Explorer GT40 Heads/Intake

[Nevz86GT]

I think I made a decent score today with the purchase of an Explorer upper/lower and a set of GT40 heads off of a 1996 Explorer for $200. The motor "allegedly" only had 86k miles on it. My questions are related to the heads. They are in obvious need of a good cleaning and inspection.

1) I am not knowledgeable when it comes to the parts of a cylinder head and I am wondering what types of things you guys think that I can expect to have to repair or replace when I bring these to the machine shop? I am hoping that I won't have to invest any more than say $300 to get the heads in good running order.

2) Will I be able to use my old pushrods/rockers off of my E6's with these heads?

3) Will I be able to use my stock valve covers with these heads?

4) Any ideas on what kind of money these machine shops might be looking for to "freshen" these heads up?

I will be putting these onto my stock '86 shortblock and I am planning on having the pistons flycut when I get them installed. I apologize in advance if any of my questions are stupid but I am a relative nooby when it comes to auto mechanics. Thanks in advance.

Jonathan

[rsw007]

1 upgrade springs.
2 yes but good time for some 1.7 rockers " ptv clearance"
3 yes
4 250-350 plus 150 for stronger springs. 125lb seat with .550 lift is a good spec spring for them.

i run gt-40 heads and explorer intake with b-303 cam and 1.72 rockers on my 91gt.

[AaronATX]

New valve springs are a MUST with those heads. It will run without them, but when you wind it up to 5000+ it will sound like your valvetrain is going to explode ;p

Get a valvejob and some k-liners (cheap valvestem guides), and new valve stem seals. Also have the machine shop check the head to make sure it is true (flat, not warped) all that plus installing the valvesprings (which you can do if it will save you money, its not hard) should be less than $300 at the machine shop. And if you can afford it find out how much they will charge to bake the heads to make them clean like they are new. ($30 to $50 usually) add a few bucks for new freeze plugs also.

I forget, but I think the 96 explorer setup has the internal thermactor/egr stuff, so it should all bolt right up. If you are lucky you got a lower intake that already has the ACT bung in the right place. Otherwise you'll need to drill/tap a hole for that sensor. There are alot of writeups on that, its pretty easy stuff too.

I believe you will need to switch your fuel lines over from the stock intake as well.

I had an explorer setup a few years back, ran well for the price.

Personally if money is tight I wouldnt really worry about the rocker arms. The money would be better spent on freshening the head to like new condition.

Stock valve covers will work no problem. ( and if you do get rockers with stock valve covers make SURE you clearance the baffle under the oil fill cap, otherwise the motor will do it for you...not good)

Oh, and DO NOT reuse the old head bolts. You will need new ones at the very least, and you can't go wrong with arp studs (which are reusable)

[burntorange84]

Your E6 valve springs and valve train will be fine on a stock cam. I'm in the middle of freshening up my own Gt-40's (non-P) right now; I'm using the springs off the E7's I have. Check the combustion chamber volumes, Explorer heads are higher, about 65 cc's I believe and you'll have to figure in all volume from the reliefs cut in the pistons.
Check your lifter preloads when swapping the heads,shims will probably be necessary. I made an assumption when I swapped E7's and I collapsed two lifters.

-j

[AaronATX]

I knew i'd seen an orange 84 around austin!

*edit* I R can speel.

[burntorange84]

Yep, I live North and my copper stang has been up on stands for the last 4 months
-j

[AaronATX]

Sounds like you got it handled ~ pm me if you need anything, I recently finished the block and head class at the school of automotive engineering in houston ~ I should be able to help.

[keithnra]

i used stock springs on a stock cam and it works just fine

[Nevz86GT]

i used stock springs on a stock cam and it works just fine

Are you referring to the stock Explorer springs or the ones you took off of the heads that you replaced?

In this case I would be replacing E6's with 125k on them. If I could get away with using the E6 springs I would be pleased.

I am praying that I will have sufficient ptv clearance running these GT40 heads with 1.6 rr and the stock HO cam (remember I have forged flat top pistons with no reliefs). I will have to mock it up and see what happens.

I am concerned about getting so much money in these heads that I could have bought a decent set of used aluminum heads.

The money is adding up quickly:
Machine work ??? 250-350
TFS Spring Kit 150
Proform 66879 1.6 RR 175
Cost of heads 100

It looks like I will be at 600-700 easy (just the heads) when its all said and done.

Knocking off the 150 for the springs would be nice.

I don't know if using my E6 stamped rockers would be a good idea or not because I have no idea if they are worn out or even really 1.6 ratio (I have read they can be 1.4 or so).

When I take into consideration the expense of notching the pistons as well I am really getting nervous.

[bwguardian]

If worried about monies right off...leave the stamped rockers on for now, that is an easy fix later if really desired. You may even find after your mock up for ptv clearance that you can utilize 1.7 ratio rocker arms.

[Nevz86GT]

I appreciate everyones input on this subject.

I found a statement that a guy made on another site that gave me some hope regarding the ptv issue. He said "Listen to me a second! First ,I would like to state that I have personally pulled my stock '86 5.0L motor and gave the short block to my brother in CT. I then contacted Air Flow Research about my concerns on the flat top piston issue on the year block. The tech. guy told me that they put 165 AFRs on that motor with a Comp. Cam # FW XE270-HR specs.= 270/276 dur. & 218/224 dur. @ .050 and .512/.512 lift with a lobe center of 114 degrees all day long ,with "NO" problems on the clearances!! I added the 1.6 rollers on that motor plus a stealth intake and a 650 holley double pumper. I also gave him my T-5 for his 86 Gt project. Anyway, The motor"ROCKS!" No problems with the clearance issues!! So if you still don't believe me,just call up Air Flow Research ask your self. You will not be disappointed. Your best source of info is the manufacture period!!! I would not mislead anyone on this,cause I know how hard we all work for our $$$$".

Based on what this guy is saying and this information on the stock '86 HO cam I may be in business:
1985-1988 5.0L Mustang Roller Cam
Part # E5ZE-6250-AA
Advertised Duration: 266 / 266
Duration @ .050: 210 / 210
Lift w 1.6 rocker: 0.444 / 0.444
Lift w 1.7 rocker: 0.472 / 0.472
Lobe separation: 115

I am going to call around to some local machine shops (North Georgia) and see about bringing the heads in to be checked out early next week. I will keep you guys posted on the progress.

Thanks again!

[rsw007]

ptv issues ussually arise from duration not lift.

[AaronATX]

seconded! rsw007 is 100% correct