E7 OR GT-40 P

[TCBM4]

What would be the best heads to put on a stock 86 gt vert ? e7 or gt 40 p.
How much hp increase can i expect ? Will it still work with speed density comp ? I would like to get aprox 270 to 300 hp without switching to MAF
so I would like to keep the stock cam .


Any thougths would be helpfull { i'm sure this has been ask a hundred times so i'm sorry if the question is redundant }


thanx ,
tom

[Mike Croke]

Those power numbers are optimistic if you're talking about rear wheel power. I'm running E7s that I did some mild exhaust porting on, a Cobra intake, 70mm throttle body, stock cam, and an EEC from an '88 (still speed density). I've also removed the power steering, smog pump and A/C and the car put down 242hp at the rear wheels. That's probably 285hp at the flywheel. With the stock '86 EEC, the car would only make 225rwhp and the air/fuel ratio was awful lean at the top.

You're prime limitation with the '86 is the pistons have no valve reliefs. Thus, you have to check clearance with any head swap. Generally, putting E7s on is not a problem but the GT40s have larger valves and need to be checked.

Also, be careful of the "cheap" heads. You can get a set of used E7s ($100), get a valve job done ($80), get them milled for a little more compression, ($50), put new springs in them ($60), and maybe have them ported ($200). Congrats, you now have spent $500 on stock heads. For another $100, you can get much better used aluminum heads that will make significantly more power than the factroy iron pieces. If you go with the E7s, be very mindful of getting nickel & dimed to death.

[v8only]

Those power numbers are optimistic if you're talking about rear wheel power. I'm running E7s that I did some mild exhaust porting on, a Cobra intake, 70mm throttle body, stock cam, and an EEC from an '88 (still speed density). I've also removed the power steering, smog pump and A/C and the car put down 242hp at the rear wheels. That's probably 285hp at the flywheel. With the stock '86 EEC, the car would only make 225rwhp and the air/fuel ratio was awful lean at the top.

You're prime limitation with the '86 is the pistons have no valve reliefs. Thus, you have to check clearance with any head swap. Generally, putting E7s on is not a problem but the GT40s have larger valves and need to be checked.

Also, be careful of the "cheap" heads. You can get a set of used E7s ($100), get a valve job done ($80), get them milled for a little more compression, ($50), put new springs in them ($60), and maybe have them ported ($200). Congrats, you now have spent $500 on stock heads. For another $100, you can get much better used aluminum heads that will make significantly more power than the factroy iron pieces. If you go with the E7s, be very mindful of getting nickel & dimed to death.

That's some fantastic advice!! I was going to say that an e7 swap on a bone stock 86 engine won't get you more than 225-230 horse at the flywheel without doing additional work, as the e7 head swap is about a 25 horse gain. Don't forget to use the 87 + upper intake too, as it flows better than the 86 one.

Hey mike, I don't know what is involved in porting, I have a set of e7 heads I am about to swap on, but they are bone stock. Can you port without removing valves/springs, or must those come off?? Is there a home job I can do on them??

What is the difference between an 88 speed density ecu and an 86 speed density ecu?? I actually have an 88 speed density ecu I can swap into my 86 when I do the head swap. Is this essential?? Is it a direct bolt on??

Not trying to hijack a thread (we both have 86 gt verts, and are doing the exact same thing!!)

[jazzcat2001]

only way you are hitting 270 to 300 at the wheels with that set up is to spray...id find a set of nice aluminum heads like previously stated...ford dealerships have an idle air adjuster that goes inbetween the IAB and the throttle body that is amazing..i was running an x cam with ported stock e7s with speed density in my 88 :twisted:

[PNY XPRS]

Also, be careful of the "cheap" heads. You can get a set of used E7s ($100), get a valve job done ($80), get them milled for a little more compression, ($50), put new springs in them ($60), and maybe have them ported ($200). Congrats, you now have spent $500 on stock heads. For another $100, you can get much better used aluminum heads that will make significantly more power than the factroy iron pieces. If you go with the E7s, be very mindful of getting nickel & dimed to death.

The question I have about this part...
If you get the fancy Alum heads... knock off the $100 for the heads and the $200 for porting (even though they probably could use a little spot porting) You will still need to spend bucks on the valve job and springs... after you've dumped $700 on the Aluminum heads... and you still need to check PtV clearance due to different valve location and chamber size. depending on the heads you choose.

$500 vs $800 plus is still something some people have to consider. Especially if you can do your own porting or cheaper access to the E7s

[1hot86gt]

a iron head will make more hp on a stock compression motor , well atleast thats what i have heard

[FoxChassis]

I have $300 into a set of E7s.

Purchased price: $50
Clean and magnaflux: $50
Thermactor 'bumps' ground smotth with port roof and exhaust ports polished: $FREE (done at home with borrowed compressor and grinder)
Five-angle valve job, resurface, new valve stem seals, and new core plugs: $200

[Mike Croke]

I'm not against porting E7s. It can be a great budget way to increase power over E6s. I'm merely warning folks that unless they're careful, the E7s will nickel and dime up to a nice set of aluminum heads. The trouble most folks have is they get the E7s for cheap and think that they're going to spend $50 porting them and be done. Then decide a valve job is only $x and a little milling to get the flat is only $y and some new valve seals are only $z. Once the heads are at the machine shop, that's when you find out that a few valves are bent (no big deal at $5 each), a couple valve guides are too worn (again only a few bucks each). By the time the heads are on the car, they're not $100 anymore, they've escalated to nearly $500.

Bear in mind that the folks who claim good power from porting stock heads usually can do all the work themselves. Also, many folks are restricted to iron heads by class rules. If they could run aluminum, they would. Show me a drag racer that doesn't want to get 50lbs off the nose of his car and gain power.

Hey mike, I don't know what is involved in porting, I have a set of e7 heads I am about to swap on, but they are bone stock. Can you port without removing valves/springs, or must those come off?? Is there a home job I can do on them??

What is the difference between an 88 speed density ecu and an 86 speed density ecu?? I actually have an 88 speed density ecu I can swap into my 86 when I do the head swap. Is this essential?? Is it a direct bolt on??

To port, the heads must be disassembled. If for no other reason, you will have metal shavings/dust getting into the valve seats and valve guides that won't clean up easily with everything still assembled. Also, with the valve in place, the most you can do is clean up the ports and not touch the bowls. Try this link for porting ideas: http://www.cmc.net/~xero/Mousesporting.html

The difference in the EECs is the fuel curves. The E7s have better breathing at higher revs compared to the E6s. Thus, the engine will lean out over 4500rpm. I didn't discover this until the car was on a dyno a year ago.

If you get the fancy Alum heads... knock off the $100 for the heads and the $200 for porting (even though they probably could use a little spot porting) You will still need to spend bucks on the valve job and springs... after you've dumped $700 on the Aluminum heads... and you still need to check PtV clearance due to different valve location and chamber size. depending on the heads you choose.

$500 vs $800 plus is still something some people have to consider. Especially if you can do your own porting or cheaper access to the E7s

Depends on how used the heads are. There are lots that have fairly low miles and won't require any work at all. You're right about the piston-to-valve clearance problem. But you'd have to be a wizard first time porter to get your backyard E7s to make anything close to what the aluminums can do out of the box. Plan on 15hp from the (unported) E7 swap compared to 40hp+ from aluminums. If you're able to do good porting, you can get the E7s up to 20-25hp, but to match the aluminums takes serious machine work that makes the E7s cost as much or more than the aluminums. It's very budget dependent.

a iron head will make more hp on a stock compression motor , well atleast thats what i have heard

All other things being equal, this is true. The reason is the isn't as thermally conductive as aluminum, so more of the combustion heat stays in the cylinder to push the piston down instead of being conducted to the water jackets and dumped out the radiator. However, all aftermarket aluminum heads flow so much better and have better combustion chamber design that the small difference in efficiency is overshadowed by the air flow. I'm waiting for someone to do this comparision using the Dart Windsor heads which are supposedly the same casting available in iron or aluminum.

[madmike8]

Just wanted to note... that when your buying used heads... weather they are iron or aluminum... they can nickel and dime ya to death...

Things like bent valves, seals, guides, valve job, all need to be checked/fixed/replaced along with checking for warpage... Just because you spend $700 for your aluminum heads doesn't mean they are ready to bolt on and go... You may find they are... and you may find yourself wishing you spent the $1200 for new ones...

[Mike Croke]

Yes, you're right. Used heads can always be suspect regardless of their alloy. Usually, the aluminums have lower miles than the irons since most folks put the aluminums on for a weekend/track car. Also, the aluminums must be closely inspected for stripped threads as it's much easier to damage them compared to iron.

[Evil86lx]

Hey mike I really like the power #s you have gotten with that 86 motor..

Do you think you could give me a run down on the exact combo!!!!

If i remember correctly you are spraying it also.. correct?

I just happen to have a 87 ECU.. Is it the same as a 88?

Thanks

kyle

[Mike Croke]

Originally, I had an '86 GT that got totalled in the spring of '93. I swapped the pieces into the Crappee in the fall of '93. When the engine was in the '86 GT and had a mere 4000 miles on it way back in 1987, a connecting rod broke and the engine was rebuilt (according to the repair receipt) by the dealer under warranty. Many years and miles later, I pulled the E6 heads off to remove the thermactor bumps and mill them for higher compression. I discovered that the pistons on the '86 engine had valve reliefs. Don't know if they were there from the factory due to a very late build or because the dealer rebuilt the engine. The car did have an '86 block and did have all other '86 parts, just the pistons were the later style.

So the engine consists of:
- stock short block
- some E7s that I ported on the exhaust side only
- stock cam
- 1.7 Crane Cobra pedestal roller rockers
- Cobra intake
- 70mm Edelbrock throttle body
- 88 speed density EEC
- MSD digital 6
- 1 1/2" shorty headers, 2 1/2" off road pipe, 2 1/2" Hooker Max Flow mufflers
- no power steering, no a/c, electric fans instead of clutch fan

Car makes 242hp @ 4800rpm & 282ft-lb @ 4100 rpm at the rear wheels. I haven't measured the power with the nitrous yet.

87 and 88 EECs should be the same.

[Evil86lx]

Sweet... thanks..

I'll pull the heads and check my pistons since the car's build date is pretty late in the year..

I have zero experience with 86 motors.. And having three project cars kinda limits the funs.. So I plan on using the 86 short block..

kyle

[Anonymous]

i've got a set of edelbrock performer heads that i picked up for $240 shipped to me bare, yeah they needed new valves which either i ordered from edelbrock or got chevy valves of the same size to fit kinda weird, paid $250 for the valves from Summit, and then my Comp Cams cam kit came w/ matching valve springs so like $125 there. so i'm $635 into my heads and they should run out quite nice, we'll see in about a week when i start the motor up

[MR GO FAST]

Ok Im stupid here. If my 86 has the flat tops can I still use the E7's? I was thinking of doing that with 1.6 rockers and an 87 intake. Can I notch the pistions enough for a 1.7 rockers?

[Evil86lx]

From what i understand. You can use the E7s and 1.7 rocker's. I have not had the chance to check everything yet. But as soon as i get the title situation figured out i am pulling the heads off of my 86 motor and going to check the clearence with E7s and 1.7s.

This will be my first time with a 86 motor and I'm trying to find cheap power cause the vert is consuming all my spare cash right now..

kyle

[Zap's 85 GT]

If you are going all-out for performance on a stock 86 bottom end, then this set of Trick Flow heads is in my opinion the way to go. http://store.summitracing.com/productdetail.asp?p=1941

My buddy did this swap on his 86 ex police car. He did a lot of research before he ordered these heads but I can confirm they wont hit the pistons even with the Trick flow stage 2 cam and Ford Motorsports 1.72 ratio roller rockers. His best time was a 12.1 @ 113 mph on a 100 shot of nitrous. http://www.ukstreetracers.co.uk/carpage.php?U=SneakyPete This run was before he installed the Tremec trans, supercharger and the 347 stroker. He's had a few electrical gremlins and has been sorting the car out thru the winter. Hoping for low 11's or high 10's this season.

You will definitly need to convert the engine to a Mass-Air setup. This swap isnt cheap but is the best thing you can hope for while sticking with the 86 shortblocks pistons. Just another option.

[MR GO FAST]

From what i understand. You can use the E7s and 1.7 rocker's. I have not had the chance to check everything yet. But as soon as i get the title situation figured out i am pulling the heads off of my 86 motor and going to check the clearence with E7s and 1.7s.

This will be my first time with a 86 motor and I'm trying to find cheap power cause the vert is consuming all my spare cash right now..

kyle
im with you on that...this is why i want cheap HP cause i dont want to take away from my coupe.

[85_Capri_4v]

Ok I know this is an old thread and most likely no one is reading it anymore but I just have to state something after reading the whole thing.

The titla was "E7's or GT40-P?" No one mentioned the P heads in these threads, period why is that?

Capri

[richpet]

As cast, the P heads will make more power than the e7 heads. However, you will need a different set of headers due to the exhaust port height on the P heads and those run better than $250. Both are good heads, both respond to port work. I would Guess (note use of word guess) the P heads worth maybe 25-35 more horsepower with similar work. Sound accurate to y'all?

[85_Capri_4v]

The reason you need the headers is not because of the exhaust ports at all. The ports are in the same location as most other SBF heads especially production heads. The reason you need P specific headers is they relocated the spark plug more centrally. Where as the regular heads E5's E7's etc have plugs screwing in at approx a 45° angle the P heads have an approx 30° angle which causes the plugs and / or boots to hit the primary tubes.

If youhave read anything about the P heads and I can dig up some web articles they are in general a 40 HP gain 25-35 is a safe range to estimate but in general I have seen 40 HP with stock cam and whatever intake was used prior. The power gains from this head are mainly from the fact that it has HIGH VELOCITY ports. Small valves yet they move a lot of air. also the chamber is quite tight, around 58cc.

Porting these heads are very tricky because they flow so well to begin with. personally I would not attempt to home port these puppies with out the use of a flow bench. these heads flow so well they actually out flow or basically out flow the old awesom J302 heads and the j302's had larger valves.

Here is a site to check common heads flow ratings:

http://www.allfordmustangs.com/Detailed/630.shtml

If you are not worried about saving weight these heads are sweet.

CAUTION: Be very aware of people selling GTP heads with over size valves in them or having ported them. I see them on eBay often and if they do not have flow sheets to go with the heads don't buy them, they are most likely boat anchors or door stops.

Anything else just write in. ~ Capri

[HTs83]

It is also my understanding MAC L/Ts will fit P heads. This is only heresay, so take it for what it's worth.

[richpet]

I stand, or rather sit, corrected. I was misinformed about the reason for the special headers. AN old dog CAN still learn new tricks...