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.
????
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!
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.