Cam/rocker options

ctrout71

Member
Feb 2, 2010
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I've got a set of '93 Cobra heads that I'm really itching to slap on my '95 vert but I have some decisions to make. The heads need rockers so should I get 1.7s, 1.6s, or 1.72s and stick with the stock cam or should I get a cam and just transfer the stock rockers from my E7s over to the GT40s? I guess as a final option, I could do cam and rockers but that's all the work of doing the cam swap plus double the expense of just rockers with stock cam. I'm on a budget build so what do you all think is the best bang for my buck? In the end, I think I will end up with shorties, catted x-pipe and either Flowmaster, Borla, or Mac cat-back. Intake will be Explorer GT40 style and someday maybe a Kenne Bell. I'll also be doing a gear swap to 3.73s soon.
 
Since you stress a tight budget .........
Just use your original stuff :)

More cams are cut for the 1.6 ratio anyway ;)

Besides ... rr's only yield 5 to 10 rwhp and I'd bet the gain is closer
to 5 than 10 :(

Therefore ... as you said ... NOT a good bang for the buck spent :bang:

Again ... with the budget in mind ........

If you go to a different cam .....

You want to keep your choice limited to very mild and try to get by without
the need for a custom tune cause the cam made the pcm go nuts :crazy:

Grady
 
I don't mind tuning issues because the car is already equipped with a Tweecer. My real concern is if I use my stock cam and rockers, am I leaving a lot of power on the table? If 1.7 or 1.72 rockers will work with my stock cam and gain me 10 HP or so, I don't mind spending that money since I have to do the work of installing rockers to use these heads anyway. A cam would cost quite a bit more than the rockers would and would also be a lot more work so I would really need to see a lot more power gains to make it worth my while. Now if it gets me 50hp or so with my stock rockers, I would definitely be willing to spend the money and time to do it. If the cam and 1.7 or 1.72 rockers get me 70 HP, I would buy both. But if a cam is only good for 15 HP by itself and only 25 HP with rockers and those rockers are worth 7 HP by themselves, I probably wouldn't spend the coin on either one. I guess I could get more specific in my questions then.

1. With GT40 heads and Explorer intake, what kind of HP gain would I see from 1.7 rockers alone with the stock cam?

2. With GT40 heads and Explorer intake, what kind of HP gain would I see from 1.72 rockers alone with the stock cam?

3. With GT40 heads and Explorer intake, what kind of HP gain would I see from 1.7 rockers in combination with a TFS1 cam?

4. With GT40 heads and Explorer intake, what kind of HP gain would I see from 1.72 rockers in combination with a TFS1 cam?

5. With GT40 heads and Explorer intake, what kind of HP gain would I see from stock rockers in combination with a TFS1 cam?
 
I don't mind tuning issues because the car is already equipped with a Tweecer. My real concern is if I use my stock cam and rockers, am I leaving a lot of power on the table? If 1.7 or 1.72 rockers will work with my stock cam and gain me 10 HP or so, I don't mind spending that money since I have to do the work of installing rockers to use these heads anyway. A cam would cost quite a bit more than the rockers would and would also be a lot more work so I would really need to see a lot more power gains to make it worth my while. Now if it gets me 50hp or so with my stock rockers, I would definitely be willing to spend the money and time to do it. If the cam and 1.7 or 1.72 rockers get me 70 HP, I would buy both. But if a cam is only good for 15 HP by itself and only 25 HP with rockers and those rockers are worth 7 HP by themselves, I probably wouldn't spend the coin on either one. I guess I could get more specific in my questions then.

1. With GT40 heads and Explorer intake, what kind of HP gain would I see from 1.7 rockers alone with the stock cam?

2. With GT40 heads and Explorer intake, what kind of HP gain would I see from 1.72 rockers alone with the stock cam?

3. With GT40 heads and Explorer intake, what kind of HP gain would I see from 1.7 rockers in combination with a TFS1 cam?

4. With GT40 heads and Explorer intake, what kind of HP gain would I see from 1.72 rockers in combination with a TFS1 cam?

5. With GT40 heads and Explorer intake, what kind of HP gain would I see from stock rockers in combination with a TFS1 cam?

Honestly ... roller rocker gain over the OEM steel stamped rockers is
gonna be teeny tiny :(

Even with the larger ratio ... I'd still hold to like close to 5 rwhp

1 and 2 would have to be close to like the OEM Cobra with a bit less

3 and 4 would be like around 15 more

5 would be like 3 & 4 with around 5 rwhp less

Just look at the OEM 94-95 Cobra

It has got
GT 40 heads
Cobra intake
I think larger 65 mm tb

If there is more stuff I forgot ... Someone let me know
but
When you use all that OEM stuff ... You basically are building a Cobra ;)

Grady
 
So it sounds like if I'm going to spend any money at all, I should just go all the way and do cam and rockers and I'll probably only gain about 15hp in doing so. I just don't think I want to spend the $500ish and do all that work for that relatively small gain. I think I'll just do the heads and intake which I already have and then gears and a full exhaust later when I have more funds. After that, I'll just save for the Kenne Bell and be done. Thanks so much for the input.
 
So it sounds like if I'm going to spend any money at all, I should just go all the way and do cam and rockers and I'll probably only gain about 15hp in doing so. I just don't think I want to spend the $500ish and do all that work for that relatively small gain. I think I'll just do the heads and intake which I already have and then gears and a full exhaust later when I have more funds. After that, I'll just save for the Kenne Bell and be done. Thanks so much for the input.

I got data about OEM combos showing what they did at the dyno :)

It was up here forever but my host site went belly up :(

I'll try to get it hosted a bit later this afternoon after I find the file

You can see what others have been able to accomplish that have built
combos simular to what you speak about here

Grady
 
Some stuff I found from various places :D

I have no way to know the type of calibration these were done with :shrug:

It is most likely a mix of STD and SAE :(

Same kind of thing for type of dyno :shrug:

Could be a mix of Dynojet and Mustang :(

Never the less ... You can get a ball park idea

Grady

iron_only.webp
 
Thanks very much for posting that. It is very helpful. It looks like the GT cam may be better in combination with the GT40s and Explorer intake than the Cobra cam.