The background: The history of the heads is soft of a mystery. We believed they were stock heads that had a valve job, with no machining....the surface was just cleaned up. Then I had those heads "street ported" by Mustang Specialties, where they ported them and took 30 thousands off the surface. The lower intake is an Edelbrock performer, used but in very clean condition. It only had a few thousand miles on it. I know, used parts cause problems. The problem is the intake will not line up with the heads. The heads are on and torqued down, when we put the lower intake on, the bolt holes would not line up perfectly. None of the bolts would thread on, so we looked at the intake and noticed that each side of the intake needed to come closer to the head. Obviously that is impossible, so we figured the heads had been machined down more than we originally thought. So we widened the holes in the intake a little so the bolts would bolt onto the head. The intake would also not just sit on the heads and block. You should normally be able to just lay the lower intake on the long block straight, even with the valve covers on. But with this one we needed to remove the valve covers and still we had to lower the intake down one side at a time. So we removed a very small amount of the side edges of the intake so it would lay straight on the longblock. Once we got the intake to bolt on we noticed two things wrong. The flat part of the block, where it meets the flat part of the intake on either end, had too much of a gap. With a thick silicone bead and the intake bolted down, it would not push out any silicone. The other thing was the intake runners would not line up perfectly. You could look down the runner and see a "drop off" into the chamber in the head...where they should line up perfectly. We are thinking that the heads have been machined down further than we originally thought, because 30 thousands shouldn't cause an issue like this, right? So I am taking the intake down to a machine shop tomorrow to see if they can machine the intake to fit with machined heads. The problem is we don't know exactly how off the heads are. Without removing the heads again and matching them up to uncut stock heads. Then after we solve this issue, I don't know what kind of a problem I will run into with my 1.7, bolt-down, rockers. We think those might need to be shimmed because if the heads are that machined, and the rockers are just bolted down, it might be causing the valve to stay open a little bit. I just wanted to run this by everyone and get some other thoughts and opinions. I know I should have started off with NEW stuff, but I figured the intake was used but it's not like it can be "bad"...and we were VERY sure that the heads had never been machined any more than a light resurfacing. And Mustang Specialties is a VERY reputable machine shop who ports heads all the time with no problems.
Sounds like those heads must have been milled pretty drastically. I just dropped a set of Powerheads (which are milled .040") on my car, and my gt40 lower bolted right on. The end gaps were pretty big though. I ended up using the cork gaskets and a bunch of rtv (sort of made a sandwich).. hand tightened the lower bolts, let it sit for an hour then torqued it to specs.
def sounds like to much came off the heads.which as ya know is not a good thing.ya might want to think about this before ya try to machine your intake to fit. [if ya machine your intake] 1.ya will have to shim the rockers(allmost def) 2if the heads ever need to be resurfaced again? 3pist to valve clerance 4possible vac leaks around the intake 5destroying a perfictally good intake(meaning its useless on any thing else) 6price for the machine job on the intake. i would say you might be better off buying another set of heads. perhaps some thumper heads their fairly cheap and work quit well from what ive read and heard about them
Ditto the above, dump the heads because you are only asking for trouble on everything else from valve train to exhaust fitment. Friend went through this nightmare last year, got frustrated after ruinning an intake and still not getting it to run. Jamie
Yea, that is what I am thinking. If I machine the intake...and it doesn't work, because I really don't know how far it would need to be machined...then I am out an intake AND heads. Looks like it will be down another few weeks while I search for heads. I am going to check Thumper's prices.
Measure form the lower head bolt boss to the deck of the head.. stock is about 1.385 !! cut .030 should be about 1.355 cool?? there are a lot of variables but that should help you see what is cut off!! Also check the intake and see if the intake is matched to the SAME gasket the shop used!! I use the comon Felpro 1250!! Cool?? Just me......................... Thumper
Funny you say that, I was about to ask for a stock measurement for me to compare to. I used the two holes on both ends of the head for a measurement, the ones you use to mount the accessory brackets. I used the bottom hole and measured from the bottom of the lip to the bottom of the head. I didn't have any new stock heads to measure, so I measured some used stock heads. One of those sets being the stock ones that were on my car. The measurements went like this... Heads #1: .31 and .29 Heads #2: .27 and .28 My old stock heads: .29 and .30 The ported heads looked like this.. .18 and .23 So not only is there a matter of too much milling, one head is much worse than the other. I don't know exactly what stock should be, and I assume the differences in the stock heads I measured could be attributed to slight rust, and any other possible debris. However, even though the other stock heads varied, they didn't seem to vary too much. Not like the ported heads I have on the car. I am going to measure from the bolt boss like you suggested, now that I know what a stock head should measure out at. Thank you.
