[Booger]

well i just picked up a 88 stang for $200 its got the american racing rims, true duals(no h-pipe) headerman headers, offenhauser 360 intake, and a holley carb, electric fan,C4 tranny, valve covers, hurst shifter, and some other goodies. i think thats a ok deal. but motor smoked from pass side and had a lil knock from driver side, pulled off valve cover and head says 351 and the whole valve train is Crane. turns out the No.5 Cyl has a push rod that look like a C and was so bent it was shaving itself on the head-explains noise-. what would cause the push rod to bend that bad? the rest were good just one really bad one. it had flat tappet hydro lifters and a small cam like a b303 but made by carne and the cam had broken edges on the lobes.

my question is what does a 351 head do to a 302 performance wise?
also the heads had homemade port job. how do i tell if the valves are any bigger.

[5-0stank]

i dont think the heads would cause a pushrod to bend...valve springs might???

[1slo5.0]

351W heads and 302 heads are almost identical except for the head bolt holes. 351W heads use a 1/2 head bolt hole and 302 heads use a 7/16 hole. 1969 and 1970 351W castings used slightly bigger valves and possibly slightly bigger ports than the 289-302 heads.

[Velvet Leopard]

Too stiff a valve spring or a bad adjustment will definetly cause a push rod to bend and cause the lifter to dig the cam. Roller lifters would have at least saved the cam's life. This sounds almost like a Chevy Porcupine Modification. I am not sure if the 351's heads have different dimensions water and oil wise, but I know they were NOT designed for the 302 at all. Remember there are three different Base 351 Head designs. Unless the previous owner got specialty parts for this application, I would assume it was an entire hack job. Although it is possible to put big block, and other types, of heads on small blocks, or different types of blocks, which are similar, the cost of the mod would be quite high. I would salvage what parts I could from your engine and either build a fresh 302 or find a good 351 to be sure you have something that fits right.

[1slo5.0]

Originally Posted by Velvet Leopard I am not sure if the 351's heads have different dimensions water and oil wise, but I know they were NOT designed for the 302 at all. Remember there are three different Base 351 Head designs. Unless the previous owner got specialty parts for this application, I would assume it was an entire hack job.

Why is that? All Windsor heads are interchangeable. Everything (steam holes, bolt holes, etc) are the same with the exception of the bigger head bolt holes on the 351W. Most aftermarket heads have the big bolt holes and use a reducer if you put them on a 289-302 based engine. Using 351W heads on a 302 does not consititute a hack job. It is probably a waste of time and effort but is far from a hack job.

[Velvet Leopard]

But the deck of a 351Wis higher then a 302, at least mine is about two inches higher. Wouldn't that upset the alignment of the heads, block, and manifold?

[1slo5.0]

Originally Posted by Velvet Leopard But the deck of a 351Wis higher then a 302, at least mine is about two inches higher. Wouldn't that upset the alignment of the heads, block, and manifold?

The deck height of a 351W is 1.3 inches taller than a 302 but that doesn't have anything to do with the heads. 351W uses a different intake than a 302 due to the difference in deck height.

[Booger]

well i had just bought the car for parts for my other 302. i was just woundering if stock 351 heads did anything for the hp, looking closer at them tonight it looks like a cheap port job and maybe bigger valves?? what size are stock valves and how do i check on the 302 heads?

[1slo5.0]

Originally Posted by Booger well i had just bought the car for parts for my other 302. i was just woundering if stock 351 heads did anything for the hp, looking closer at them tonight it looks like a cheap port job and maybe bigger valves?? what size are stock valves and how do i check on the 302 heads?

Most 302 heads (including E7) use 1.78/1.46 valves. Most 351W heads use 1.78/1.46 valves also but 69 and 70 351W heads use 1.84/1.54 valves. Either way you are looking at a minimal horsepower gain which you won't even feel. I'd look for a set of GT40P heads from a 97 1/2 and newer Explorer 5 liter.

[Booger]

what kind hp gain would i see from those

[1slo5.0]

Originally Posted by Booger what kind hp gain would i see from those

GT40P heads will give you about 25-30hp.

[MSO]

and GT40P heads come standard on the 5.0 explorers u speak of? or is it some kind of special package or sumthing?

in other words, u can jus find one in a junk yard and take them off of that?

[ChrisJ]

Originally Posted by My'StangOpens and GT40P heads come standard on the 5.0 explorers u speak of? or is it some kind of special package or sumthing? in other words, u can jus find one in a junk yard and take them off of that?

yes they come on the explorers...

My roommate went with 351 heads and he bends pushrods like none other...

Go with the GT40 set-up...IMHO

[MSO]

there has to be a catch.. they're cast iron aren't they?

[1slo5.0]

Originally Posted by My'StangOpens and GT40P heads come standard on the 5.0 explorers u speak of? or is it some kind of special package or sumthing? in other words, u can jus find one in a junk yard and take them off of that?

Yes, all 97 1/2 and up 5 liter Explorers

Originally Posted by My'StangOpens there has to be a catch.. they're cast iron aren't they?

No catch at all. Yes they are cast iron but they are the best factory head Ford makes.

[jrcurtis00]

I have a 91 lx coupe. 302 engine. I am in the middle of rebuilding the 302. I have mounted a set of 351 heads with headbolt spacers. The only other difference i've come up with is the size of the ports. Can I resize the ports on my set of gt40 intake or should I look for another intake. I have quite a bit of money tied up in the heads.And i was so wanting to use the gt40upper and lower since I spent about a week polishing the upper.

[AdderMk2]

thanks for bumping an almost 4 year old thread....

damn newbs