92GreyGT

I don't have a 4.6 but a good friend of mine does and he has a problem that I thought maybe someone on here has had and knows how to correct. He has a 99 GT with around 100,000 miles on it. He bought the car about six months ago it has a full Bassani exhaust with mid length headers, off road X pipe, and Bassani mufflers that sound awesome. He hasa Dragon intake plenum, JLTcold air,75 mm throttle body, and a C&L mass air meter (not sure of the size).Anyway he was crusing around this afternoon and one of thespark plugs blew out of the head. When he got the car he did a tune up and he and I areboth older and this is nothis first hot rod or Mustang soI know the plugs were put in tightly. He put a new plug back in and the threads are fine and there is no heli-coil in the head. Has this ever happened to anyone on here? What could have caused it? He doesn't have a blower or nitrous, it's N/A. I have to admit the car has suprised the hell out of me. He only has a 3.73 and is running 8.20s @ 84 mphin the eighth mile.Also we just ran our cars at Virginia Motorsports Park and his car is laying down on the big end. His eighth mile times were what was above but his quarter was 13.10s at 100. I thought he should have been in the 12s myself. The car weighed 3440 with him in it. Thanks in advance for your help.

contentsunderpressur

That's a common problem. The plugs need to be tightened to factory specs to make sure they don't loosen up and blow out again. BTW, what is your 60 ft? A 7.58 at 90 mph means you've got a very very nasty 60 ft.

92GreyGT

If the track is there on drag radials I have high 1.50s. When the track is carpyI am in the low 1.60s. UPR suspension is worth every penny!

92GreyGT

Thanks,so this is not a uncommon thing? He will be releived. The thought of taking the engine out again would kill him.500 rwhp with 281 cubic inch, that is what is impressive! I am sort of an old school pushrod man, but you have got to give credit where credit is due. There 4.6s are impressive. My friends car has impressed me very much. He is running Weld Draglites and M/T ET streets and has 60's in the low 1.70s with a Saleen suspension. I know they could be better with a drag suspension, but they are not bad.

72MachOne99GT

It's only a matter of time before it happens again.

My car blew a plug *#3 pass. side* and it took the next one fine.

One day i took it out to check the plug, and the threads stripped the rest of the way out when i tried to put it back in, and it wouldnt take a plug at all.

I had to do the helicoil thing, with no issues as of yet.

contentsunderpressur

Thanks, it took 11 lbs of boost and a 75 shot but I got there. I'll be going back in a bit to get the flooding problem fixed and hit the 550 mark. Can you give me a link to where you bought your suspension from? That's my problem now. I run a 7.59 the other weekend at 97.6 mph. I know it'll run much better times if I can get the 60 ft down.

92GreyGT

http://www.uprproducts.com/shopping/...ear+Suspension

They are great to work with, never had a minutes trouble with anything and the price is right. 97 mph in the eighth? That is solid low 7s high 6s. My car does it's damage out of the gate. Too bad you don't live closer, I part time at a race car shop and that is where I set my suspension up. We scaled the car out to get the correct preload and weight balance. I don't even run drag launch springs, I have Eibach Pro lowering springs. I do use Strange struts, Lakewood shocks, UPR Pro Seriesadjustable uppers and lowers, and I moved my battery to the rear. When I moved my battery that put me over the hump and got me into the 1.50 something 60' range. I got a great picture of my car at a local eighth mile track that wasn't even hooking good, the tires aren't even wrinkled, but both front tires are in the air. I will talk real sweet to my wife and see if she will take it to work and scan it, it's like 13x20 and my scanner at home isn't big enough.I she will I will post it and let you know.Good luck and thanks!

contentsunderpressur

Hmm, I have strange adjustable shocks and struts, sub frame connectors, tubular lower control arms and adjustable upper control arms. I haven't set my pinion angle yet and just installed the sub frames last week so I haven't got to run it yet. What did you set your pinion angle at? I hear that's the ticket but sounds like you had better luck from moving the battery back?

1hotdrp

i just had a plug blow out on mine 2. only stripped the very first thread but ive been hearing its only a matter of time b4 it happens again...

92GreyGT

3 degrees is what I set mine at. I am buying some QA1 adjustable rear shocks this week. Yes moving the battery back made a difference.

I told my friend that he's not the only one with this problem. He's going to keep a close check on them. Thanks for all of your guys help!