Ok, clear this up for me.

bigjim240z

New Member
Aug 4, 2005
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I have an 86 mustang 5.0. Engine is pretty fresh and i dont wanna pull it back apart to swap out the pistons. What heads WONT have valve to piston problems? Will e7's make an improvment in hp over the stock 86 heads? Ive thought about gt-40's or world product cast iron heads. But im worried about the clearance issues. thanks for any help!
 
I dont beleive you would have problem with the E7's as long as they are not milled more than just a clean up. Yes they would help out on power over the 86 heads but most of the gains will be in higher rpm. If you knock out the thermactor bumps in the exhaust ports with a grinder they would be even better. I dont think your going to be able to run any head with a larger valve size though. It also depends a lot on the camshaft you run as well. As long as the stocker is in there I dont think you need to worry much on stock castings but I would still check the valve clearance before putting them on for good.
 
Check how much someone would charge you to notch reliefs in them. A local shop here in Va Beach only charges about $100 to notch them while the heads are off. Of course that means the car would have to be where he is at, unless you can coax someone into doing it at your house.... Well worth the $100 in my opinion. Then, you can plan on ANY head/cam combo you want.... E-7s will most likely work as well as the probablility of Trick Flow heads. Of course you aren't going to be able to take advantage of those heads without a cam change, which ain't gonna happen without notching, so it WILL still be your stopping point...

Jason