Performance??

[stirling33]

I apologize in advance for the long winded thread but I need some help,

I recently installed a set of GT40 Aluminum Y303 heads and a Ford racing cam -Duration 290/ 300, Lift .472/ .496. The rest of my set up is as follows :
stock block from a 88', RPM intake, Holley 600 carb,Hooker headers, Flowmaster 40 Series Delta Flow Mufflers, and a 3:89 gear.

My question is that I have seemed to have lost that initial torque out of the gate and I am wondering if I have made a bad cam choice. I just had everything dyno tuned so all the carb jetting is right on and everything has been adjusted and it runs smooth, but is seems like it takes to long to start pulling. Could it be I need a bigger carburetor or a smaller cam, this is not a monster street set up I know but it seems to be under performing.

 

[302 coupe]

bad cam choice IMO. Way too much duration, that shifts your power curve way up in the rpms. You need less duration and more lift to get the torque to come in lower, while still keeping the horspower in the upper rpms.

If you have an auto trans, put at least a 2400 stall converter in there.

 

[12sec67]

vote # 2 on the stall converter!

also... then what did you dyno and what was the fuel curve A/F ratio, and what is your timming set up at?

 

[stirling33]

Thanks 302Coupe, so would I have been better off sticking with my old cam which was Duration 270/ 280, Lift .448/ .472.....so is there anything to do to overcome this without putting in a different cam?

Oh by the way I have a 4-spd top loader trans.

 

[302 coupe]

I don't think so.

I think your old cam, but with some 1.7 rockers would work very well. Or, you could just stab in a new cam, with 280 ish adv. duration, and and somewhere between .510 and .520 lift. A dual pattern cam like you run now would be good. I run a crane energizer 284H, its an older single pattern design, but pulls great from 2500 up to around 6k, its probably just my heads choking me off even at that rpm. I think a similar cam would be good for you. The 284H still makes good useable power under 2500 rpm, so I'd say its a good street cam, plus it sounds just right. It has a slight lope, but it has that nice choppy/sharp sound that I like. Alot of folks seem to be real happy with the Comp extreme energy series, so you might want to look at those.

 

[rbohm]

actually that cam isnt too large for your motor, well a bit maybe but you should be able to tune around it. what is your initial timing set at? and what is your total timing? did you install the cam straight up?

1: initial timing should be between 10 and 14 degrees with this cam.

2: total timing should be around 36 to 40 degrees.

3: advance the cam 4 degrees.

these changes should pick up that bottom end you lost.