What cam for a mostly stock stang with gt-40/p heads.

[bjl95mustang]

I'm looking at swapping in a cam and heads this summer. I was looking at getting a set of gt-40/p heads. How are the b/e303 cams? I just want to pick up some power but I dont want to go to radical on the cam. What power gains am i looking to get with this setup? Are there any down sides to these cam's? Would you recomend another cam?

Thanks,
Brandon

 

[TMC]

Stick with the stock cam with that aod and small converter and your ride will run much better than with the b/e and most other cams out there.

 

[Joes95GT]

Maybe put a 1.7 rocker on the exhaust side to help the sorry exhaust ports of the P heads a little? I don't know how much it would help being that the P's don't flow much more past .450" lift.

Joe

 

[bjl95mustang]

How much potential hp will I be giving up by using the stock cam?

 

[TMC]

The question is really - How much potential acceleration will you be giving up by using an aftermarket cam?

The Stock cam will be faster with your current mods. The aftermarket cam may see 12-15 HP more than the stock one at the peak but your car will run faster with the stock one because there will be more power under the curve.

 

[tmoss]

I just dynoed my stock 193,000 mile short block with TMC's old F/S heads and my stock cam installed at a 108.5* ICL with an Explorer intake with mildly ported lower, Explorer 65mm TB and Explorer 19# injectors. Power was right where I thought it would be (260-270) @ 257RWHP SAE but the torque was excellent - started at 270RWTQ @ 2,000 rpm, peaked @ 309RWTQ and averaged 284 SAE RWTQ across the 2,000-5,600 rpm band. This is a speed density car and the EEC took to the new combo like I never changed a thing. A/F ratio was lean, so there may be a few HP left in it as-is.

Take a look Troy................

http://gallery.stangnet.net/data/500/17697tmoss_dyno2.jpg

 

[TMC]

Hey Tom,

You made some pretty good numbers for an old motor. The HP/TQ curves look very nice like the motor is still happy too.

Not that I’m disappointed with the numbers you made, but I think your car has more in it that could be found pretty easily. It looks like the motor is too lean from around 4k-5k RPM’s as you mentioned. Judging from the graph it looks to me like you stand to gain some power in the 4500-5200 RPM range with a little more fuel there, say ~10-15 HP with the proper fuel/timing. I’m not certain if you have an adjustable FPR but I’d consider that a requirement with your SD combo.

Where did you set the timing?

With it so lean I would go crazy with timing just until you get more fuel into it. For reference, I used 38° total when we had a stock shortblock with 100 octane-unleaded fuel. With pump gas we didn’t notice any difference in performance. The A/F was around 13:1 I think. I would think with the right amount of fuel in your motor it would like to be in the 34-36 total timing range.

I’ve got a dyno sheet at home from when we had the stock shortblock and those heads before the prep work that I’ll try to remember to post later this week if you like. I think we made 281 rwhp and 300 rwtq at the time NMRA legal. But, that was after a good amount of effort was put into making the car work as well as possible with that combo. I’m certain that when we first put it together it was more like ~250 hp and ~285 tq so I don’t think your really off from where you should be right now.

Email me if you like at [email protected] and I’ll answer any questions you may have.

Good luck!

 

[tmoss]

Yeah, I was pretty happy with the results for ZERO tuning. I already set the fuel pressure up from the 39# dyno number to 42#. Timing was set to 13* intitial during the dyno. My compression averages (9.4-9.6 variances) just a tad under 9.5:1 based on measured deck heights and all. I'll look into total timing and check it. I'd appreciate a look at that dyno sheet. Thanks for your help and input!