Heads question

Acid7711

Member
Sep 4, 2005
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TN
I've been trying to do some research on the heads and such but I still have a couple questions.

A friend of mine has a set of GT40 (NOT Gt40P) heads that he said he'd give to me for $200. Does this sound like a good deal? They are stock, come with stock valves and rockers still in place. I believe he said they came from a 95 Explorer, but I could be wrong. The questions I still are are as follows and are relevant to my 89 Mustang GT:

1.) What are these heads going to do for my compression? I'm running a KenneBell supercharger currently pushing only 6psi. Sometime later this summer I want to up it to around 8psi and if these lower my compression that would be just great! I'm just worried about the compression levels, and how safe this is going to be.

2.) Are the headgaskets used in each the same? I was looking at getting the headgasket kit from Stangnet that uses the headgaskets that are a tad thicker to lower the compression for supercharged engines. If I were to swap the Gt40 heads on, would you recommend I use a stock gasket, or use a thicker one to lower the compression?

3.) It won't be until the end of summer that I'm going to *possibly* upping the boost from 6 to 8 psi. If I swap on these heads, still running 6psi, am I going to see any kind of gain from doing this while still using the stock camshaft?

4.) My last question, I know my Gt40 lower intake manifold will match up to these Gt40 heads, however I also have FMS shorty headers on currently. I want to make sure that these headers will bolt up to the new Gt40 heads. Another concern of mine is what spark plugs to be using. Currently, I'm using stock plugs, just one range colder because of the supercharger.



Thanks so much for any insight on you shed on my questions. I'm in somewhat of a rush because I told him I'd find some answers out and get back to him because if I don't let him know in the next day or two, he's going to toss them to someone else. Thanks again :):SNSign:
 
$200 isn't a bad deal. I would get them checked and maybe freshened up. Your headers will be fine. I would get a good headgasket and headstuds for boost. As far as seeing power gains, you should. 2 more pounds of boost and a better flowing head than the E7. I would at least get a cheap off the shelf cam for around $150 new or a cheaper used one on Ebay.
 
1. Little to no change

2. Stock head gasket will do you just fine

3. You will definitely see a noticable upgrade with those heads over stock. i saw about 25hp at the wheels N/A when i swapped them on mine.

4. GT40 heads will accept stock style headers, you only have to worry about the P heads.
 
Constant 12V to ECU on pin 1

Ok. I am throwing a code 15 on my ECU which is the ECU memory code. I have been told on here by you guys before that either the ECU is not getting the constant 12V on pin 1 it requires or there is something bad with the ECU itself. This wire that goes to pin 1 on the ECU and carries this 12V where does it start? What does it connect to to get the constant 12V? I want to check it and make sure that it is connected but I don't know where to look. Thanks in advance for your help.
 
Thanks for all your help guys! I really apperciate it. I'm looking at an ecam and 1.7s to go allong with it. I figure even if I stick with 6psi for now, rockers, heads, and a cam will give me a noticeable gain.
 
yeah, I think nocticeable is a slight understatement...if you're going from stock to GT-40 heads, and stock to E cam (TFS stage 1 would be a good choice as well, blowers seem to like split patterns), then bumping up your lift with 1.7's...yeah, nice improvement with meager upgrades.

E cam + 1.7 rockers = 0.528" lift at valve...
 
Just what I wanted to hear. I hope I can get them, because it would pretty much finish off my engine mods once I got this done and I can move onto more of the appearance mods that I've been wanting to do. :)
 
Well, thanks for all your help anyways everyone. The guy turned out to be full of crap and I'm guessing he turned around and sold the heads to someone else. I wish people would adhere to some ethics now a days, but people seem to have forgotten their roots.

I guess it's no heads for me. Thanks anyways, at least I know for future reference.