e7te heads going to the machine shop

have them shaved 25 to 40 thousanths. a 30 degree cutback on the intake valves helps too but don't spend much on them.

I wouldn't mill the heads more than .020" . . . you start getting into slotting the intake manifold hole territory after that.

You can do the exhaust bump yourself if you have the time.

What block are you putting them on? Are the pistons flat top or do they have reliefs cut into them?

I have something to follow up on this....

I have an 86 GT that has UDP, FMS headers, O/R H, FLowmasters, 3.55's, Hurst Shifter.

I am planning a MASS air swap as i have all the parts. also i was going to install a fresh set of E7's that i have. I wondering about the piston to valve clearance issues that i may experence since the engine has flattops.

I wouldnt waste any time on the e7's unless you are unwilling to spend anymore more money on your car. if you have the valve reliefs cut into your pistons I would look more at a set of aluminum gt40's.

Chrome_Rust said:

I have something to follow up on this....

I have an 86 GT that has UDP, FMS headers, O/R H, FLowmasters, 3.55's, Hurst Shifter.

I am planning a MASS air swap as i have all the parts. also i was going to install a fresh set of E7's that i have. I wondering about the piston to valve clearance issues that i may experence since the engine has flattops.

Click to expand...

You're into the TOLERANCES OF THE BLOCK, HEAD, PISTON, VALVES, GASKET, ETC at that point.

So, for SOME people, they will have enough clearance. OTHERS will not. Of course, that's assuming new valve springs. With old valve springs, then it's foolish either way.

IMHO, if you don't know, or have the tools/desire, to check for valve to piston clearance, then ASK yourself, is it REALLY worth that extra ~5HP in the mid/upper range? E7's loose some HP/torque from idle to ~1.5K verses the high swirl E6s.

The above is reality. I'm sure that you can find many posts that tell you otherwise.


If you want more HP in the upper range, then switch the intake and TB. Again, the '86 TB and upper are designed more for low-end to mid-range. The '87-93 upper and TB are a direct swap. IMHO, a pre-?98? Explorer is a better choice. The ?98+? intakes are better if you don't have to pass smog and don't need the EGR.

IMHO, I would not recommend notching the pistons while they are in the engine. It's nearly impossible to ensure that no metal fillings get into the rings. The stock 5.0 has low tension rings to begin with. So, it doesn't take much damage to have them start loosing compression.

Four Eyes RULE!
Mustang 86 - Mach1 Springs

stang&2Birds said:

You're into the TOLERANCES OF THE BLOCK, HEAD, PISTON, VALVES, GASKET, ETC at that point.

So, for SOME people, they will have enough clearance. OTHERS will not. Of course, that's assuming new valve springs. With old valve springs, then it's foolish either way.

IMHO, if you don't know, or have the tools/desire, to check for valve to piston clearance, then ASK yourself, is it REALLY worth that extra ~5HP in the mid/upper range? E7's loose some HP/torque from idle to ~1.5K verses the high swirl E6s.

The above is reality. I'm sure that you can find many posts that tell you otherwise.


If you want more HP in the upper range, then switch the intake and TB. Again, the '86 TB and upper are designed more for low-end to mid-range. The '87-93 upper and TB are a direct swap. IMHO, a pre-?98? Explorer is a better choice. The ?98+? intakes are better if you don't have to pass smog and don't need the EGR.

IMHO, I would not recommend notching the pistons while they are in the engine. It's nearly impossible to ensure that no metal fillings get into the rings. The stock 5.0 has low tension rings to begin with. So, it doesn't take much damage to have them start loosing compression.

Four Eyes RULE!
Mustang 86 - Mach1 Springs

Click to expand...

Thanks for the reply, i dont mean to hijack...
I have a 87-93 upper and lower sitting here. i guess i will keep the E7's around for something else. I know about the explorer intakes, as i have one on my 93 coupe (sig car) that is slightly ported.

i have 4 stangs in various stages, the 86 is a damn nice driver. 77k miles and i got it when it was STOCK.
the 93 coupe is my serious street car, it is torn down right now.
the 90 coupe (technically the ol lady's as her name is on the title) is a 4.6 2v swapper.
and the 94 GTS. rolling chassis, all there except engine, trans and related wireing. going to be a carb 351w, 6-speed, Cobra IRS toy. nothing more, will get beat everyday of it's life. And i mean beat! i have all the parts....

stang&2Birds said:

You're into the TOLERANCES OF THE BLOCK, HEAD, PISTON, VALVES, GASKET, ETC at that point.

So, for SOME people, they will have enough clearance. OTHERS will not. Of course, that's assuming new valve springs. With old valve springs, then it's foolish either way.

IMHO, if you don't know, or have the tools/desire, to check for valve to piston clearance, then ASK yourself, is it REALLY worth that extra ~5HP in the mid/upper range? E7's loose some HP/torque from idle to ~1.5K verses the high swirl E6s.

The above is reality. I'm sure that you can find many posts that tell you otherwise.


If you want more HP in the upper range, then switch the intake and TB. Again, the '86 TB and upper are designed more for low-end to mid-range. The '87-93 upper and TB are a direct swap. IMHO, a pre-?98? Explorer is a better choice. The ?98+? intakes are better if you don't have to pass smog and don't need the EGR.

IMHO, I would not recommend notching the pistons while they are in the engine. It's nearly impossible to ensure that no metal fillings get into the rings. The stock 5.0 has low tension rings to begin with. So, it doesn't take much damage to have them start loosing compression.

Four Eyes RULE!
Mustang 86 - Mach1 Springs

Click to expand...

Without flame, The guy is just going to use a set of stock E7's on his 86' block. PVC should not be an issue unlesss he swaps the stock HO cam out for a bigger one reguardless of springs, and, obviously, he would need to notch the pistons if a bigger cam was used. I stuck a set of ported E7's and an HO cam in a 87 vic motor and ran it for 2 years in a Ranger. I have a set of Thumper heads on my current 87' GT with supporting mods and have not regrets. Ford did not get rid of the E6 heads for no reason. If thats all I had and could afford, I would stick a rebuilt set of E7's on my 86' with a Cobra or GT40 upper and lower. Just me.

1987stangman said:

Without flame, The guy is just going to use a set of stock E7's on his 86' block. PVC should not be an issue unlesss he swaps the stock HO cam out for a bigger one reguardless of springs, and, obviously, he would need to notch the pistons if a bigger cam was used. I stuck a set of ported E7's and an HO cam in a 87 vic motor and ran it for 2 years in a Ranger. I have a set of Thumper heads on my current 87' GT with supporting mods and have not regrets. Ford did not get rid of the E6 heads for no reason. If thats all I had and could afford, I would stick a rebuilt set of E7's on my 86' with a Cobra or GT40 upper and lower. Just me.

Click to expand...

????
It's clear that you don't know about the unique features of the '86 Stangs.

MANY people that know how to do piston to valve clearance checking have done so over the years on E7s and '86 blocks.

MOST 100% stock E7 heads and 100% stock '86 blocks will NOT meet piston to valve clearance - period! This is OLD news (over 20 years OLD)! That's not to say that people don't still run the setups without checking. Plenty of foolish people out there! And, just because they don't meet spec, that doesn't mean that the valves will hit the pistons. There are many factors involved!

As for the reason for the '86 to '87 changes, that gets involved. Basically, quarter mile times sell performance cars, no one really gives a rat's *ss if the 1/8 mile time is better. Also, by then, Ford had plenty of data on the smog and POS idle of that Frankenstein setup that we know as the Stang GT 5.0 HO. So, Ford could go to the E7s that produce more smog at idle and do not idle as well. The E7's get ~5HP in the UPPER range and that head was already in production. But, the E7 heads REQUIRE notched pistons (which the '86 GT engines do not have).

Also, since quarter mile times sell performance cars, Ford did something that was VERY expensive and rather rare for a production car, Ford changed the upper for '87+ to get more mid/upper HP while sacrificing low end HP/Torque. That meant that the '86 upper is unique! That's a very expensive choice to make! Ford also used a bigger TB. But, the '87+ TB was basically shared with other engines. So, that wasn't as big of a cost hit.

In terms of today's dollars, the cost of Ford to change the upper was likely at least 5 million dollars. My guess is between $5 -$20+ million (in today's dollars).

Smog and idle where always issues for the 5.0 HO. (Although, the 94/95's where better since they had a better/faster EEC and algorithm.) That's why the '93 Cobra went to a milder cam - for idle reasons. IMHO, anyone that says that their 5.0 HO "idles well" is either on crack or a total fool. Or, maybe they live on an deserted island and the 5.0 HO is the only engine they ever seen or experienced? It's hard to think of any other production engine that has electronic fuel injection that idles as poorly as a 5.0. Heck, most carb setups even idle better!

Chrome_Rust said:

i dont mean to hijack...

Click to expand...

Pretty cut and dry question and answer to the original post. Not much really to discuss. And, the post is about E7 heads.
Cool selection of cars! When I got my '86, it was 100% stock and serviced only at the dealer - it even had the air silencer. It stayed 100% stock for only a few months after I got it.

As stang &2birds has said you will most likely end up with PTV issues just by changing to E7's let alone taking .030 off. Just because someone has done it does not mean it will work for you. How thick of a head gasket was used, the RPM the motor saw, the deck height of the block all play a part. The valves are set higher in the 86 heads so you are loosing that room and another .030 for your milling.

The bottom line is you have to check PTV and be prepared to cut the valve reliefs if necessary. Doing this on an assembled engine is not a big deal. Use duct tape to seal off the piston and just snug the head down with no gasket. It is adviseable to mask all cylinders in the bank before cutting so you don't knock chips into the adjacent cylinders when removing the head.

The trick to this is getting the tool. Isky rents them but they may not be in stock. There is another company that sells them but you are looking at $25 for the guide rod and $72 for each cutter.

http://www.etsupply.com/edgetools/index.html