what size lift are cast iron gt40 heads???? i'm trying to decide on a cam....i had a 92 gt with an e303 cam....but am thinking bigger does anyone have any suggestions???
question about gt40 heads.........
- Thread starter MI95Cobra
- Start date
blksn955.o
Founding Member
I did alot of research on what cam the gt40 heads tend to like.
I found that the gt40 heads like a split patt. cam (diff. int. and exh. numbers) that are larger on the exh. side. They like lift to be around the .500 mark again with a larger number on the exh. The heads also like a split in the dur. of the cam in +8 or so in favor of the exh.
so something in the range of .490-.500 int. and .500-510 exh. with 6-8 more dur. over the int.
I found that the gt40 heads like a split patt. cam (diff. int. and exh. numbers) that are larger on the exh. side. They like lift to be around the .500 mark again with a larger number on the exh. The heads also like a split in the dur. of the cam in +8 or so in favor of the exh.
so something in the range of .490-.500 int. and .500-510 exh. with 6-8 more dur. over the int.
yeah i was thinking either a f303 cam or a trick flow camshaft with a lift of .499 and .510...what do you think???
yeah im thinking of af303 cam or a trick flow stage 1 cam with a lift of .499 and .510...what do you think????
blksn955.o
Founding Member
I went with the tfs1 cam back when they were really not used yet too much here. Its alright it gave my gt a few issues but nothing major. The cobra eec is better at taking to mods though...but that is more on the tuneing side like with a tweecer.
The letter cams are really not the best choice, they are old and give us 94-95ers the most issues. That does not mean people do not still get good results every once and awhile though.
If you want the fewest issues and less hassle with an off the shelf cam go the Steeda 19.
I would put the tfs1 second since it was not designed special for the 94-95 like the 19 cam. The issues I had were rich idle that would cause cold start issues liike a stalling issues when it was cold out at first startup. Every once and a blue moon it would stall at a stop (only like 3-4 times maybe).
With box stock 95 cobra heads and a ported stock gt lower and the tfs1 cam untuned I went 13.5 @ 102 with a bad 2.4 60ft.
The letter cams are really not the best choice, they are old and give us 94-95ers the most issues. That does not mean people do not still get good results every once and awhile though.
If you want the fewest issues and less hassle with an off the shelf cam go the Steeda 19.
I would put the tfs1 second since it was not designed special for the 94-95 like the 19 cam. The issues I had were rich idle that would cause cold start issues liike a stalling issues when it was cold out at first startup. Every once and a blue moon it would stall at a stop (only like 3-4 times maybe).
With box stock 95 cobra heads and a ported stock gt lower and the tfs1 cam untuned I went 13.5 @ 102 with a bad 2.4 60ft.
You can find the Steeda #19 cam at www.steeda.com. You should keep in mind that more lift isn't always the answer to more power, and that lift, duration, and overlap all play a vital role in what makes your cam work well with your combination. The GT40 heads will probably perform better with a cam that favors the exhaust as blksn955.o pointed out. The specs on the Steeda 19 cam with 1.6 rocker arms are:
Intake:
lift: .480
duration: 220° (at .050 lift)
Exhaust:
lift: .480
duration: 226° (at .050 lift)
This cam also has a 115° lobe separation and is emissions legal.
As you can see, this is a split pattern cam favoring the exhaust, and would probably net you some pretty good performance on the GT40 heads, without freaking the computer out. If you wanted more lift, you could add 1.7 rockers to bring the lift to .510.
Intake:
lift: .480
duration: 220° (at .050 lift)
Exhaust:
lift: .480
duration: 226° (at .050 lift)
This cam also has a 115° lobe separation and is emissions legal.
As you can see, this is a split pattern cam favoring the exhaust, and would probably net you some pretty good performance on the GT40 heads, without freaking the computer out. If you wanted more lift, you could add 1.7 rockers to bring the lift to .510.
ok....thanks for your help....i had an e303 cam in my modified 92 gt.....it sounded and ran great....
reddy351
10 Year Member
Ok. I assume that the specs you gave were for unported heads. I have "gasket matched" mine. Do the Gt40's like the .490-.500 lift and split duration if the exhaust ports are opened up to the gasket size? I would think that the duration should be the same, if the exhaust ports are improved.
JOEGTS
New Member
I have the Steeda 19 and my car will not idle with it when it gets hot. If I had to do it all over again I probably would have gone with the Crane 2031. It is much better priced than the 19 and you can get it with the springs for almost the same as I paid just for the cam.
legalize420
Active Member
blksn955.o
Founding Member
wow thanks for all the help...i think i'll either go back with an e303 cam or even the f303.....i can get an e303 cam and the f303 for around $170 new....it'll be a close
desicion....
desicion....
