I am not sure, I think theres gonna be a problem but I have a 302 now with bassani headers Im thinking about sapping to a 351 with gt 40 heads will 302 headers fit the 351 and even if I stay with the 302 block I will go gt-40 heads will the stock 302 headers fit these gt-40 heads. basically how much difference head and header wise is there with 351 to the 302 ??

 

Both motors use the same heads, the only difference in them is the size of the bolt holes. 7/16th on the 5.0 and 1/2" on the 5.8. The 5.8 block is taller and wider however, so if you have a single exhaust with a Y-pipe the Y will have to be widened for the 5.8. Otherwise there is no issue using the 5.0 headers onthe 5.8.

 

I knew my guys on FTE would know the answer I love this place thanks again for the help

 

will the long tube headers on my 90 302 fit if i put a 351 in it fro mthe same model year?

-Randy

 

Doesn't matter what year 5.8 you use, but I bet the 5.0 longtubes will hit the frame when installed on the bigger windsor.. unless there is tons of room to spare on the particular set you have.

 

Paul. What about the EGR valve. I know on a 351 it comes out of the front of the exaust manifold passanger side. I know that the 302 is diffrent. I cant remember where it comes from.

Also if you do the 351 swap make sure that you use the flywheel and Harmonic balancer off of the 351. The balance is diffrent between the 2 engines.

 

Yep, so you got 2 choices, add a fitting for the EGR tube or delete the EGR all together.

 

hey Paul, what is needed to "delete" the EGR on a 94 5.8 ??

 

I have researched the gt40 heads and I believe that special headers are needed for them, or some major reworking. Here is an excerpt from a post that I found.


'The P heads have a revised combustion chamber configuration with relocated spark plugs that allows them to burn cleaner without the use of air injection while making good power. They aren't even drilled for Thermactor passages. They also have smaller exhaust valves and are designed to have a higher exhaust port velocity. I have a set which I've done some very mild port cleanup to as well as converted to screw-in studs with guide plates, but haven't yet run them.

They require special P-specific headers (Mac makes a P-specific shorty header for them which I'm told fits well) as the exhast ports are oval rather than square and the relocated spark plugs makes for a tight fit with standard headers. I used an old set of oval tube headers I had for mine, but I had to extensvely rework the driver's side header. I should have just forked over the bucks for the P-specific headers.'

I have a few other posts that corroborate these statements. I don't know if you could maybe use the stock headers from a 5.0 Explorer, but it might be possible.

Hope this helps,

Rob

 

The gt40 heads have spark plugs that extend straight out from the heads, as opposed to the angled plugs found on modt Ford small block Windsors. This is a plus when using these heads on a V8 swap into a smaller vehicle like a Ranger, where clearances at the firewall are very tight on the drivers side as the normal plugs angle back towards that firewall on that side. I myself am saving for a set for my Ranger as well as a set for my F-150.

Rob

 

The GT40-P heads are the only ones with the revised plug angles. The rest of the GT40 heads have the normal plug angles.

 

An EGR eliminator of course.. http://rjminjectiontech.com/?p=9 and a blockoff plate for the valve.

 

My bad, then. Gt40 (no P) heads are very rare, I understand. And pretty expensive. And flow no better than the much more common 'P' types. Didn't mean to put out any bad info.

 

Actually no.. they appeared on '93-'95 Lightnings, '93 Cobra Mustangs, and the '95-'96 Explorer/Mountaineer 5.0, as well as various Ford crate motors since then.