeah.. I remember reading that somwhere too, could have been one of the Ford performance books I have at home. The chart also shows a range of combustion chamber sizes for all the heads, which is accurate as I'm sure there were more than 1 engine plant producing parts at any time, and tolerances vary depending upon the amount of maching the castings got.

 

Thanks for posting that cylinder head data Conanski. One usually sees only the old data from the start of small blocks in 1962 until the late 70s. The data you posted almost looks like official Ford tables. Where does it come from?

I see it is missing some items like the E6SE and pre 85 351W. Any idea if a comprehensive listing of this kind of stuff exists?

 

I have a question. Would 96 explorer GT40 heads fit on a 93 5.8L EFI

 

See post #4. The 302/5.0 heads use 7/16" head bolts, the 351/5.8 uses 1/2" bolts. The smaller holes can be drilled by a machine shop so they can swap to the 351; special step "reducer" washers are available to make the 351 heads work on the 302.


Pete

 

The reason I ask is that if I go to Jegs or Summit for gt40 heads they want megabucks where as if I go to Rockauto and look up stock heads for the 96 explorer I get:
<TABLE class=main style="BORDER-RIGHT: 2px groove; BORDER-TOP: 2px groove; BORDER-LEFT: 2px groove; BORDER-BOTTOM: 2px groove; BACKGROUND-COLOR: white"><TBODY><TR class=part0 id=table379part0><TD><TABLE class=parts><TBODY><TR><TD class=left><TABLE class=layout><TBODY><TR><TD>MARSHALL Part # H3195 {Remanufactured}
CAST# F3ZE, F1ZE, HAS 3 BARS ON FRT OF HD WITH 1/2" HD BOLT HOLES. W/O THERMAL EMMISSION HOLES IN HEAD</TD></TR><TR><TD>* Non-stock item--shipping delayed up to 7 business days

Now somebody said that the F1ZE heads were gt40s
</TD></TR></TBODY></TABLE><TD class=right></TD></TR></TBODY></TABLE></TD><TD class=center id=node379part0price>$195.79</TD><TD class=center id=node379part0core>$100.00</TD><TD class=center id=node379part0total>$295.79</TD></TR></TBODY></TABLE>