I just recently purchased my 85GT from my father after totaling my 90GT. The car has 45,000 original miles and is the cleanest mustang I have ever saw. My question is would it be worth it to swap the heads off my 90 on to the 85. The heads on the 90 have minimum work done to them, just the thermactor bumps ground out and some trickflow springs and milled .012. I know the chambers are smaller and this was the reason the 87 and later had more compression than the 85 but is it worth the time and effort. My car has bbk headers and the usual exhaust (h-pipe, flows), it also has a 650 holley, 3.73's, and a whole list of the basic suspension parts and other small bolt ons. I am going to need to put new springs on the 85 heads any how and was wondering if there would be a noticable performance gain with the E7' heads.
head swap worth it or not????
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giddyup306
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- Oct 22, 2002
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Its really not that much work, plus these heads won't cost me anything. Also i would like to keep stock heads on the car because I want to see how fast i can go with the stock head and cam combo (hopefully mid 13's). plus this is an 85 GT and I don't want to start going radical for the sake of the car! Is there a difference between the 85 and 87-92 cams??
Killer50stang
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- May 11, 2004
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superstocker85 said:
Yes, you need to be careful when getting a cam. The 87-93 are Roller Motors and the clearance is different. Just make sure you tell whoever you purchase the cam from what year your car is. I had a problem with pushrods when summit sent me pushrods for a 79-86 stang and it came out very bad causing lots of damage because of the clearance. Anyway, don't waste your time switching those heads, you're not gonna notice if any difference. Save your time and money and get some good Alum heads! I'm running Edlebrock Performers, they rock!
dreddstang
Founding Member
I love the '85's! My second car was a black '85 T-top 5 speed!
Yeah, you may see a TINY bit of gain in that swap, but only that. The difference is going to be negligable. It would not be worth what you'd spend in time, effort, headbolts, and gaskets.
I had stock ported E-7's on my car for a while, it ran great! Have Twisted Wedge heads now and it's sooooo much better! As far as the thumper heads, I only know one person with that head/ intake combo, and they are not happy. This is not saying they are not a good part, there could be somthing else wrong with his motor, it's just that on the only car I have seen with that combo, he is putting like 215 to the wheels after spending his $$.
Get some aftermarket aluminum heads, if you really want to spend the time changing them. You can always keep your stock heads on the shelf if you ever want to put them back on so the car's correct!
I also agree with that you need to be careful picking a cam. Especially if you are changing heads, you have to make sure you have the right p to v clearance. I think the '85's were roller motors though, but pushrod length and p2v are always an issue when changing things around like that. Good luck, let us know what you decide on!
Yeah, you may see a TINY bit of gain in that swap, but only that. The difference is going to be negligable. It would not be worth what you'd spend in time, effort, headbolts, and gaskets.
I had stock ported E-7's on my car for a while, it ran great! Have Twisted Wedge heads now and it's sooooo much better! As far as the thumper heads, I only know one person with that head/ intake combo, and they are not happy. This is not saying they are not a good part, there could be somthing else wrong with his motor, it's just that on the only car I have seen with that combo, he is putting like 215 to the wheels after spending his $$.
Get some aftermarket aluminum heads, if you really want to spend the time changing them. You can always keep your stock heads on the shelf if you ever want to put them back on so the car's correct!
I also agree with that you need to be careful picking a cam. Especially if you are changing heads, you have to make sure you have the right p to v clearance. I think the '85's were roller motors though, but pushrod length and p2v are always an issue when changing things around like that. Good luck, let us know what you decide on!
04sleeper
Founding Member
85's have roller moters. The pushrods are the same. 84's are the last year for non-roller cams.Killer50stang said:Yes, you need to be careful when getting a cam. The 87-93 are Roller Motors and the clearance is different. Just make sure you tell whoever you purchase the cam from what year your car is. I had a problem with pushrods when summit sent me pushrods for a 79-86 stang and it came out very bad causing lots of damage because of the clearance. Anyway, don't waste your time switching those heads, you're not gonna notice if any difference. Save your time and money and get some good Alum heads! I'm running Edlebrock Performers, they rock!
I say switch them and you will definatly get more power fom them. Especially having the exaust bumps ground down and all.
moonenn3186
Founding Member
Just to make sure everyone is clear here:
Not all 85's were roller engines. Only the GT's had them, and then only if it was a factory 5 speed, 4v Holley car. You will find out by pulling the intake for the head swap. As far as a performance gain with E7's . . . you would probably never notice. Otherwise the pushrods should be very close to the same length . . . you may want to check if you do it - since your heads were milled down. . . If you got some extra time, and some extra gaskets . . .go for it and let us know!
Not all 85's were roller engines. Only the GT's had them, and then only if it was a factory 5 speed, 4v Holley car. You will find out by pulling the intake for the head swap. As far as a performance gain with E7's . . . you would probably never notice. Otherwise the pushrods should be very close to the same length . . . you may want to check if you do it - since your heads were milled down. . . If you got some extra time, and some extra gaskets . . .go for it and let us know!
the car is an original holley 4 barrel car and it is the first year for the roller cam and the pushrods are the same length as the 87-92 motors. What valve springs should I install on the stock cam to get some more RPM's out of her?? Because both heads need new springs, because the ones on the E7's were the trick flow upgrade springs with 110#'s of closed seat pressure and I don't know if those were meant for roller cams. They did work decent on my 90 GT so I don't know?
