I want to put GT40 or GT40P heads on my 302 and I'm thinking something like a TFS stage 1 cam. Will the stock pistons work with this?
WildWillyWalker
not all or every 1986 engine had the full flat tops....
there were basically TWO different pistons for a 1986..
one is a FUL FLATOP with NO reliefs or dish.
and the other was a common shaped piston with valve reliefs and a dish.
which one do you have or wanna use,....?
the totall full flat top has been used with a head that needs two valve notches...but you have to put the two valve eyebrow reliefs in them.
the original head (E-6) had the valve seats SET IN DEEPER from the head gasket surface...so, that , ...along with the small cam would allow the valves to clear the pistons.
there were basically TWO different pistons for a 1986..
one is a FUL FLATOP with NO reliefs or dish.
and the other was a common shaped piston with valve reliefs and a dish.
which one do you have or wanna use,....?
the totall full flat top has been used with a head that needs two valve notches...but you have to put the two valve eyebrow reliefs in them.
the original head (E-6) had the valve seats SET IN DEEPER from the head gasket surface...so, that , ...along with the small cam would allow the valves to clear the pistons.
Kato
Is there anyway to find out without pulling the heads, production date ,ect?
Any info would be greatly appreciated.
Thanks
Terry
Is there anyway to find out without pulling the heads, production date ,ect?
Any info would be greatly appreciated.
Thanks
Terry
the 1986 full flat top will only fit when UNALTERED when it is coupled with the actual original E6 heads that have the also special deeper valve seat offset from the gasket surface.
all other heads had a "normal" less deeper offset of the seats than the E-6 head.
so,
if the block has the full flat top pistons in it then no other head will fit without hitting.
so,
if you have another head on it, then you must have a different piston.
or someone notched the full flat top pistons.
or just take it apart and LOOK.
many feel that the E6 head was junk at best....
SO,
WHAT
HEAD
IS
ON THE ENGINE NOW....????
all other heads had a "normal" less deeper offset of the seats than the E-6 head.
so,
if the block has the full flat top pistons in it then no other head will fit without hitting.
so,
if you have another head on it, then you must have a different piston.
or someone notched the full flat top pistons.
or just take it apart and LOOK.
many feel that the E6 head was junk at best....
SO,
WHAT
HEAD
IS
ON THE ENGINE NOW....????
The stmble port... didn't do much. That engineer designed the fail boat as well.. Very steep short raduis, supoosed to promote turbulance in the combustion chamber. I guess they were going for the chrysler "lean burn" design. Wich also failed.. but hey, just because chrysler through it away doesn't mean ford shouldn't invest hundreds of thousands in it.
Kato
So basically what you are telling me is it has the 6 then no reliefs and if the 7 it is all good, I have notched some pistons in the past but the coustomer doesnt want to spend the money if you know what I mean, thanks for the help, I am going to check it right now.
So basically what you are telling me is it has the 6 then no reliefs and if the 7 it is all good, I have notched some pistons in the past but the coustomer doesnt want to spend the money if you know what I mean, thanks for the help, I am going to check it right now.
Do any of you know how much clearance it does have if you use the 86 heads, Can I run a e-cam and mill the heads?
If so how many thousands with no problems,(of course the more the better).
Thanks
Terry
If so how many thousands with no problems,(of course the more the better).
Thanks
Terry
I understand about checking with clay and all that, my main question is how much clearance do they have from the factory with nothing done. This will give me a number to work with.
Thanks
Terry
Thanks
Terry
on my 86 I did a lot of searching on both forums, here and foureyedpride.com Seems like as stated above some guys get lucky on a set of Gt40's and then some guys hit with E7's and a stock cam. Based all on production variences. The one head that a lot of guys come into agreement is the Twisted Wedge heads due to their valve angles. So if your the lucky one that has his pistons below the deck surface then maybe your in luck or you could be as much as 5 ths above it and then hitting. Isky does make a tool to cut valve reliefs in pistons but its a tedious job but does work good.
As Kato pointed-out, the stock valves on the E6 heads sit about a 1/8" deeper in the chamber compared to the E7s – which is why they easily clear the flat-top piston (without a ~1/8” deep valve relief.) I don't see any reason the clearance between a stock '86 E6 longblock and a stock E7 longblock is not roughly identical…
You asked about running a e-cam with the stock E6 longblock. Don’t know much about the e-cam, but I don’t see how you can improve performance over the stock cam since the stock E6 heads start wheezing at 4600-4800 rpm.
Like Vinnie and Puter – my E7 swap was a success. I put (home “ported” / cleaned-up) E7 heads on my STOCK, 255,000-mile ’86 shortblock and it ran awesome. I did lots of research on this before attempting it - 5-years ago there were many threads on this subject and the “successes” heavily out-weighed the failures.
In my case, claying the E7 heads gave me about minimum clearance on the intake side – about .090”. Exhaust had so much I didn’t bother to measure it… Again as pointed out – every setup will measure differently so there are no guarantees.
As I said, the engine ran awesome – much smoother past 3000 rpm, and it just felt like it wanted to rev. I ran 1.7 rockers with the Trick Flow (stock upgrade) spring kit. My max shift point went from ~4800 (indicated) to 5300-5400. I blasted it to 6000 a few times in 1st-gear. At the track it ran .4 quicker and picked-up almost 4 mph. I hope I’m not disappointed with my new 331, lol…
You asked about running a e-cam with the stock E6 longblock. Don’t know much about the e-cam, but I don’t see how you can improve performance over the stock cam since the stock E6 heads start wheezing at 4600-4800 rpm.
Like Vinnie and Puter – my E7 swap was a success. I put (home “ported” / cleaned-up) E7 heads on my STOCK, 255,000-mile ’86 shortblock and it ran awesome. I did lots of research on this before attempting it - 5-years ago there were many threads on this subject and the “successes” heavily out-weighed the failures.
In my case, claying the E7 heads gave me about minimum clearance on the intake side – about .090”. Exhaust had so much I didn’t bother to measure it… Again as pointed out – every setup will measure differently so there are no guarantees.
As I said, the engine ran awesome – much smoother past 3000 rpm, and it just felt like it wanted to rev. I ran 1.7 rockers with the Trick Flow (stock upgrade) spring kit. My max shift point went from ~4800 (indicated) to 5300-5400. I blasted it to 6000 a few times in 1st-gear. At the track it ran .4 quicker and picked-up almost 4 mph. I hope I’m not disappointed with my new 331, lol…
I think Mark is being a bit optimistic with the E6 head. They start giving up closer to 4000 rpm. You need to improve the heads before you worry about the cam. Ported E7's with the stock HO stick will go a long way.
The E6 does actually have a use outside of scrap metal and boat anchors. They make a lot of low rpm torque due to the high swirl chambers. Ported, they'd probably make a hell of a stump puller truck motor head, but for higher rpm performance its a dud. It may not be well known here, but those heads were in steady use until 1991 on the non-HO 302 in cars. Tbirds, Cougers, Vics, Grand Marqs, Towncars, all used them.
The E6 does actually have a use outside of scrap metal and boat anchors. They make a lot of low rpm torque due to the high swirl chambers. Ported, they'd probably make a hell of a stump puller truck motor head, but for higher rpm performance its a dud. It may not be well known here, but those heads were in steady use until 1991 on the non-HO 302 in cars. Tbirds, Cougers, Vics, Grand Marqs, Towncars, all used them.
i've had mine up to 6000 rpms.That's plenty.After that,I'm sure something will get altered in the engine.
1986 flat top short block wont work with gt40p
I have delt with 3 of the SEFI 1986 HO engines, all had featureless flat tops. I tried installing GT40P heads (unmilled+stock valvetrain) on an otherwise factory stock 86 short block with fresh gaskets. I used the clay method and it fell substantially short. I do not remember the #'s but I had hauled the gear to the shop at the loal JC where I was enrolled in the cylinder head class, because I wanted to verify that I had done it correctly, I had - and the instructors duplicated my efforts in the classroom environment for the students. I seem to remember that there was less than half the clearance recommended, sorry been 5+ years now.
I have never heard that there were two piston types available in '86 for the HO, perhaps there were on the CFI cars?
1985 Mustangs
* "M" - 5.0 liter 4V (5-speed manual - 210 hp) or CFI (automatic - 180 hp) V8 302 CID
1986 Mustangs
* "M" - 5.0 liter SEFI V8 302 CID 200 hp
Here is one of the 86 powertrains installed in the fun family car
http://www.thatmetalbox.com/89lx_mustang/89LX_mustang_main.htm
The 40P heads certianly will not...
I have delt with 3 of the SEFI 1986 HO engines, all had featureless flat tops. I tried installing GT40P heads (unmilled+stock valvetrain) on an otherwise factory stock 86 short block with fresh gaskets. I used the clay method and it fell substantially short. I do not remember the #'s but I had hauled the gear to the shop at the loal JC where I was enrolled in the cylinder head class, because I wanted to verify that I had done it correctly, I had - and the instructors duplicated my efforts in the classroom environment for the students. I seem to remember that there was less than half the clearance recommended, sorry been 5+ years now.
I have never heard that there were two piston types available in '86 for the HO, perhaps there were on the CFI cars?
1985 Mustangs
* "M" - 5.0 liter 4V (5-speed manual - 210 hp) or CFI (automatic - 180 hp) V8 302 CID
1986 Mustangs
* "M" - 5.0 liter SEFI V8 302 CID 200 hp
Here is one of the 86 powertrains installed in the fun family car
http://www.thatmetalbox.com/89lx_mustang/89LX_mustang_main.htm
Not to hijack WildWill's thread, but can '86 flat-top pistons be easily used in other applications... say in upgrading a '67 289 (if it still has a 4.000" bore?)
even a 289 head will need some amount of pocket or eyebrow made....it all depends on the cams low lift duration.
a full flat top piston will enable you to have the most compression with no valve reliefs...untill you put in the valve reliefs that are needed.
only wat to have more compression is to have some sort of pop up dome...
I have used this stock 86 piston to be the basic start place to have the most compression on a number of different heads.
and then put in the cam, and cut the eyebrows as needed.
the crown of piston is over .280" thick, so a pretty good and deep eyebrow can in fact be put in there without weakening the crown area or making the wrist pin towers get weak..
as said, I have used this piston on Twisted along with straight and spread spaced heads...
it is one of the best to start a project with since there is no dish to loose compression.
but if you do not know or understand how to put in eyebrow shaped reliefs....then do not use it....
a full flat top piston will enable you to have the most compression with no valve reliefs...untill you put in the valve reliefs that are needed.
only wat to have more compression is to have some sort of pop up dome...
I have used this stock 86 piston to be the basic start place to have the most compression on a number of different heads.
and then put in the cam, and cut the eyebrows as needed.
the crown of piston is over .280" thick, so a pretty good and deep eyebrow can in fact be put in there without weakening the crown area or making the wrist pin towers get weak..
as said, I have used this piston on Twisted along with straight and spread spaced heads...
it is one of the best to start a project with since there is no dish to loose compression.
but if you do not know or understand how to put in eyebrow shaped reliefs....then do not use it....
Thanks for all the info, Kato – I’m filing it. I bought this 289 a few years ago, so I don’t know if it’s been bored. Those run-of-the-mill 289s came with low compression cast pistons – like 8.2? to 1.
Probably a long-shot that I could use them in this old block, but from what you said – if not - maybe they are desirable enough I can find someone who wants them…
Probably a long-shot that I could use them in this old block, but from what you said – if not - maybe they are desirable enough I can find someone who wants them…
quite often, they will clear with a MINIMAL amount of "open clearance"...but when the engine is up at some higher rpm level, and then you take your foot out of it, the coastingf down will allow the valves to hit quite hard.
this is why you are suppose to have a EXTRA open clearance above the piston.
open clearance DOES NOT MEAN the amount of clearance when the valve is ALL THE WAY OPEN..... but rather, when the piston is near the top, and the valves are open just a little bit.... because total valve lift means nothing in this equasion.
this is why you are suppose to have a EXTRA open clearance above the piston.
open clearance DOES NOT MEAN the amount of clearance when the valve is ALL THE WAY OPEN..... but rather, when the piston is near the top, and the valves are open just a little bit.... because total valve lift means nothing in this equasion.
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