gt40heads what cam or stock cam

[bcstang]

doing a gt40 head swap.my question is for a cam .what is a good cam for this set up in a 5speed. or should i leave the stock cam in it? if i do a cam and lifter kit do i need to change the springs or rockers?just not sure .was wondering what some other peoples setups have done.

[upncomn94]

you will have to see what the gt40 heads are rated to in lift. not sure off hand. I have those heads with a tf stage one spring kit an e303 cam and 1.7 rr's. i have no trouble with that.

One budget way to go would be to get a set of 1.7 rr's and leave the stock cam. it will raise your lift about .30 and i believe that would make the stock cam in the .480-.490 lift. depends on the money you want to spend. whats your budget

[Freakingstang]

Potted Gt 40 heads with my own ported explorer intake I made 290/331 rw untuned with an Anderson blower cam (B21) long tubes and full bolt ons. It was one of my favorite budjet builds. It eventually went 12.0's at 111. When I had an e cam in it the best it went was 12.80's. Never had it dyno'd with that cam.

You will need different springs with a stiffer seat pressure for any aftermarket cam. I'd also highly recommend installing new springs regardless. You dint know how many miles are on them now.

The stock cam is a ok cam. It will have decent torque through the whole rpm range but will die off around 5k-5200. People will laugh, but the b303 cam works extremely well with the Gt 40 and Gt 40p heads

I have that AFM cam for sale if you are interested

[Neomustangs]

Theres a nice set of drop in springs for those heads, i think they were mentioned. Made by trickflow. I sold a person a set of shaved GT40 iron heads with 1.7 crane rockers here on this board. Sense he was running an aftermarket cam, he spent the extra money ($140.00 ithink??) and bought the springs for me to put in for him. Think he was very happy with it. Mustangmadman was his name here on the boards.

But anyways, definately do the springs if you go aftermarket cam. You can get away with the 1.7 RR and the stock cam for a nice budget rumble but anything higher you want springs. As mentioned already.

[95bstallion]

Crane 2031! It was designed for the GT40 3 bar heads and 1.7 rr. It has been proven to be a nice combo on many cars!

[upncomn94]

Theres a nice set of drop in springs for those heads, i think they were mentioned. Made by trickflow. I sold a person a set of shaved GT40 iron heads with 1.7 crane rockers here on this board. Sense he was running an aftermarket cam, he spent the extra money ($140.00 ithink??) and bought the springs for me to put in for him. Think he was very happy with it. Mustangmadman was his name here on the boards.

But anyways, definately do the springs if you go aftermarket cam. You can get away with the 1.7 RR and the stock cam for a nice budget rumble but anything higher you want springs. As mentioned already.


Those are the heads i have. i bought them off mustangmadman and then did some port work on the intake runners for my track heat intake. love the heads.

to the OP. just to give you an idea price wise. i spent roughly 800 on a cam lifters 1.7 rr's and the heads that already had the stiffer springs.

[bcstang]

cool ya i got the heads and i think i will get the 1.7rr's cause im on such a budget. i would have a nice e303 cam for it but i sold it to upncomin94 for his build, not thinking i would use it any time soon o well GIVE IT BACK:box: LOL just kidding. what kind of work am i looking at with the 1.7s am i re shimming and all that good stuff or are they bolt on.and the set i have came off a 93 lighting are they 1.6 or 1.7 in there stock i heard the cobras and lightnings had 1.7 stock is this true? i have till oct 9th too get this ready for the track so between work and the baby i should get it done.

[Night Mare]

I'm subscribing to this thread, because I'm going to do a similar build.

[boosted92]

I have gt40 aluminum heads ran steeda #17 cam and 1.7 roller rockers ran a 12.48 seemed a combo for me

[LX2NV]

i hate to admit, but again i'd suggest a "B" cam. B cam has a faint lope at idle and will pull straight through to 6500. the stocker and the "E" cam are dead in the water by 5200-5500. i would defiently do a spring upgrade. the "windsor upgrade kit" from trickflow is a decent "cheapy" kit. it comes with new springs, locks, retainers, shims, and a little mock up tool so people don't fu-bar the install too bad. while you have the springs out check the guides for wear and you could even use a solvent to check the valve sealing. i would run some roller rockers if you can afford to get your hands on a set. no need to swap lifters as they are a roller setup from the factory.

without extensive porting, a supporting exhaust, intake, etc. don't expect some of the times posted above..... but, you should have a good increase in the "seat of the pants feel" (+/- 40 rwhp) for a street car.

good luck.

[LX2NV]

:wave: ... just realized this was a ancient thread

[Freakingstang]

without extensive porting, a supporting exhaust, intake, etc. don't expect some of the times posted above..... but, you should have a good increase in the "seat of the pants feel" (+/- 40 rwhp) for a street car.

good luck.


Most Gt-40 headed setups will make between 250-270 RwHp and run 12.80's to 13.50's with a good driver and supporting mods (headers, Cam, intake, tb, cold air, gears, catback, etc. Weight of the car and auto/stick will determine the HP level, but bang for the buck, you cannot go wrong with a Gt 40 setup.

[LX2NV]

Most Gt-40 headed setups will make between 250-270 RwHp and run 12.80's to 13.50's with a good driver and supporting mods (headers, Cam, intake, tb, cold air, gears, catback, etc. Weight of the car and auto/stick will determine the HP level, but bang for the buck, you cannot go wrong with a Gt 40 setup.

agreed "03SVTSONICBLUE2NV" ....... did i say otherwise ? i know you got your "mystery :drama:" iron combo to run 12.0s but that's unrealistic for the average joe.

[bcstang]

thanks again for the inpu.t since i posted this thread i have put the heads and rockers on and solid eng mounts and i need the sping kit . im at a 13.25 with this but still reving out at 5200. thats all i can get out of the car .i am happy with the 1.666 60 foot time but no top end.hopfully a cam and spring kit this winter while she is tore down for paint.i then need to convert to mass air. man i got alot to do .

[BAM614]

Most Gt-40 headed setups will make between 250-270 RwHp and run 12.80's to 13.50's with a good driver and supporting mods (headers, Cam, intake, tb, cold air, gears, catback, etc. Weight of the car and auto/stick will determine the HP level, but bang for the buck, you cannot go wrong with a Gt 40 setup.

12.8-13.5 compared to what without it? Like high 13's/low 14's?

I'm just trying to compare and see what I can accomplish as I'm already at 12.9 w/ just gt40p heads, stock otherwise motor, can I see 12.0's or better like you did?

[Freakingstang]

thanks again for the inpu.t since i posted this thread i have put the heads and rockers on and solid eng mounts and i need the sping kit . im at a 13.25 with this but still reving out at 5200. thats all i can get out of the car .i am happy with the 1.666 60 foot time but no top end.hopfully a cam and spring kit this winter while she is tore down for paint.i then need to convert to mass air. man i got alot to do .

I'm assuming the stock cam? If you are dead set on the stock cam, you can retard it 4 degrees to gain 250-400 rpm. its gonna be close to 300rpm more than your peak now. IIRC

60' is reallly good for that time..what is your mph? I'd venture to say you are running out of rpm... what kind of gear is in the car and are you powershifting it?

[bcstang]

yes stock cam in there ,102.7 mph,it feels like im hitting a rev limiter at 5200.i heard it may be cause the springs, so definitely running out of rpm and there are 4;10 s in the rear. yes on the powershifting leaving at 5000 on slicks

[Freakingstang]

12.8-13.5 compared to what without it? Like high 13's/low 14's?

I'm just trying to compare and see what I can accomplish as I'm already at 12.9 w/ just gt40p heads, stock otherwise motor, can I see 12.0's or better like you did?


86-93 five liters ran 14.0-14.70 (stick/auto) at aroung 94-95 mph iirc (been too long)

your running a carb setup arent you? The explorer cam is designed for torque and quits making power about 4800rpm. (it was designed to move a 5K lb truck, not a 2500lb mustang). And the pistons are a tad different in the explorer reducing compression about a half a point. The gearing in the 4 cyl tranny is horrible for a V8, its almost like driving a dump truck, shifting every 15 feet...

Most cammed and ported GT-40 setups (P) or the old skool GT-40 iron heads make 280-320 RWHP and the Torque is what is killer on this little heads...

Now there have been a few, and I stress a few guys that have made just shy of 300 with P heads and some combination of cam and intakes. Carb'd setups are totally different...big cam, big carb, longtubes and spin it to make the high RPM power to keep it going.

On Average, the "quick" GT-40 setups are in the 12.20-12.50 range. Now what I mean is, that is about the fastest you are going to see with them. There have only been a handfull of guys that have gone 11's on GT-40 irons (NA, obviously) over the last decade.

The most impressive GT-40 combo I"ve seen with my own eyes was a buddy of mine who ran NMRA and FFW back in the day. 100% untouched P heads his combo went 11.37 at like 118ish. Now, I don't want to be decieving, because the bottom end was full of tricks and lots of weight taken out. he also spun it to 7800 IIRC.

My Combo was a junkyard build at first, and I worked it over about 4 different times. I bought the heads used from John Ericson in Avon. HE posted them on the Corral after upgrading his 94 or 05 cobra to better aluminum heads that I couldn't afford. The heads were ported by Jerry Wingard, the heads had EXTENSIVE work done to them, they also had larger valves installed and lots of unshrouding of the chamber.

When I first put it together, I ran an Ecam, with longtubes, an unported explorer intake, 70mm TB, 24lb injectors, C&L 76 MAF, 3.73's, 1.72 FMS rockers, Jet EEC chip, FMS RPM extender, etc. it had all the old skool bolt ons. BEST IT EVER WENT WITH THE E CAM was 12.83 @ 105 or 106. I raced it for almost two years like that.

I then bought a anderson blower cam bc I was going to install an old Paxton SN-95 blower. Ended up selling the blower and had already sold the Ecam. I installed the AFM B21 cam, and while the intake was off I ported the lower. First pass out it went 12.62 with a 1.72 60' I don't remember the mph off hand.

I thought there was more left in the intake, and extensively worked the GT40 style intake. Put it back on an ran it for almost a year. it went 12.50, and in cool air it went 12.48 as it best. The end of that summer (2003 iirc) went to a Mustang Life (forum before BuckeyeStangs) Dyno day at Bigshot Dyno in his old shop off of Chitteden rd. The car put down 289.9 RWhp and 330.9 RWTQ. (no tuning, just 3 pulls) The A/F was anyhere from 10.8 to 11.2. I remember Keith and his dad both asking what was done after the first pull, cause he just assumed it was going to make 250-260 based on the "gt-40" heads and the car looked like a heap, litterally. The next day, it went 12.48 @ 108.1- 108.8 with 60' in the 1.60-1.62 range at Dragway 42

The following weekend I changed out the 76mm C&L and 24lb injectors for a ProM 77mm and some 19 newer style explorer injectors. I also installed a 65mm TB bc another car I sold that week the guy wanted the 70mm. That weekend at Norwalk it went 12.22@ 109 as its best with a mid 1.6 60'.

For the next year it was a consistent 12. teens car. The best runs were 12.009, 12.01, 12.03 and all the hundreds up to 12.1. Highest mph was 111.9, but normally was in the 110.8 range. Best 60' was a 1.59. It was pretty consistent in the 1.600-1.61 range. I never had the car tuned, and kick myself in the ass for not, because I know it would have went 11's. I never had the car Dyno'd after the meter and injector swap. I know it would have broke 300RWHP. In all the track outings, we played with F/P and timing adjustments. The bitch loved timing, but the head gaskets did not, with 93.... she always ran the best right before one pop'd...I gave up on it that last summer in 04 when I pop'd 4 head gaskets and broke 5 T-5's

So, there you have it. 11's are possible, but its gonna take alot of time playing with the combo, alot of port work and a well thought out combo


My advice, Launch High, Shifter Higher and powershift like a mutha'

[BAM614]

I am running a carb setup...and with a 1.8 60' its went 12.9's at 106, so I'd say I've got a chance at 11's based on what you're saying.

I would venture to say your mustang was at least a few hundred, if not 500lbs heavier than my rx7, right? Mine weighs 2410 w/ 15 gallons in the tank.

I mean you were running the same mph as me w/ a ton more mods, and only a tenth faster. So I'd think my car will pick up quite a bit with a few good mods, and the ability to make power over 4500rpms...Plus I've still got a couple tenth to knock off in the 60' I hope. 1.87's aren't 1.60's....and isn't a rough rule of thumb 2 tenths in quarter for every tenth in 60'? That's nearly 3 tenths/half a second in the quarter, which would put me around 12.50's or so with good launch and shifts.

What RPM was that anderson cam good up til? I may look for one, I'd like to be able to spin it to 6500 or so because you're right I'm shifting like every second w/ the 4cyl t5....hell I was going through the traps in 5th gear....which can't be good for times.

[dr59l]

well i run a 306 gt40 combo witha afm pure street cam and carb set up running 7.21 w a 1.48 60ft in a coupe. im sure thats good to get in the mid 11s if i run the quarter. and that gt prob only weighed 3000 +/- thats what my 89 did NOT stripped and the coupes still got alot left in it if i can get it out the hole faster. damn radials!

[mustangsforlife]

trickflow stage 2

[The Don]

I am the current owner of Freaks heads that he was talking about and can attest to them being very good for iron heads. Those heads, 650 demon carb, air gap intake and small lunati cam in a 90 gt weighing about 3100 with me in it went 12.9s. Thats with an AOD and only 1.98 best 60ft. I am sure my combo will do low to mid 12s in my notch now and a 5spd.